Established in 1983 - 30 years of analog progress!

Kuzma tonearms

1.00000.  Kuzma tonearms - general:

1.00101. What cut-outs are used for mounting Kuzma tonearms?
1.00102. Is it possible to make a Kuzma tonearm pre-cut on a non Kuzma turntable’s armboard ?
1.00103. What cartridge parameters are important for matching cartridges with tonearms?
1.00104. Where is  optimal tonearm resonance?
1.00105. Does damping alter tonearm resonance?
1.00106. Why do 12 inch tonearms appear to perform better then 9 inch ones?
1.00107. Which oil is used for tonearm damping?
1.00108. What are the  effective lengths and mounting distances for various tonearms?
1.00109. What is the capacitance of tonearm cables?
1.00110. Where are the  serial numbers on the tonearms?
1.00111. How much does azimuth angle change with a full 360 degree rotation of the azimuth screw?
1.00201. Where is  overhang?
1.00202. What is optimal tangential geometry?
1.00203. How can I set up the bias precisely?
1.00204. How important is Vertical Tracking Angle (VTA)?
1.00205. How do I set up Azimuth?
1.00206. How do I connect cartridge pins to the cartridge without damaging the wire?
1.00207. How much damping is beneficial?
1.00208. How important is horizontal levelling of the tonearm?
1.00401. How do I rewire Kuzma tonearms?
1.00402. Why do some Kuzma tonearms not have finger lifts?
1.00501. Everything appears to be OK, but one wire is apparently broken to an ohm meter.
1.00502. How do I solder cartridge clips?
1.00503. The bias force is too strong and pulls the tonearm outwards while I am lowering the arm into the groove?

Kuzma tonearms:

1.10000 Stogi & Stogi Ref tonearms:

1.10101. What are the differences between the Stogi arm produced in 1985 and those produced after 1994?
1.10102. What are the main differences between the Stogi and Stogi Ref arms?
1.10103. How does the VTA  kit  for Stogi and Stogi Ref tonearms work?
1.10104. Can I use the VTA system from Stogi Ref 313 VTA on standard Stogi arms?
1.10301. Do the ball  bearings  in any  Stogi  tonearms need lubrication after years of use?
1.10302. How can I  test the bearings on Stogi & Stogi Ref tonearms?
1.10401. How can the tonearm be rewired?
1.10501. There is sometimes difficult to rotate the counterweights from early Stogi models.  What can I do?

1.20000. Stogi S tonearms:

1.20101. Why does Stogi S not have an armrest?
1.20102. Can I mount Stogi S on all turntables?
1.20201. How important is the level of damping oil?
1.20202. Can I use only one counterweight?
1.20401. How can I rewire the tonearm?
1.20501. What can I do if the cartridge is sliding outwards?
1.20502. Why  am I unable to set up tracking force?

1.30000. Air line tonearms:

1.30101. What is the air gap in the bearing?
1.30102. Is there a heavier or a very light counterweight?
1.30103. Why is there a  shiny metal rod?
1.30104. How rigid and strong is the air bearing?
1.30201. How can I level the tonearm horizontally?
1.30202. Does unlocking the VTA lever affects horizontal levelling?
1.30203. How is the counterweight locked?
1.30204. What can be done if the cueing device cannot be moved down easily?
1.30205. What can be done if cartridge is higher at one end of the record than the other when  in “up rest” position?
1.30301. Is the tonearm bearing sensitive to fingerprints or dust?
1.30401. How can I rewire the tonearm?
1.30402. Can damping be added to the Air Line?
1.30501. The tonearm does not travel to the inner groove?
1.30502. How should I ground the tonearm?
1.30503. What can I do if the VTA knob does not work properly?
1.30504. I can hear the compressor switching on and off via audio system?

1.31000. Air supply for tonearm air bearing:

1.31101. Can you describe the principles of an air bearing?
1.31102. Can you describe the basic principle of producing compressed air.
1.31103. Can you describe the air supply system for Kuzma air bearing.
1.31201. How can I set up the Kuzma air supply system?
1.31202. How does the “quick fit” system for connecting air tubes work?
1.31203. How do I  change air pressure for air bearing?
1.31204. How important is it that the working pressure is 4 bar (60psi)
1.31205. How do I seal the red filters ( since 2010 we use silver filters)?
1.31301. What maintenance is required?
1.31302. How can I transport the compressor?
1.31303. When should I change the air filter at the back of the compressor?
1.31304. How do I clean the red filters ( since 2010 we use silver filters?
1.31305. How do I clean the oil and moisture filter below the pressure regulator on the compressor?
1.31401. If I want to use a different compressor, what criteria are necessary?
1.31402. What is the “zero switch kit”?
1.31501. How can I test the air supply system and working cycle of the compressor?
1.31502. I can smell oil in the room?
1.31503. Why do I have no, or inadequate air pressure in the tonearm?
1.31504. How can  I locate where is the problem in air supply system?
1.31505. Compressor failure?
1.315051. What can I do if one of  the automatic seals of  drain tubes is leaking?
1.315052. I have checked everything  but the pressure in reservoir does not reach above 4-5 bars (60-70 psi )?
1.315053. Why is the motor compressor  not working?
1.31506. What if the red filters are leaking ( since 2010 we use silver filters and they do not leak)?
1.31507.  Why can I hear a noise through the audio system when the compressor switches on and/or off?

1.40000. 4Point tonearms:

1.40101. Can I connect both sets of connectors to two different phono inputs?
1.40102. Why do the bearings not feel rigid?
1.40103. What is the counterweight arrangement?
1.40104. Can I take both damping reservoirs off the tonearm?
1.40105. Can I remove the headshell from the 4Point?
1.40106. How many spare headshells are supplied with 4Point?
1.40201. What is the minimum and maximum height of the armboard below the platter for mounting the arm?
1.40202. Is 264 mm distance from the tonearm pivot to the centre of the  record critica(if cartridge can not reach inner groove)?
1.40203. How much damping should I apply?
1.40301. Do the bearings need maintenance?
1.40401. How can I rewire the tonearm?

1.50000. Stogi Ref  313 VTA tonearms:

1.50101. What is the main difference between Stogi Ref 313 VTA and Stogi Ref arm?
1.50102. Can I mount this 12 inch tonearm in the standard position?

KUZMA TONEARMS-GENERAL:

1.00101. What cut-outs are used for mounting Kuzma tonearms?

Stogi cut-out (30mm dia.):
The standard cut-out for Kuzma tonearms is similar to the Linn type and we call it a Stogi cut-out.  Stogi, Stogi S and Stogi Ref all use the Stogi cut-out, which has a main central hole of 30mm in diameter with three holes for screws M6 (48mm dia.) with a mounting distance of 212mm from the spindle to the centre of the tonearm.

Stogi, Stogi S and Stogi Ref tonearms will fit directly onto the Stabi S turntable.  For other turntables you should ask for the Stogi cut-out or the newer Kuzma cut-out.  When mounting Stogi S tonearm onto other turntables you will need an arm base, which must be ordered separately.  This is not necessary with the other arms.

SME CUT on turntables:

You can fit Kuzma tonearms by using KUZMA-SME ADAPTOR if distance is for 9 inch tonearms. See Products>accessories!


The Kuzma cut-out (40mm dia.):
This is for use with our latest tonearms, i.e. Air Line, 4 Point or Stogi Ref 313 VTA.  The mounting distance of 212 mm remains the same but the central hole is larger (40 mm dia) and takes M6 screws.  The screw holes will take both M5 and M6 screws from older Stogi arm bases so that older tonearms can be mounted on the new Kuzma cut-out.  Now this new Kuzma cut-out is the only one provided and will accept all Kuzma tonearms.

1.00102. Is it possible to make a Kuzma tonearm pre-cut on a non Kuzma turntable’s armboard? 

Yes. This should be arranged via our distributors.

