Linn LP12 motor malaise ?

[lohk]

Does someone of you analogue-folks have any ideas or experiences and suggestions about getting rid of the non-ideal airpax synchronous motor ?

I would like to convert my Linn LP12 to CD operation, and my Systemdek900x too.

The airpax motor is getting noisier by time and it is a crude item anyway.
Pink Triangle (do they still exist?) made a very strange conversion kit 10 years ago. I think, and Origin Live probably still does. Hard to get this stuff here anyway.

Klaus

 

[dice45]

Klaus,

yes, i have. In another thread i suggested a moxon motor and i do not see any reason why this maxon shoul no be mounted into a Linn or Systemdek. Just consider the motor's *** (containing the noisy commutator) should be encapsulated airtightly.

You remind me i should get my hands on what is left of those maxons i tested recently.

 

[mrfeedback]

......... Just consider the motor's *** .........

LOL .....

 

[lohk]

mrfeedback:
Do not laugh about simple typos and us non-native speakers !
(- and to think "***" is funny: how old are you, man ?)

Bernhard,

thank you. Can you tell me which thread ?

I, btw, have two maxon motors already, which run with low DC voltages with very little noise and almost no vibration (a smaller one and a bigger one salvaged from a VCR). I do not know what you mean by making them airtight ?

Klaus

 

[jam]

Klaus,

How is the speed stability with the Maxon motors?

Jam

 

[mrfeedback]

mrfeedback:
Do not laugh about simple typos and us non-native speakers !
(- and to think "***" is funny: how old are you, man ?).....Klaus.

Hiya Klaus, I don't mean to discriminate between native english and non-native english speakers typos - indeed, both can be equally funny.
*** ? - A repeat Beavis and Butthead movie was on TV late last night, and I belly laughed out aloud, and I'm 40 something.

Smiles and regards, Eric.

 

[dice45]

maxon: ideal choice for TT motors

Jam,







Speed stability of maxons is fair-to-good (together with the commutator noise their only drawback); i do not know whether it is the motor or the lab supply which is drifting.







But it is a very slow drift and in no way affecting the music.



However, it has to be checked regularly. Unless you buy a Teres motor /controller kit which uses a maxon and has a µcontroller checking the slow speed drift and correcting the motor supply voltage.







Klaus,







nice of you to defend me, but i do not sense a language barreer with native speakers here and sometimes i am a bit blunt in my choice of terms; "***" was meant to be a sharp-minded pun. ***** produce some ... hmmh .. not-continuous noise signal shapes. Unpleasant noises (except to the own ears ) ... but whereas human ***** do so now and then, the maxon's *** does it all the time when running. And while my *** cannot really be kept airtight ( must have to do with exchange of not-neglectable amounts of gasses, would discomfort me considerably ), the maxon's *** can be sealed up and ---whoosh--- the unpleasant noise is gone.







I looked for the thread meanwhile, it is the "TT motor slightly bent".







All (particularly lurkers),







the maxon commutator noise is rather silent, but is is noticable within a distance of , say, 1 meter. But as many lesser TT motors (synchonous motors, split-pole asynchronoous motors, electronically commutated motors) are usually dead silent, the motors from maxon and their direct competitors Faulhaber are criticized frequently for their commutator noise which is rather silent but not dead-silent.







But these maxon motors with bell-type iron-less rotors having up to 11 overlapping windings excel for TT application. They are unbeatable as far torque ripple, low rotor inertia, high dynamic stability is concerned and they are precision-made for precision applications: the shaft has excentricity/wobble close to zero (less than 5µm). And they do not ask much for that: a clean DC voltage. Angular speed and supply voltage are linearly related, can be it be easier? 16rpm is no problem, 78 rpm neither.







Exactly what we need for a TT motor, provided we can tackle or tolerate minor flaws.



Ooops. forgot, retail they cost between 60 and 200 US$ each, depending on quantity and supplier.

 

[lohk]

Bernhard,

I must admit that I did not get the point off the "***" pun until your explanation - I thought you mean "assembly" for what ever reason. ( -> I wish my english would be as good as yours...)
But you are adressing the main problem what I have with this motors: The noise.
Noise is the right word for it, it is a soft but very irritating high pitched "whirring" sound. I normally hear even the otherwise silent synchronous motors of my turntables in 2 -3 m distance.
One of the maxon moters is already closed at the backside, but still emits this sound.

