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Old 2nd April 2002, 10:30 PM   #1
lohk is offline lohk  Europe
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Default Linn LP12 motor malaise ?

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
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Old 3rd April 2002, 10:52 AM   #2
dice45 is offline dice45  Germany
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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.
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Bernhard
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Old 3rd April 2002, 12:21 PM   #3
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Quote:
Originally posted by dice45
......... Just consider the motor's *** .........
LOL .....
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Old 3rd April 2002, 04:30 PM   #4
lohk is offline lohk  Europe
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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
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Old 3rd April 2002, 04:36 PM   #5
jam is offline jam  United States
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Klaus,

How is the speed stability with the Maxon motors?

Jam
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Old 3rd April 2002, 05:03 PM   #6
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Quote:
Originally posted by lohk
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.
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Old 3rd April 2002, 05:25 PM   #7
dice45 is offline dice45  Germany
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Default 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.
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Bernhard
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Old 3rd April 2002, 09:41 PM   #8
lohk is offline lohk  Europe
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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
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Old 3rd April 2002, 11:38 PM   #9
dice45 is offline dice45  Germany
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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.
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Bernhard
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Old 4th April 2002, 08:42 AM   #10
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Default 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
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