1.00103. What cartridge parameters are important for matching cartridges with tonearms?

The tonal character of the cartridge is not significant.  Different combinations of cartridges and tonearms, however, can optimize  tonearm resonance.  This is affected by the tonearm’s   effective mass, cartridge mass and compliance.  Compliance (CU) is a parameter telling us how flexible is the suspension of the cartridge cantilever.  The lower the number,  the stiffer the suspension.  The higher the number,  the more flexible is the suspension.

In practice, low compliance cartridges (CU 5-20) demand higher mass tonearms and vice-versa.

Do not make the mistake of thinking that higher CU cartridges track automatically better than lower CU ones.  For example sports cars have stiff suspension but they track roads better!

Higher CU demand lower mass tonearms and lower mass tonearms, being built with less material tend to be more fragile and flexible.

1.00104. Where is optimal tonearm resonance?

Tonearm resonance means that at certain frequencies a cartridge will have an amplified output which is unwanted.  To avoid music being affected, resonance must be below 20 Hz.  To avoid rumble or signals from warped or eccentric records which are below 4 Hz, resonance should be higher.  It is best to be between 6-16 Hz.  In general, higher mass tonearms will have a lower number (4-14 Hz) while low mass tonearms will resonate at a higher level (10-16 Hz ).

1.00105. Does damping alter tonearm resonance?

Damping mainly affects the amplitude of resonance frequency but not at which frequencies the resonance is.  In practice, the tonearm will shake less but excessive damping can restrict the tonearm’s movement.

1.00106. Why do 12 inch tonearms appear to perform better than 9 inch ones?

A longer tonearm has less tangential distortion.  In theory all pivoted tonearms should sound the same, at least at zero points.  In practice, however, this is not the case.  Tonearms with longer tubes do sound better than shorter ones also at zero points.  One of the reasons is that bias forces are smaller and higher mass tonearms are more stable.  In addition turntable vibration is further away from the cartridge.  The tube itself resonates in a different range.

1.00107. Which oil is used for tonearm damping?

Silicon oil, the main parameter being viscosity.  The thicker the oil (the higher the number) the more damping is achieved.  In addition the deeper the paddle is in the oil, the more effective damping is.

Air Line and 4Point – 5,000 cSt  ( centistokes)
Stogi S – 15,000 cSt

1.00108. What are the effective lengths and mounting distances for the various tonearms?

  Mounting distance Effective length
Stogi S, Stogi, Stogi Ref.  212 mm 230 mm (9 inch)
Air Line 212 mm 180 mm (7 inch)
4Point 212 mm 282 mm (11.1 inch)
Stogi Ref 313 VTA 212 mm 313 mm (12.3 inch)

 

1.00109. What is the capacitance of tonearm cables?

Our tonearm's  cables have these low capacitances (informative data):
Stogi S 58 pF
Stogi S 12 66 pF
Stogi S 12 VTA 75 pF 
Stogi & Ref  58 pF
Stogi Ref 313 53 pF
Stogi Ref 313 VTA 66 pF
4Point   75 pF
4Point  via  box 75 pF
4Point single 42 pF
Air Line 46 pF

 

1.00110. Where are the serial numbers on the tonearms?

To find these on Stogi and Stogi Ref tonearms you need to remove the tonearm.  The number is to be found below the main C part (in earlier arms) or at the bottom of the main support of the black plastic by the cable output.

On Stogi S it is at the bottom of the main tonearm support.

On Stogi Ref 313 VTA, Air Line and 4Point tonearms,  it is on the left hand side of the non movable part of the VTA tower.

1.00111. How much does azimuth angle change with a full 360 degree rotation of the azimuth screw?

With Stogi Ref, Stogi Ref 313 VTA, Air Line and 4Point arms approximately 5.3 degrees.

Moving the Allen key for about the thickness of the key itself (2 mm), with the shorter part inserted in the screw, a change of about 0.03 degrees will occur.

1.00201. Where is overhang?

It is difficult to measure overhang accurately but this is only a starting point for setting up the tangential geometry of a cartridge in a pivoted tonearm.  In all Kuzma tonearms the needle should be at the end of the headshell when looked at from the side.  If the cartridge is properly set up at the zero or null points then all other parameters will be automatically correct i.e. overhang, pivot to stylus and tonearm distances.

1.00202. What is optimal tangential geometry?

We use 66 mm and 120.9 mm null (zero) points on our protractors.  Over the years various theories have been developed concerning optimal tangential geometry.  Initial tracking error measured in degrees was soon replaced by concern for level of distortion, which is different when measured in the outer or inner grooves.  Another aspect which affects optimal geometry is the choice of different starting parameters for measuring distortion in different parts of the record.  Different results are obtained from the same record and this is reflected in the use of different zero points for each theory.  Which is best is not generally agreed.

1.00203. How can I set up the bias precisely?

On a pivoted tonearm, force is created by the needle, which pulls the tonearm tube inwards towards the record centre.  There has to be a compensation angle and the headshell is set at an angle to minimize tracking error .

Antiskating force is created to pull the tonearm outwards in order to negate this effect.  This antiskating force is, more or less, constant, or changes slightly towards the inner grooves, depending on the type of antiskating mechanism on the tonearm.

In Kuzma tonearms the antiskating force increases towards the record centre.  The actual force pulling the tonearm inwards, however, is not constant.  The force on the needle is composed of the force created by the friction of the needle in the groove.  Another force is created by the amplitude and spectral content of the signal in the grooves.  Louder music has larger grooves and thus more force is needed to ride along the complex signals in the grooves.  The signal in the inner grooves is shorter, due to the smaller radii, thus creating higher force.  In addition there are forces, which affect the needle, caused by record warps and eccentricity.  These can even produce negative forces when the tonearm is momentarily pushed outwards instead of inwards.

In practice, therefore, these forces are constantly changing so to fully compensate for them is not possible and precise setting up is pointless.  Of course a test record is sometimes used or the blank space on a record where the tip of the needle is sliding along a flat surface, but this only gives some information as to how the antiskating works.  It is better to rely on the information provided in the tonearm manual.

If using a test record with high tracking modulated grooves you might think that higher tracking is achieved with the highest tracking force and optimal bias to give lowest distortion.  This is not so.  Yes the bias is set very high but being set for maximum signal means that for 95% of the music it is too strong and the tonearm is pulled out too much.

It might be thought that setting up tracking when the signal is at maximum will give undistorted music when most needed.  Again in practice music peaks last for a short time and as the reaction of the bias force is slow the need for compensation has usually passed before it is effective.  If there were a test record with tracking signals lasting a very short time then it could possibly be set up better.  Do you notice that there is no distortion when the needle is lowered into the modulated groove?  So to conclude it is best to set up bias using the tonearm manual for guidance.

1.00204. How important is Vertical Tracking Angle (VTA)?

It may be or may not be.  In a good system even 0.01 mm change can have a significant sonic effect.

Rough guidance is as follows.  Set up the cartridge on the record so that the tonearms tube is parallel to the record or that the central line of the tube is parallel.  Listen to acoustic music and remember the sound.  Then raise the back of the tonearm in 2 mm steps a few times and down a few times, listening to the same music each time.  In principle the higher you raise the arm the more open, analytical and thin the sound will be.  On the other hand lowering the arm can cause a closed, bass heavy and not transparent sound.  Try to find the best sound in this way and make finer adjustments around the chosen starting point.  If you do not notice any major differences this might be because you are a long way from optimal VTA  so move your starting point drastically.  Alternatively it could be because your cartridge, record or system is not so sensitive to VTA  changes.

1.00205. How do I set up Azimuth?

To start you must observe the mirror image of the cartridge on a blank part of a record.  The image should not be tilted to either side.

The best way to adjust azimuth is by using test records or an oscilloscope or by use of a computer program such as Adjust+.