My two Maxons:
1. 2141.923 - 50.011 - 003
This is a 4 x 4 cm quite heavy motor with a machined pulley, probably from a VCR. The backcap is fallen off and shows a PCB with a SMD RF filter.
I found this item - please laugh! - at a junkjard in vienna, where it got bags full of electronic parts (philips, roederstein, frako, nichicon, wima, etc.) in mint condition for ridiculos money.

2. 2023.913 - 20.101 - 044
This is a 3 x 2(dm) cm motor made from hard solid plastic and with an integrated fixing assembly and a brass pulley. It is closed from the backside with another red plastic (but still sounding ...).
I bought this one at Neuhold Electronic in Graz/Austria as new (without specs) for 1.5 EURO ! ( - they seem to have lots of them. The friends from the model railway business seem to like them). It runs otherwise like a dream with a few volts.

I have no specs for both motors. They run beside the sound problem very good and seem to have lots of power with just a few volts and slow speeds. But you mean other motors perhaps.

Do you, Bernhard, think it is sufficient to wrap them in some damping material to get them quite?

Klaus

 

[dice45]

Klaus,

thank you for the compliment, but my typing ! awful!

My suggestion for all those maxons having a smooth, unintererupted outer surface:
Clamp the motor within a pair of rubber O-rings (the rubber usually being Perbunan or some other acryle-citrile rubber) at its outer cylindrical diameter instead at the flange.

Make a bushing fitting to the motor's and o-ring's dimensions so that the motor is clamped airtight. Of course the bushing shall be closed at its other end and only a small hole for the wires shall left open which can be sealed with silicone glue after the motor was mounted.

TME this gives very satisfying results. Additional benefit: the motor and its pulley can be height-adjusted (within limits )to suit your needs. So no particular precision is needed for height position. DIY-friendly.

 

[Vinylsavor]

Maxxon Motor

All,

I'm using a Maxxon motor since quite a while with my Scheu.
When the motor which came with the Scheu died, I replaced
it with a Maxxon. I kept the housing of the Scheumotor,
which is basically a stainless steel tube mounted on a base
which holds the on/off and speed switches.

I used Sorbothane feet to damp the noise from the motor.
I had some of the audioquest Sorbothane feet lying around.
I cut out a whole in the center and stripped them over
the motor. The whole thing I pushed into the steel tube.
Sits tightly and is quiet.

As for speed stability: I use a simple LM317 regulator
chip which is mounted in the motor housing. Occasionally
I check the speed, but I rarely need to adjust it.

Thomas

 

[hifidaddy]

Maxon motor

I am using the same Maxon as vinylsavor for my 100mm high Scheu platter, and it works good, stability is very good, I didn't need to readjust the speed so far. Though my motor housing isn't optimal, it rather exaggerates the motor noise, so at my place, I can hear some of the motor noise. Indeed, you have to put the Maxon motor in a damped hole to prevent it from farting.

Here in Munich, we have tried some cheaper Maxon motors, too, which we bought in surplus shops, but we found them noisier and less stable from speed than those models "officially" recommended in the Verdier tuning articles from Goetz Wilimzig in the Swiss "Hifi-Scene" and also in Sound Practise Magazine. I paid around 60 USD for my Maxon motor, which is the successor of said recommended model.

BTW, the LP12 AC motor should be silent. Otherwise it must be defective. I had an LP12 for many years without any problems.

regards,
Hartmut from Munich

 

[lohk]

Hartmuth, Thomas & Bernhard,

thanks for your replies.
There seem to be a strong German fraction in the TT league in this forum. Do you guys post in german speaking forums too ?
I personally only know the audiomap forum, and it often seem to be a kind of "kindergarden" to me - I prefer knowledge, humour and manners here period.

Back to the subject:
The bigger one of my Maxon motors seem to be very suitable for a TT motor.
So I need some good advice: I have a platter and a subplatter plus bearings from a Heybrook TT2 and various tonearms (in different shape).
It is probably better to start to build a DIY TT !?
But that would be another thread perhaps.

Noisy Linn LP12 motor: There is a modification which Linn applied. A small steel ball together with a spring in a sealed encasing is pressing the axle against the bearings. This mod - probably intended originally for better running or less noise - is getting out of alignement and is then producing a soft but annoying noise.
I just do not know how to repair it. I did correct it several times in the eighties (when I was working part-time in retail and repair) but I do not remember it correctly.

Klaus

ps: Does Scheu have some parts for the LP12 ?

