My Linn Axis is Sick. Please help fix

Status
Not open for further replies.
Jump to Latest
#41
I'll give that a try,
just been reading some comments on vinyl asylum referring to the suspension (joke) on the axis transferring sub audio frequencies at around 5hz from the motor to the subchassis/arm. Sounds feasible but you would think that everyone with a system which includes an axis and a sub would experience this unless they have low fequency filtering on phono stage.
 
#42
Hex48 said:
I'll give that a try,
just been reading some comments on vinyl asylum referring to the suspension (joke) on the axis transferring sub audio frequencies at around 5hz from the motor to the subchassis/arm. Sounds feasible but you would think that everyone with a system which includes an axis and a sub would experience this unless they have low fequency filtering on phono stage.
Click to expand...

Is this just a case of too much feedback from you sub, and not having a rumble filter either on the sub itself (plate amp), or between the phono and main pre?

Jeff
 
#43
possibly all of the above, PM, tried your suggestion of manual op of table with belt off and motor stopped, got the same VLF noise.

With the platter stationary the noise stops but the slightest touch on the plinth and it starts up again and gradually dies away. The whole thing is very microphonic and the sub is quite close, VK58, my Creek phono stage goes down to DC, the Cyrus pre-power also go down to dc and the MJ Acoustics sub seems to give an output as low as 1hz (judging from the driver excursion) so there is no rumble filtering & it could be an audio feedback loop.

Think I'll put a scope on the decks outputs and see whats coming out & try switching off sub/moving deck etc.

Pete
 
#44
Does it happen at any other time than with the unmodulated rumble track. 5-10Hz is pretty low, I wouldn't expect to see that from a motor. That could be a bearing problem. That frequency is what you see with a record warp. What arm and cartridge are you using? Could the arm/cartridge combo resonate at the same frequency as a record warp? Try another record, a very flat one through an unmodulated area(silence).
 
#45
Hi, TKwou
The problem occurs with all records to a greater or lesser extent, I used the unmod track on the test record to try and pin it down because the disc is pretty flat and there shouldn't be any other signal to drive the sub. I first realised there was a problem playing organ music and the sub got red hot although the volume was not excessive, the same piece from CD did not cause any problem.

PeteMoreton suggested running the platter without the belt, I did and LF noise was still there so it cannot be the motor, and to be honest I don't think it's the main bearing because with the stylus on the record and the platter stationary I can start this VLF"rumble" just by lightly touching the plinth. It feels as if there is some natural resonance which is kicked off by almost anything. I read on another forum that the suspension was designed to have a resonance below audio frequencies, wonder if thats the prob?.
The arm is an Akito 1, the cart an Audio Technica AT440ML.

Pete
 
#49
Hi everybody!

The Axis schematics kindly provided by two fellow members, only do have the components order #s for the PCB, not any values or codes.
Does anybody have other shematics showing these values/codes?

The most urgent cases for me, are R2 and R3 which are simply missing in the motor board I've got, and also R1 and D1 may not be the original ones, so if anyone could confirm all this, I would appreciate much.

Thanks, cheers, JPB
 
#52
Hex48 said:
Hi, TKwou
The problem occurs with all records to a greater or lesser extent, I used the unmod track on the test record to try and pin it down because the disc is pretty flat and there shouldn't be any other signal to drive the sub. I first realised there was a problem playing organ music and the sub got red hot although the volume was not excessive, the same piece from CD did not cause any problem.

PeteMoreton suggested running the platter without the belt, I did and LF noise was still there so it cannot be the motor, and to be honest I don't think it's the main bearing because with the stylus on the record and the platter stationary I can start this VLF"rumble" just by lightly touching the plinth. It feels as if there is some natural resonance which is kicked off by almost anything. I read on another forum that the suspension was designed to have a resonance below audio frequencies, wonder if thats the prob?.
The arm is an Akito 1, the cart an Audio Technica AT440ML.

Pete
Click to expand...

OK, I've just read through this post (sorry if this is too late) and here is my view based on my experimentation with turntables and subs. You are experiencing low frequency feedback - it's as simple as that. The suspension on the axis is particularly inefficient in the vertical plane and really only creates instability in the lateral plane. Vertical movement is resisted and converted into lateral movement which is picked up by the stylus and so on. The axis suspension elements have a tendency to sag over time - they were a nice idea but the execution is really not that successful. As I remember, the suspension diaphragm of each element of the suspension is visible from below the deck - try filling this space - does altering the suspension alter the effect on the sub?
 
#53
YNWOAN said:


OK, I've just read through this post (sorry if this is too late) and here is my view based on my experimentation with turntables and subs. You are experiencing low frequency feedback - it's as simple as that. The suspension on the axis is particularly inefficient in the vertical plane and really only creates instability in the lateral plane. Vertical movement is resisted and converted into lateral movement which is picked up by the stylus and so on. The axis suspension elements have a tendency to sag over time - they were a nice idea but the execution is really not that successful. As I remember, the suspension diaphragm of each element of the suspension is visible from below the deck - try filling this space - does altering the suspension alter the effect on the sub?
Click to expand...

Sure, the Axis MDF top plate with the platter/subplatter/bearing assembly plus the tonear, means a lot of weight, which causes the pseudo-suspension to sag, specially one of the diaphragms which is much thinner than the other two. Under tension these diaphragms loose their damping ability, being prone to ressonate to some audible frequencies. Just like when we tight an instrument's string, or drum skin. The more we thighten, the higher will be the ressonance frequency...

Cheers, JPB
 
Status
Not open for further replies.
Top Bottom