On most of our tonearms we have azimuth with zero play adjustments.  If you use an Allen key as an indicator, you can try different positions in a repeatable way.  Listening to music you should hear if there is more focus, more depth to the instruments and a sense of hall space.  This should be combined with VTA adjustment.  The ease of these adjustments does depend on the specific tonearm.

1.00206.  How do I connect cartridge pins to the cartridge without damaging the wire?

Do not use pliers because you will put too much force on the part of the wire which is soldered under the insulation tube, possibly causing breakage.  It is best to use tweezers which have a lighter gripping force.  Hold the cartridge pin in the area where there is no solder joint.

1.00207.  How much damping is beneficial?

If there is too much damping the low frequencies may be improved but the airiness in the upper mid range and high frequencies may be compromised.  Without damping, lower frequencies may not be well controlled.  In practice this is a matter of experimentation as it is difficult to predict results.

1.00208.  How important is horizontal levelling of the tonearm ?

Some tonearms, due to bearing construction and distribution of mass, are more sensitive than others.  A pivoted arm with separate bearings for vertical and horizontal movements can have mass distributed in such a way that horizontal levelling is extremely important.

Tangential arms, especially those with air bearings, act as spirit levels in themselves so they need very precise levelling.

1.00401.  How do I rewire Kuzma tonearms?

Each arm is different.  In most tonearms the wire is fixed in the tube with damping material and it is not possible to remove the wires without first removing this.  To do this the tube must be opened by removing the headshell and this can only be done in the factory.  Often it is not easy to attach the ground wire or make the correct loop.  Tonearms like Air Line and 4Point, have a plastic tube inside, which allows for easier removal and insertion of wires.  It is best, however, to contact us for details.

1.00402. Why do some Kuzma tonearms not have finger lifts?

We believe these to be unnecessary and that they might compromise performance.  A finger lift is, however, available for all our tonearms and can be attached to the appropriate holes on the headshells.  For Stogi Ref, Air Line and 4 Point this is included in the accessories, while for the Stogi S tonearm it must be purchased separately.

1.00501. Everything appears to be OK but one wire is apparently broken according to an ohm meter?

Check under the pin insulation.  Sometimes the insulation wrap is holding the wire onto the cartridge clip while the actual wire connection is broken at the solder joint.

1.00502.  How do I solder cartridge clips?

The main problem is that hot solder may be sucked into the clip tube due to the capillary effect.  To avoid this, insert a steel needle, small pin or steel nail inside the cartridge pin.  Do not, of course, use copper wire.  Solder will not adhere to steel but will to copper.

1.00503.  The bias force is too strong and pulls the tonearm outwards while I am lowering the arm into the groove.

In some situations the friction between the arm and the cueing device is too low and, therefore, bias pulls the tonearm outwards.

KUZMA TONEARMS

1.10000. Stogi and Stogi Reference tonearms:

1.10101. What are the differences between the Stogi arm produced in 1985 and those produced after 1994?

Although almost identical on the outside there are internal differences, which have caused a dramatic improvement in the later arm.  Since 1994 the arm has had the same ball bearings and wiring as is used in Stogi Reference arms.

1.10102.  What are the main differences between the Stogi and Stogi Ref arms?

The visual difference is obvious as Stogi Ref has a conical tube and Stogi a cylindrical one.  The Stogi Ref tube is machined from three solid pieces of aluminium with tempered inside walls and damping.  This gives a very rigid, non resonant tube.   A sophisticated azimuth system, allows very precise and repeatable adjustments to be made.  This is similar to that in Air Line and 4Point.

Stogi tonearms made prior to 1994 incorporate precise ball bearings but not of the same quality as the bearings used in Stogi Ref arms and in Stogi arms after this date.  These are the most precise bearings which are used in gyroscopes.  They have low vibration noise and low starting friction.  They are assembled in a preloaded configuration.  Stating that a bearing is ABEC 7 or ABEC 9, however, does not ensure that they will automatically be the best in all parameters.  Although bearings are purchased vacuum packed we must still test them before use to ensure that the oil is clean and they are free of particles and have low noise, vibration levels, etc.

The third main difference is that Stogi tonearms before 1994 did not use such good wiring as that in the Stogi reference arms.  Since that time, however, both tonearms are made using the best possible wiring in one piece in a Kuzma custom made cable.  There is no solder joint between the cartridge pin and the RCA or XLR connectors on the tonearm cable and the signal has a clear path.

1.10103. How does the VTA kit for Stogi and Stogi Ref tonearms work?

The VTA kit was designed as an aid for these two tonearms only.  VTA is adjusted by unlocking the tonearm in the base and, while being supported by this kit, it can be raised or lowered in the armbase and then locked back.

The VTA kit consists of a double set of rings which are fitted between the arm base and the main C shape of the arm.  The two rings are held together by a thread and by rotating one ring while the second ring is fixed, we increase the thickness (i.e. height) of the VTA kit.  This controls the height of the tonearm in the arm base.  Due to limited space this allows for only 1.5-2 mm fine height control.  For greater adjustment the VTA ring must be repositioned higher or lower. This VTA  kit will be discontinued in the future. (2009)

1.10104.  Can I use the VTA system from Stogi Ref 313 VTA on standard Stogi arms?

No.  Stogi Ref 313 VTA is a 12 inch tonearm mounted on the existing Stogi Ref position.  VTA is an integral part of the tonearm itself and cannot be used on Stogi, Stogi S or Stogi Ref.  Nine inch (230 mm) arms are just too short to be mounted on such a system.

1.10301. Do the ball bearings in any Stogi tonearms need lubrication after years of use?

No.

1.10302. How can I test the bearings on Stogi and Stogi Ref tonearms?

Holding the headshell pull, push and twist the tube.  Secondly check that friction is within the limits.  The bearings are preloaded, so if you apply a small force you should not feel or hear any slack.  Each bearing itself can withstand 20 kg (40 lbs) force, but preloading is done with 0.5 kg (1 lb).

For the next test you must ensure that you do not damage the cantilever so it is best to protect this or be very careful.  Adjust the bias to minimum by blocking it so that only the twisted wires will force the tonearm outwards and ensure that the turntable is horizontal.

Level the tonearm so that it is floating, i.e. at zero tracking force.  Position the arm above the inner grooves of a record and lower the cueing device.  Release cueing device and the tonearm should float but be prepared to lift up the tonearm in case the needle comes too close to the record surface.  If this happens rebalance it.  The tonearm should slowly start sliding towards the outer edge of the record.  If it moves easily and smoothly then the horizontal bearings are OK.

Remove 0.1 g of tracking force.  The tonearm will slowly move upwards.  Again place the tonearm above the record’s inner grooves and release.  The tonearm should start moving towards the outer edge of the record and slowly upwards.  Next balance the tonearm and add 0.1 g tracking force.  The tonearm will want to move downwards so hold it up with the cueing device.  Position arm over the inner grooves, lower the lift and observe the tonearm moving down and outwards.  It should move slowly and smoothly.  This indicates that the vertical bearings are fine.

WARNING: before the needle touches the platter, mat or record surface, lift up the tonearm!

If any irregularities in movement, such as stops or jerks are observed, repeat the tests and check that the arm’s movement is not restricted by bias, cable or lift etc.   Then consult us.

1.10401.  How can the tonearm be rewired?

This should be done by us in the factory.

Older Stogi Ref arms (prior to 1994-5) have internal tonearm wires and the output cable joined together at the bottom of the tonearm pillar where there is a black plastic cover.  This plastic cover must be removed but, due to the shortness of the internal wire, care must be taken not to break the wires or ground wire.  Other tonearms have wires running from cartridge pins to RCA connectors so the whole cable must be replaced.

This is not so simple.  Wires are inside damping material in the tube and cannot just be pulled out.  First the headshell, which is glued to avoid resonance, must be removed so that damping material can be extracted.  Only in the factory can the glued joint be heated, the headshell removed, the tonearm rewired and assembled back again.  In addition the counterweight’s nickel plated holder must be removed to reach the place where the ground wire is soldered inside the tube.