 

[dice45]

Klaus,

forums:
I left them all, lurk there now and then, post almost never. Because of the manners there. Sometimes i get temped to re-join the Joe-Net, particularly when the Aarhus Triode Audition Festival is approaching.

Heybrooks parts:
too ringy for my taste. If you want to use them, please de-ring them but take care to spread the added mass equally; the center of gravity/inertia shall remain on the spindle's centerline.

Linn:
same, see above. Heretic me
I did not know Linn was adding a spring piece somewhere in the bearing, must been after i was Munich's Linn repair/setup man. But i second your unease: any grinding noise coming from the platter bearing is of utter evil. If the motor bearing is concerned, sonics are only slighly affected, but the motor's life time is heavily affected.

Scheu:
ask Hartmut but i presume Scheu has only his own parts. If i would be him, i would not consider to have Linn parts.
Modifying Linn: Still a good way to spoil the own rep and having every other Linn fanatic yapping about "this heretic".

 

[lohk]

Bernhard,

the Linn LP12 was clearly the best TT I could get my hands on when I bought it - it still works fine after all those years.
(I must admit that I was in business within a Linn/Naim/British stuff selling company for some years... setting up and all that; good experience though)

I did not put the argument correct: The Linn bearing does not have a counterspring of course (??) and the noise does not come out of the platters bearings. That really would be evil.
No, it is the motor and the sound is not from a vibrating pulley or the like. No problems with the sound so far, but still...

But modifying a Linn ? Why not ? I do not care to lose my reputation, what the heck.
I know, that this item, although good, was by far from beeing perfect. It simply was a brilliant compromise.

The TT2 platter is actually less ringy than the linn platter. But I am not sure about the bearing.

Hartmut,
where do I find the Verdier tuning articles from Goetz Wilimzig in the net ?
I heard the Platine Verdier several times, but only for short. Clearly better than my LP12 but for what cost ?

So you guys emphasize on DC operation anyway ? I was not aware of that, but I must admit that the Digital age is already making me pay less attention to analog affairs.

Klaus

ps: Can you knowledgeable DIY analogue people post some links here for us less experienced?

 

[Vinylsavor]

Klaus,

I don't participate in other TT related forums. My main interest
is tubes. I've built amplifiers, linestages and one of my specialities
are phono preamps. Oh, yes, there is also a DAC, which I
called the 'CDsavor'. I occasionally participate in german
tube forums.

For TT matters, I rely on the expert advice from Hartmut and
Bernhard.

We're quite lucky here in Munich, having a loose group of
severel audio nuts. Each experienced in different fields
and with different tastes. Occasionally we're called the
Munich Triode Mafia.

Ciao

Thomas

 

[hifidaddy]

Klaus,

I am member of http://de.groups.yahoo.com/group/vinyl_lebt/
which is the leading German language vinyl discussion forum, you can have it online or email as you like it.

Scheu doesn't do parts for Linn, only an acrylic platter for Rega.

I have an AC motor, too, it is a Pabst outer rotor 24 volts from a Transrotor turntable in chrome housing, looking quite good and running really silently. With my heavy acrylic platter (10kg), there is little difference between the motors, sonically.

regards,
Hartmut

 

[J Epstein]

lohk:

It has been my pleasure to meet many of these Munich Triode Mafiosi, and perhaps a word of advice is in order:

If you go to Munich, bring your beer bottle opener and your cigar cutter! And be prepared to breathe a lot of superheated air!

Seriously, I wish my finances were in better shape, I would love to see my Munich friends, they are wonderful guys. And it is truly impressive what happens when you get such a large number of audio-crazies in such a small area, they spur each other on to higher and higher insanity!

 

[mrfeedback]

motor suggestion

Hello All, after following this thread, I thought of VCR brushless direct drive capstan motors.
You may have to fit a suitable pulley.
These have a frequency generator output so a suitable phase locking speed control could be used (or modified).
Elsewise just give a stable dc speed control voltage.
These run silently, have good speed stability, and are easily available for free from wrecked vcrs.

Maybe this can help you TT types.

Regards, Eric.

 

[dice45]

Jeremy,

who needs a beer bottle opener to open a bottle of beer? only wearers of mickey mouse socks and warm-douchers and women-understanders and the like

Nearly anything can open a bottle of beer with more style , e.g. I use the handle of my surgeons scalpel and its oither end will do a fine job to cut Thomas' cigars

 

[mozfet]

Maxxon

Which model numbers are suitable for TT use?

Mozfet