1.10501. There is sometimes difficult to rotate the counterweights from early Stogi models.  What can I do?

Over a period of time (e.g. a few years of non use- only on early designs) the damping grease on the counterweight may ‘freeze’ making them difficult to rotate when locking screws are released.

It is best to remove the cartridge and the tonearm from the turntable.  One person should hold the tonearm by the tube (to minimise force on the bearings) while the second person tries to rotate the counterweight.  Do not hold the tonearm by the base, but block the base so that the O part of the bearing does not move and damage the tube or main C part.  Due to the damping rings the outer part of the counterweight may rotate while the inner part will not.  It is, therefore, impossible to change the tracking force.  If this is the case, try rotating the counterweight back and forth as this might ease rotation.  If not, spray WD 40 inside the thread away from the tonearm, not on the damping rings and the bearing and wait for half an hour before trying again.  To increase leverage, insert an Allen key in one of the screw holes on the inner ring.

Lastly you can carefully use a heat gun to warm up the inside part of the counterweight and use one or two Allen keys inserted into the holes to increase leverage.

If you manage to remove the counterweight, clean the grease with a cloth or toothbrush and add a few drops of bearing oil.  Rotate the counterweight a few times along the whole length of the thread then clean again and add a few more drops of oil.

If you are unsuccessful then contact us or your dealer.

1.20000.  Stogi S tonearm:

1.20101. Why does Stogi S not have an armrest?

Stogi S was designed as a no compromise tonearm regarding performance with convenience being secondary.  Due to use of damping, however, the tonearm is in itself partially secured and when the tube is accidentally struck this will slow down any jumping of the tube making damage to the cartridge less likely.

1.20102. Can  I mount Stogi S on all turntables?

To fix Stogi S onto turntables other than Stabi S you will need to have an armbase, which is obtainable as a spare part.  Due to its lower centre of gravity, the counterweight needs clearance below the platter level of 30 mm to the armboard.

1.20201. How important is the level of damping oil?

This is not of critical importance but it will affect the cartridge and tonearm system and the stability of the tonearm and consequently the sound.  When assembled the oil level is 10 mm below the reservoir edge.

In principle, top up oil to the indicated level if you are using good low compliance cartridges but feel free to experiment with zero or a small amount of oil and then add more, especially if you are using MM or high compliance cartridges.

1.20202. Can I use only one counterweight?

Yes.  Some cartridges have very low mass and a single counterweight is enough to balance the tonearm.

1.20401. How can I rewire the tonearm?

You cannot.  It should only be done by us.

1.20501. What can I do if the cartridge is sliding outwards?

Clean the lift support to increase friction between the tube and rubber.  Damping slows down movement of the tube thus less pressure (and less friction) on the lift and this causes the bias to pull the tonearm outwards.

1.20502. Why am I unable to set up tracking force?

Tracking force must be set up using a scale.  If the cartridge mass is low (below 5 gr.) then a single counterweight should be used.  If there is still a problem ask for a second smaller counterweight from your dealer.  The same goes for very heavy cartridges.  The normal counterweight configuration is for cartridges between 5 and 15 grams.

Be sure that you did remove wire from tub  to the reservoir.

1.30000. Air Line tonearm:

1.30101. What is the air gap in the bearing?

10 microns.

1.30102. Is there a heavier or a very light counterweight?

Yes. The heavier one looks like a small button and is fixed at the end of the counterweight thread.  It is included with the arm and is intended for cartridges with a mass of over 18 gr.  The lighter counterweight is not completely black.  The rotating part is a light aluminium colour and is available as a spare part and is for cartridges below 5 gr.

1.30103. Why is there a shiny metal rod?

This is optional and it is included with the accessories.  It will provide extra support for the tonearm on some turntables.  It can be fixed in the hole on the end plate near the cueing device.  If it is connected you will be unable to move the VTA downwards.

1.30104. How rigid and strong is the air bearing?

Due to its selfcentering construction, with a high pressure of 4 bars (60 psi), 10 kg (20 lbs) force can be applied before the bearing will show any friction.  This indicates that the bearing is very rigid and stiff with zero friction and no vibration in normal use.

1.30201.  How can I level the tonearm horizontally?

The tonearm itself does not have a levelling facility.  It is, therefore, necessary to ensure that turntable, subchassis and stand support are level.  The tonearm will act as a precise spirit level.

Firstly the turntable should be levelled by means of its support or turntable legs.  Then the cartridge should be fixed on the tonearm and fine levelled as instructed in the instruction manual under ‘Fine levelling adjustment’.  (The manual can be downloaded from the web site.)  The most important levelling is along the bearing shaft axis.

When using the tonearm as a levelling indicator it will take into account all forces acting on the tonearm (horizontal level, wire and air tube loops…).  It is very sensitive.

This is like trying to balance a marble on a glass plate.

Of course the damping paddle must be lifted out of the silicone oil.

1.30202. Does unlocking the VTA lever affects horizontal levelling?

No.

1.30203. How is the counterweight locked?

The counterweight rotates freely along the thread.  If you rotate one part while holding another, the counterweight will become tighter and lock.  Adjust according to preference.

1.30204. What can be done if the cueing device cannot be moved down easily?

The end plate controls how easily the cueing device can be moved down.

Ease of movement depends upon how firmly the end plate presses against the VTA tower.  The firmer this pressure the harder it will be for the cueing lever to move.  (See manual for removal of end plate)  At the same time ensure that the end plate is aligned with the top surface of the VTA tower, otherwise one part of the cueing device will be higher that the other.

1.30205. What can be done if the cartridge is higher at one end of the record than the other when in the ‘up rest’ position?

See 1.30204. and readjust the end plate.  This is done by trial and error.

1.30301. Is the tonearm bearing sensitive to fingerprints or dust?

Not particularly.

1.30401. How can I rewire the tonearm?

This should only be done by us.

1.30402. Can damping be added to the Air Line?

Yes, damping can be simply added but for fine horizontal levelling the paddle must be lifted out of the oil.  See 1.30201.

1.30501. The tonearm does not travel to the inner groove.

Check that the tonearm is in the correct position.  It might be turned too anti-clockwise.  Check with a protractor.  Also check the wires and air supply tube.

1.30502. How should I ground the tonearm?

In most situations it is not necessary to add grounding.  In certain circumstances, grounding a metal part of the turntable can be effective.

1.30503. What can I do if the VTA knob does not work properly?

Presuming that the knob is being rotated not just the lower ring with numbers, as this is an indicator only.

First, check if the VTA height is within the scale of the tonearm.  If it is very high the VTA screw on the shaft might have come out of the thread and will not move tonearm but it will freely rotate.  If this is the case, push down the tonearm and knob so that the screw will catch on the thread.

Secondly, if the tonearm is within the scale.  Possibly an attempt has been made to rotate the knob without releasing the lever.  This could cause the knob to come lose on the shaft, therefore the knob rotates itself only, but not  the shaft.  To increase grip, remove the black rubber ring and expose one or two holes in the grooves.  Using the 1.5 mm Allen key (the same as for cueing device) tighten the screws a little in a clockwise direction.

Similarly if the knob has been rotated with force when the VTA was in the lowest position the same problem can occur.

If the locking lever has been pushed too much, it also might lose its grip and not allow adjustment as VTA  is in the locked position.  Tighten the holding screw gently with the same l.5 Allen key.

If the locking lever does not stop in either direction put it in the lock position and retighten the screw.  Then try to unlock it and you should feel a little resistance showing that the screw is now holding the shaft.

1.30504. I can hear the compressor switching on and off via the audio system?

See 1.31000. Air supply.

1.31000. Air Supply for air bearing:

1.31101. Can you describe the principles of an air bearing?

In its simplest form we have a small plate above a flat surface.  If air is blown under the plate, pressure will lift it and the plate will slide away.  Such a system is unstable. To make the plate float above the surface it is necessary to bring compressed air between both surfaces.  To use compressed air we need to overcome atmospheric pressure.  The extra pressure between two surfaces will create force and push them apart.  In order for this distance to be stable and that the plates do not move away, pressurised air is introduced through holes in the gap on one plate.  The more holes there are, the more stable is the air bearing.  Between the surfaces this air acts as a cushion and a spring but to keep a constant and stable gap the cushion and spring must be as stiff as possible.

Thus the best choice for sliding and rotating motion is a bush bearing.  The bearing shaft is of solid polished metal surrounded by a bearing bush.  A bush bearing has a lot of supply holes or nozzles where air pressure creates force between the shaft and the bush.  Being captured it centres the bush around the shaft.  If we move the shaft towards one side the nozzles have a smaller gap, thus higher force is created and this automatically pushes the shaft towards the centre in order to achieve an equilibrium.  More holes and higher pressure gives a stiffer and more self-centering bearing.  This means that higher force is needed to displace the bearing bush and to maintain the highest possible stiffness of the bearing.  The proper air bearing itself does not act like an air cushion. 

Air bearings have been used for years in equipment when high precision is required, due to the almost zero friction, high stiffness and zero vibration which such a bearing possesses.  The latest bearings do not have a large number of drilled holes but use a porous bearing which has an almost infinite number of tiny holes.

1.31102. Can you describe the basic principle of producing compressed air?

Air around us has a pressure of 1 bar (15 psi).  Compressed air has a pressure above atmospheric pressure.  A compressor (pump) in an aquarium for example, produces pressure that is less then 10 psi above normal air pressure.  The pressure in car tyres is about  2 bar (30 psi).

In principle every compressor or pump sucks air inside a chamber where the air is sealed and then compressed by decreasing the volume in the chamber.  Then this compressed air is moved along a tube and stored in a reservoir.  The problems that arise with the production of compressed air are heat and noise.  In addition air contains a certain amount of moisture and dirt particles.  When air is compressed this is multiplied.  If air is compressed to 8 bar then that means 8 times more dirt and moisture in the same volume of air.  This has to be removed, possibly in more than one stage, before the air can be used, or malfunction and irreparable damage may be caused.

Moisture can be removed in various ways, by water filters, absorber, coolers etc.  The moisture content of air is also variable according the weather and different climates and the more the air is compressed the more moisture has to be removed.

Compressors are noisy and can be divided into two basic types: oil-less – very noisy and oil lubricated – less noisy but with an intermittent working cycle.  With an oil lubricated compressor, some oil will leak into the compressed air where it can block nozzles and make the bearing sticky.  This, therefore, must also be removed by filters.  The hotter the compressor, the more oil there will be in the air supply system.

Compressed air is normally stored in a reservoir which is filled, in pulses, from the compressor.  For smooth operation a steady flow of air is needed.  The reservoir smoothes the flow and a pressure regulator ensures that the pressure and air flow are constant.

The quality of the air thus depends on the amount of moisture, oil mist and dust particles it contains.  For high quality air a great deal of filtering is necessary and filters as well as regulators need regular maintenance, much of which occurs automatically in the compressors.

1.31103. Can you describe the air supply system for the Kuzma air bearing?

The compressor is equipped with an automatic system for all functions i.e.. filling pressure, drainage systems for oil and water and control of output pressure.

The working pressure for the Kuzma Air Line is set at 4 bar (60 psi).  The cartridge will still move the tonearm with a pressure as low as 0.5 bar (1-15 psi) but with a slacker bearing.

WARNING:  The compressor should NEVER work for more than two minutes, which is followed by two minutes cooling down.  This is an automated cycle when the compressor is permanently switched on at the main switch.  If it is left for a long period of time the compressor should be turned off at the main switch below the cover.  See 1.31501 working cycle.

For quieter operation we selected an oil lubricated compressor which consists of a compressor head, powered by an electrical motor, reservoir, air, water and oil filters, pressure indicators and an automatic waste removal system.  It is best located away from the audio system and a tube is supplied that allows location up to 25 m away.  This distance could be increased but it must be situated in a position above freezing point.

Before the compressor’s main switch is turned on, an air supply line for the tonearm must be connected.  The compressor will start to build up pressure from zero to 8 - 8.5 bar (120 psi) in about 3-5 minutes and will then switch off automatically.

The left hand indicator shows the pressure in the reservoir.  When air is consumed and the pressure in the reservoir drops to 6 bar (75 psi) the compressor will automatically switch on and refill the reservoir to 8 bar.  This working cycle is 50:50%.

As air cools down in the reservoir not all the moisture can be contained and some will collect at the bottom.  Every 3 – 4 hours some of the moisture will be emptied into the drainage bottle via the reservoir drain tube.  The timer will open a valve for 1 – 2 seconds and compressed air will push out a mixture of oil and water with a loud short hiss.

At the end of each working cycle some pressure remains inside the compressor head, which is released into the head release tube with a short hiss.

As part of the pressure regulator there is an oil and moisture filter which filters out some of the water and oil from the air.  This is collected in the small reservoir (transparent or black) below the regulator.  Pressure  inside will automatically empty liquid into the drainage bottle via the filter release tube.
These three drainage tubes are not a part of the pressurised air supply for the tonearm but act as exhaust tubes for the automatic drainage systems.  Cleaning is accomplished by occasional bursts of air through them automatically, when air is allowed to rush out for 1 -2 seconds removing moisture and oil.

There should never be a permanent air leak.  If this happens then automatic systems have not sealed properly and the compressor will have difficulty reaching the desired pressure.

Air is supplied by a thin tube to the tonearm.  To ensure that air is free of moisture and oil, extra filters are installed further down the air supply line towards tonearm (silver- in past red filters).  These have an automatic draining system at the bottom which is sealed by pressure.  Only very small amounts of liquid will collect, which will be cleared by natural evaporation.

If the pressure for some reason is too low then the silver filter draining system might leak and pressure will drop further.  This will cause the compressor to work too hard and be unable to create enough pressure.

On the tonearm is a valve which we open to get air into the bearing and the pressure indicator there should also show a pressure of 4 bar.

In case of overheating the compressor will switch off protecting it from further damage.  The motor will, in such a case, not operate and overheating protection will have to be replaced.  See 1.315053.

1.31201. How can I set up the Kuzma air supply system?

Please refer to the instruction manual for further information.

Unpack the compressor and put it in a suitable space which will block the noise but will allow good surrounding air flow for cooling.  Do not close it in a cupboard which has inadequate air flow.  If possible connect the compressor to a mains rig different to that of the audio system.  The compressor can be positioned up to 20 – 25 m away from the tonearm.  If necessary an even longer tube can be attached to run from compressor to tonearm.  If located outside it must be above freezing point.

The compressor is already set up for the correct pressure of 4 bar.

Fix the tonearm onto the turntable and position the red filters nearby in their stands.  They must be in an upright, vertical position.

Remove the cap closing the air intake tube and pour oil into the compressor at the back.  Then close tube with the air filter.

Connect the double drain bottle system to the three thicker tubes on the compressor.  If these are left unconnected it will not affect compressor function but it will make a mess around the compressor as an oil and water mixture spills out.

Connect the longer air tube from the compressor to the silver filter with the valve.  Simply push the tube on until it stops.  These are quick fit connectors  (to release the tube see section 1.31202.).  A shorter tube connects the silver filters and the tonearm.  Keep both air valves (on the tube and on the tonearm) in the closed position as supplied.

Start the compressor by turning on the main switch below the cover.  The compressor will start building up pressure from zero to 8 bar and will switch off in about 3 – 5 minutes automatically.

If this takes longer than 10 minutes then check for leaks and ensure that the air intake tube at the rear of the compressor is not blocked.

Open the valve on the tube and air will rush into the silver filters which will seal automatically seal with the rush or compressed air.  If for some reason they do not seal then pressure loss will be too high and the compressor will work for longer causing overheating.  Should you hear air leaks seal the red filters with your fingers and this will increase pressure, sealing further leaks.  See 1.31205.  Red filters need manual sealing with fingers as descrbed in manual.

Open the valve on the tonearm and the indicator should show around 4 bar pressure.  The compressor should now be working on a 50/50 duty cycle of about 2 minutes (90-130 seconds) on and 2 minutes (90-130 seconds) off.  If the cooling time is a little longer then this is even better.

The automatic timer will occasionally (every 3 – 4 hours) empty liquid from the reservoir into the drainage system causing some noise lasting for about 1 – 2 seconds.  In addition at the end of every working cycle there will be a noise, lasting about 1 – 2 seconds, of air pressure being released from the compressor head.

When not in use close the valve on the tonearm and the compressor will have very low air consumption, switching on only a few times in 24 hours.  If you turn the main switch on the compressor off pressure might drop to zero in a few days via leakage and it will be necessary to re-start the compressor as you did the very first time to build up pressure in the system.  The red filters will lose pressure and will leak until they are sealed again. (See above.)  In normal use, therefore, keep the main switch on and only close the valve on the tonearm when not in use.

1.31202. How does the quick fit system for connecting air tubes work?

Simply push in the right size tube until it will go no further and suddenly stops.  When there is pressure inside it is very difficult to remove the tube from a quick fit connection especially in larger sizes, so it is best to let pressure reduce to zero first.  Then push the blue (or black or metal) plastic ring around the tube, away from the tube pulling the tube out at the same time.  If this is difficult you will need to push the plastic ring away more evenly using two fingers or a metal tool while pulling out the tube.  Ensure that pressure inside is zero.

1.31203. How do I change air pressure for the air bearing?

The compressor is factory preset at 4 – 4.3 bar (around 60 psi).  This is controlled by the pressure regulator which can be adjusted from zero to 5 bar.  It gives a continuous, smooth flow of compressed air.  If the output pressure is lower, then check on the left hand pressure indicator that there is enough air pressure inside the reservoir.  If it is below 6 bar then something is not functioning properly so check elsewhere.  See 1.31505.  If the pressure in the reservoir is below 4 bar the output pressure regulator will not work as it cannot be higher than pressure in the reservoir.

1.31204. How important is it that the working pressure is  4 bar (60psi)?

For tonearm function it is not. It will work fine between 2- 4,5 bar. No damage or any harm can be done even with pressure as low 1 bar  But for best sound keep it as factory set. But if it is between 3.5 - 4.5 bar ( 55-65 psi) it makes almost no difference.

1.31205. How do I seal the red filters ( since 2010 we use silver filters)?

Normally they will be sealed when pressure is built up in the compressor and the valve on the air supply tube to red filters is opened quickly. The red filters must be in a vertical position for automatic seals to works.
Remove them from their stands and shake them or even turn them upside down- but be careful for out coming air or some remain liquid might rush out and cause a mess. This will remove any possible dirt which was preventing sealing.

If pressure is too low they might also not seal. To build up pressure, hold the filters vertically with your hand and with fingers seal the lower black tubes (especially first one) for about 30 seconds then remove them quickly. This will seal the red filters.

Silver filters  seals automaticcaly.

See also 1.31501.

1.31301. What maintenance is required?

Check oil in the compressor monthly when new but every few months afterwards depending on use.  Oil should be visible in the bubble.  If not, switch the compressor off at the main switch then rest it for 3 hours so that all oil collects at the indicator level.  If oil is only just visible then it will need topping up soon but if you cannot see an oil line do not run the compressor until oil is added.  With normal use, however, the oil should last a few years.

Check working time cycles weekly when new, less often later.   See 1.30201.  If the working time is over 5 minutes then turn off the system.  Do not run the system for 10 minutes, hoping that pressure will build up.  If there is a leak or a compressor malfunction the system will not build up a high enough pressure and will overheat causing further damage.

The water and oil mixture level in the drainage bottles should be checked monthly when new and in times and areas of high humidity, less often otherwise.  When the second bottle is half full of liquid you need empty the second bottle only as the first bottle automatically moves liquid into this.  You can, of course, empty both.  Ensure first that the tonearm valve is closed and that the main switch is turned off to avoid the automatic timer switching off and causing a mess.

In the air supply system there are three filter systems.  Normally these are used in industry where there are more severe working conditions.

The Air Intake Filter – at the rear of the compressor where oil is added does not need any maintenance. Once a year remove it and check the intake hole at the side, removing any dust or particles which may have collected.

The Oil, Dust and Moisture Filter – below the air pressure regulator does not need any maintenance with normal use.  Excess liquid will be automatically collected in the drainage bottles.

The Red Filters  or sSlver filters – consist of two bottles containing mechanical and friction filters.  Excess liquid will be automatically drained in small quantities and will evaporate, though in time a few drops of oil may eventually collect.

1.31302. How can I transport the compressor?

The compressor can be moved for a short time if kept in a vertical position due to the oil inside.  When shipping, however, the oil must be removed from the compressor as you cannot be sure that it will be kept in a vertical position.  Remove the cover and compressor head and turn the compressor upside down draining out the oil into a container for an hour.  Replace the cover and either save the oil or obtain new.

1.31303. When should I change the air filter at the back of the compressor?

You do not need to change this, it will last for years under normal circumstances.  Only if air is obtained from a very dusty environment might air intake be slowed.

1.31304. How do I clean the red filters ( since 2010 we use Silver filters)?

You do not clean them.  They were designed for a much higher air flow than our application.  The top indicator will show red when full, but this will never happen.

Silver filters does not have indicators and it will drain automacially.

1.31305. How do I clean the oil and moisture filter below the pressure regulator on the compressor?

You don’t.  It was designed for much higher air flow.

1.31401. If I want to use a different compressor, what criteria are necessary?

Check List:

  • It should not be too noisy.
  • It must have adequate capacity and pressure output.
  • It should have a reservoir for storing and controlling air flow.
  • It should have dust, moisture and oil mist filters.
  • It should have an output pressure regulator.
  • You must obtain from us the final filters silver filters) which are positioned before the tonearm for fine final filtering and removal of moisture and oil mist- or  consult us!

Tonearm requirements for air:

Pressure: 4 bar (60 psi), clean, free of water and oil. (ISO 8573.1 Air Quality Class 3 or 4)

Consumption: 4 litres per minute (gallon per minute)

Compressor data supplied with Air Line tonearm:

SIL AIR 15 Kuzma version, oil lubricated.
Mains: 110V OR 230V/50-60 Hz.
Air output: 12 L/minute (CFM:0.45)
Reservoir: 4 litres (1 gal.)
Power: 150 W.
Noise: 30 dBA.
Mass: 20 Kg.
Dimensions: 220x440x440 mm.

Build in:

Dust filters: 5 and 1 micron.
Moisture and oil mist filters.
Output pressure regulator.
Automatic drainage system from reservoir and pressure regulator.
Overheating  protection.
Automatic safety valve for release of excessive pressure in reservoir.  (If metal ring is pulled air will escape from reservoir).

1.31402. What is the zero switching kit?

If the sound of the compressor switching on and off is audible through the speakers of the system then a ‘zero switching kit’, which eliminates spikes, can be added to the compressor.  (See also 1.31507.)

This is a small box which must be connected inside the compressor’s electrical mains switch.   Connection should only be done by a qualified electrician.

1.31501. How can I test the air supply system and working cycle of the compressor?

Measure the working time of the compressor while the valve on the tonearm is open and ensure that the bearing is working at 4 bar pressure.  Check that the pressure on the left hand indicator is at 6 bar (85 – 95 psi) when the compressor is on and at 8 bar (110 – 125) when the compressor switches off.  The time working, i.e. compressing air, should be in the region of  90 – 120 seconds.  At least the same time should be spent cooling, that is not working, when the pressure will slide from  8 bar to 6 bar at which point the compressor will switch on again.

If the heating time is longer, this indicates that the compressor must work harder, possibly due to leaks or damage inside the compressor, and will overheat and eventually fail.  In this case it should not be used until the problem is solved.  See 1.31504.

1.31502. I can smell oil in the room?

Check pressure on the tonearm and compressor.  Close down the air supply on the tonearm and check the air supply system for possible leaks.  The most likely cause would be the compressor overheating and oil mist travelling along the air supply line.  Start up the compressor and perform working duty test.  See 1.31501.

1.31503. Why do I have no, or inadequate, air pressure in the tonearm?

The air supply consists of three main parts: the compressor, air tubes with red filters ( since 2010 silbver filters) and the tonearm.  We must locate where the problem is and then repair it.  If the cause is a leak then the pressure level will drop due to a large consumption of air and the compressor will be unable to produce enough compressed air.  The result is lower pressure and, due to overwork, the compressor will overheat and even switch off. Overheating  could cause some damage.  See 1.31504 and more FAQ in this section.

First listen for any possible air leaks, checking that all tubes are properly plugged along the air supply line.  If the tubes of the drainage bottle system are not connected they will not affect the air pressure (though there will be a mess around them).  For details see 1.31103.  Check, however, that the red filters are sealed.  See 1.31501.

Close the air valve on the tonearm.  Check the pressure regulators on the compressor.  The one on the left hand side shows the pressure inside the reservoir of the compressor (it should be between 6 – 8 bar) while the one on the right side shows the set up working pressure of 4 -.4.5 bar.  Check the working time of the compressor.  See details in 1.31501.  If these criteria are not met, switch the compressor off and try to solve the problem.  Continued use of the compressor will cause further problems.  Before performing any further tests, allow the compressor to cool down for an hour.

1.31504. How can I locate where is the problem in the air supply system?

Follow the air supply line from the compressor to the tonearm to be sure that the tonearm is not using air.  All valves should be closed on the air supply tube in front of the red filters (not all tonearms have these) and on the tonearm itself.  Listen along the tube for any noise or hiss created by air leaks.

The most likely problem can be with the compressor, or a leak at the red filters.  Check that the air supply tube is not broken, bent sharply or squashed between doors or furniture etc.

Compressor check:

The pressure regulator can be adjusted from zero pressure to maximum.  To separate the compressor from the air supply line, the output should be closed to zero.  The pressure regulator has a knob on the top.  Rotation is only possible when this knob is in the up position – lift it up until a click is heard. To close output, rotate the knob in an anticlockwise direction until you feel resistance.  Unplug the air tube leading to the tonearm.  If any pressure is showing on the left hand indicator, turn off the main switch and release the extra pressure by clockwise rotation of the pressure regulator. When no noise is heard rotate the pressure regulator anti-clockwise again to close the output.

Turn on the main switch on the compressor and observe the pressure indicator on the left side (reservoir pressure).  Air should not leak out where the air supply tube is connected.  If it is then the pressure regulator is not fully closed.

Pressure should automatically start building up and in about 4 – 5 minutes should reach around 8 bar when the compressor will automatically switch off.  Open the pressure just a little.  Air will start to leak out and pressure on the left hand indicator will drop to 6 bar when the compressor should automatically switch on again.  Close the pressure regulator and the compressor should again reach 8 bar and automatically switch off after about 90 – 120 seconds.

If this occurs the compressor is not the cause of the problem.  If these conditions are not met then check further.  See 1.31505.

Red filter check:( since 2010 silver filters)

Connect the air supply tube leading to the tonearm.  Readjust pressure by clockwise rotation of the pressure regulator until the indicator on the right shows 4 – 4.5 bar.  Open the valve on the tube in front of the red filters and ascertain whether the red filters seal or not by listening for any hiss indicating a leak.  Shake the filters and ensure that they are positioned vertically.  If there are any leaks see 1.31205.  If there are no leaks here and the problem cannot be solved see 1.31506.

Listen for possible leaks at the tonearm pressure indicator or at the tonearm bearing.  See 1.31503.

Silver filters seals automacially and  is very unlikley that they will leak.

1.31505. Compressor failure?

WARNING:  If the compressor does not achieve its 50:50 working cycle, do not use it until you solve the problem.  See 1.31501.

The main reason for compressor failure is overheating.  The reason for overheating is that the compressor is working too hard as the process of compressing air generates a lot of heat.  If there is a leak in the system the compressor works harder to supply this increased air demand.  The compressor does have overheating protection which will switch the compressor off.  If this occurs the overheating protection will have to be replaced.  This is located at the back of the compressor where the mains cable is attached.

Damage can occur without overheating when the compressor continues to work, supplying a very small amount of air pressure (about 2 – 4 bar or 40 – 60 psi).  Do not allow the compressor to run for more than 5 – 6 minutes in the hope that the pressure will build up.

See 1.31504 – compressor checking.  If these checks do not give a satisfactory result and the left hand regulator indicator shows very little pressure (less than 1 bar or 10 – 15 psi, or even building to 3 – 4 bar) then close the output by rotating the pressure regulator knob clockwise.  Listen for any leaks or noise, specifically where the tubes join the drain bottles.  More than likely only one of them will be leaking.  Find which tube it is and unplug it (this is not so easy) and check again for noise.  Seal the tube with a finger and listen for other leaks.

If pressure starts building up then the problem is that the seals of one of the drain tubes is not functioning properly and the compressor is losing air, preventing it from building up pressure.  Each tube has its own sealing system.  When the problem is located we must check how to “repair” the drain tubes.  See 1.315051.

Also listen for leaks around the other tubes leading from the compressor head to the reservoir.

If no leaks are heard then there has been damage to the motor head.  There are sealed valves inside the compressor head which, if overheated, break and burn so the compressor can produce little pressure up to only 3 – 4 bar.  See 1.315052.

1.315051. What can I do if one of the automatic seals of drain tubes is leaking?

There are three tubes which drain various parts of the compressor into drainage bottles.  They are sealed with automatic seals. If they are not sealing properly this will cause a leak, an increased demand for air supply, problems of reaching desired pressure and eventual overheating of the compressor.

The three tubes are, from top to bottom:

Head release tube – the top tube is connected below the main switch and releases pressure (with some oil mist) from the compressor head, at the end of each working cycle, into the drain bottle.  (Every 4 minutes a loud noise can be heard created by this air pressure release, the noise lasting about 1 – 2 seconds.)  It is sealed by an automatic piston valve.

Filter release tube – the middle tube is connected below the pressure regulator and releases a mixture of water and oil, which is collected in a bowl at the bottom.  It is connected via a metal L shaped connector and quietly releases liquid occasionally into drainage bottles.

Reservoir drain tube – is the lowest tube and releases liquid (a mixture of water and brown oil) which has collected at the bottom of the reservoir.  It is connected to the reservoir via an automatic electrical drainage system and is controlled by an electrical timer on the lower front part of the reservoir.  This timer is switched on every 3 – 4 hours.  (It could be set at any time from 1 – 12 hours).  An electric solenoid moves the piston, opens the valve and releases pressure from the reservoir in 1 – 2 second long bursts, removing some of the liquid from the reservoir into the drainage bottle, before sealing it back.

If any small particles are caught in these automatic drainage systems the seals will not close properly and air will leak out causing high air consumption or preventing pressure build up.  This problem will cause failure of the working cycle test.

First try to remove particles from the seal by letting through more pressurised air in an attempt to clean surfaces or paths ( press TEST button-see below).  Of course if there is no air pressure in the compressor this will not work so try to seal tubes with fingers to increase pressure.

Sometimes tubes become clogged even if there is no leak.  If dirt is not removed it can be pushed back clogging another drain tube or automatic system and in addition, with a clogged tube, it will not be possible to detect any leaks.  To check that tubes are not clogged all tubes should be disconnected from the drainage bottles.  Do not forget to reconnect them.

Perform these tests and check that pressure on the left hand indicator is starting to build up.

Compressor’s head release tube:

Dismantle the piston system below the main switch and clean it with alcohol.  Replace this and try it.  Although unlikely, damage to this seal system is invisible and we will supply you with a spare part.

Filter release tube:

A leak is occasionally caused by small particles blocking sealing valves.  There is an L shaped metal part where the tube is connected.  Push it up and the pressure inside will push liquid out into the drainage bottle.  Then try to shake and move the metal part until it seals back.

Reservoir drainage tube:

This valve is opened electrically.  It is sealed by a piston and spring constantly, even without electricity.  When switched on an electric solenoid with a timer will pull the piston and release both pressure and liquid.  This can be done by pressing the label marked ‘TEST’.  If there is a leak and pressure in the reservoir is above l bar or more, press this ‘TEST’ button.  You will hear a click and the release of pressurised air will hopefully clean the seal.  Wait for the compressor to build up pressure and press ‘TEST’ again repeating the process a few times.  If you still hear a leak then the valve must be cleaned.

Valve cleaning:

To clean the valve which is the most likely cause of a leak first unplug the compressor from the mains then let air pressure go to zero in the reservoir.  Note the following assembly.

Unscrew the connector on top of the timer.  Lift up the timer and release the nut with ‘U’ key 14 mm.  Remove black block and the rounded metal tube-valve will be exposed.  With ‘U’ key 13 mm. you can unscrew this, being careful not to lose the piston and spring inside.  Clean the brass block inside with alcohol, then clean inside the piston and spring and re-assemble.

Plug in compressor, turn on main switch, ensure that drainage bottles are connected (or use a PVC bag to collect debris) and when the reservoir pressure indicator shows at least 1 – 2 bars, press ‘test’ and listen for a leak.  If you hear nothing, wait until maximum pressure is reached and repeat this ‘test’.

If there is still a leak and you hear no clicks of the valve solenoid (one at the beginning and one at the end of 1 – 2 seconds), the problem could be electrical, a faulty timer or the solenoid is not moving the piston.

Normally if you press ‘TEST’ LED shows even if there is no click or air leak noise.  If no LED shows for 1 – 2 seconds then the timer is faulty.  Check that there is mains electricity and that the motor is working.

If you do not hear a click, the solenoid is not moving the piston.  Both these parts are available as spare parts.

1.315052. I have checked everything but the pressure in the reservoir does not reach above 4 – 5 bar (60 – 70 psi).

Do not run the compressor for more than the working cycle or for a maximum of 5 minutes when trying to solve the problem.  If there are no leaks and the compressor is running all the time, failure of the compressor head is most likely.  If the seals inside the compressor have failed they must be replaced.

Unplug the compressor.  Remove the compressor cover and compressor head.  At the back you will see inside 4 screws holding a thick square metal plate which is not easily accessible.  Beyond this are 2 thin metal seals with two sealing plates.  Try to remember the order of assembly.  You will need to obtain a compressor seals kit.   For this contact a specialist in air compressor repairs.

1.315053. Why is the motor compressor not working?

This could be caused if the overheating protection has switched off the motor.  In this case it needs replacing and the problem of overheating must be solved.  It is located at the back where the cable enters the compressor and it must be replaced by a qualified electrician.  (We will supply the part).

Although unlikely the compressor head might be blocked because  lack of oil prevents motor rotation.  Do not try to run it.  Unplug the compressor and arrange for a specialist service of the compressor.

1.31506. What if the red filters are leaking ( since 2010 we use silver filters and they do not leak)?

First perform the sealing process.  The compressor must give an output of 4 bar.  See 1.31205.  When the pressure drops below 0.5 – 1 bar, seals will not function!

The red filters must stand vertically.  If you cannot seal them by shaking them in their stands, lift them out and see if, by slightly tilting them from the vertical, you hear the leak stop for a short period of time.

To clean seals, turn the filters upside down.  Air pressure will rush out.  If necessary clean out any debris along with any moisture that will have collected.  Shake them a few times, turn them upside down a few times and then try to seal them.   This is normally effective.

If you hear a hissing leak at the top where there are the black plastic tops and indicators, there are two possible causes.  First there may be damage to the top part, or a sealing ring inside may be broken.  When pressure is at zero, use a screwdriver and check rings below. Check that the two small ‘O’ rings are present around the black plastic nozzle.  If not, or damaged, replace. These parts are available from us.

 

Silver filtertare more reliable then red filters!

1.31507. Why can I hear a noise through the audio system when the compressor switches on and/or off?

The on/off noise comes via the mains line into the audio system.  Sometimes RFI (spike filters) mains line filters in front of the compressor might help.  If possible, connect the compressor to a different mains rig.

If you cannot do this we can supply a ‘zero switching kit’ which eliminates spikes.  This is a small box which must be connected inside the compressor’s electrical mains switch.  Connection requires a qualified electrician.

1.40000. 4Point tonearm:

1.40101. Can I connect both sets of connectors to two different phono inputs?

Yes, especially if you use two different phono stages.  If your phono stage has two inputs, you might need to halve your chosen input impedance.  Always connect only one ground wire.

The tonearm has two independent sets of wires; bi-wiring and this allows you to try different cables and compare them to the tonearm’s own cable.

1.40102. Why do the bearings not feel rigid?

The design and construction of the bearings are such that there is zero play only in those directions which are mandatory.  Try to pull the tonearm along the tube and then try to twist the headshell – with reasonable force – and there will be no slack.

1.40103. What is the counterweight arrangement?

There is a set of counterweights for balancing tonearm cartridges from 2 – 30 grams.

In this way the counterweight are nearer to the vertical bearing. You can use any configuration, moving them up or down the thread and locking them into position by screwing them together.

1.40104. Can I take both damping reservoirs off the tonearm?

Yes.  This makes it very easy to remove oil.

1.40105. Can I remove the headshell from the 4Point?

Yes.  4Point has a detachable headshell which is designed without any compromise of rigidity, precision or electrical connection.  It is simply removed.

1.40106. How many spare headshells are supplied with 4Point?

One extra is supplied but more can be obtained.

1.40201. What is the minimum and maximum height of the armboard below the platter for mounting the arm?

Clearance below platter to armboard can be 36 – 78 mm.  If more or less is required please consult us. See mounting template and protractors- technical manual.

1.40202. Is 264 mm distance from the tonearm pivot to the centre of the record critical?

Yes.  The bearing configuration of the tonearm has a limited arc of movement.  If the distance is larger or smaller, then check that the tonearm can still reach the last locking inner groove and that the needle passes the edge of the record easily.  A rigid plastic protractor is supplied with the tonearm so you can achieve this distance without measuring. If you can not reach inner grooves check 264 mm distance and make it shorter to 263 mm!

1.40203. How much damping should I apply?

Feel free to experiment but be careful that the paddle is not too deep in the reservoirs as it might scrape the bottom and restrict movement.  Start with horizontal damping first.

1.40301. Do the bearings need maintenance?

Not in normal circumstances.

1.40401. How can I rewire the tonearm?

This should only be done by us.

1.50000.  Stogi Ref 313 VTA tonearm:

1.50101. What is the main difference between Stogi Ref 313 VTA and Stogi Ref arm?

There are three main differences.  First it has an effective length of 313 mm, which is over 12 inches.  Despite this length this 12 inch tonearm requires the standard mounting distance of 212 mm as with any 9 inch tonarm.

Secondly, it has a VTA tower which is precise, rigid, easy to use and enables repeatable changes in VTA in a range of 0.01 mm.

Thirdly, it has a detachable headshell, which is designed without any compromise of rigidity and precision and does not compromise electrical connection.

1.50102. Can I mount this 12 inch tonearm in the standard position?

This is the only way.  It will not fit a 12 inch position.  Stogi Ref 313 tonearm is mounted on a standard 12 inch distance, but it has no VTA tower.

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