TT DC motor, Disperate lease help me

[kephaudio]

Hi dears,

I was planning to built a TT with an heavy platter. I have a very good bearing, and I know hot to procede unless that I have to decide for the motor.

I would go for DC motors, I was suggetsed Maxon motors, (which one? and where to buy in Europe?). But I was also told that Maxons are not that exceptional. I heard that there are other motors cheapper and good as the Maxon is. Ok but which one to buy? Where?

I hope someone will help me, many thanks in advance
KEPha

[Aquarium]

Try this site

http://www.premotec.com/

[Soundadvice]

As Aquarium rightly says permotec , look for the coreless dc motor for smooth operation !

as for speed control look speed control ic`s from sgs ! the sort used for printers etc. (just put tthis into a search engine)

sorry I dont have the link, I tried to attatch the pdf doccument but this site said the file was to big !

[kephaudio]

Originally posted by Soundadvice
As Aquarium rightly says permotec , look for the coreless dc motor for smooth operation !

So I checked but there is something not clear in the data sheet.
Suppose I look at the CL29-3, so for example the 6V motor of this series should produce a 'nominal speed' of 2680 RPM.

The are two things obscure to me: what 'nominal speed means'?
Second: the speed can be varied from 0 Rpm up tp 2680 RPM varying the applied voltage? Or I need to apply a fixed voltage?


as for speed control look speed control ic`s from sgs ! the sort ?used for printers etc. (just put tthis into a search engine)

I am sorry I am not into this kind of things, I always worked with AC motors, could you exlpain a bit more clear.

sorry I dont have the link, I tried to attatch the pdf doccument but this site said the file was to big !


you could sent it to kephaudio@yahoo.it, I would appreciate very much that, please help me!

KEPha

[ARAD]

Hi Kepha,

I just finished building me a new motor assembly for my BIX turntable and used a Maxon motor (the exact type is 2140.937-22.112-050). The motor is a 24 V DC type and was recommended for this application by a Maxon representative of the Munich Maxon office (a list of sales offices can be found on their webpage). The motor cost approx. 42 Euros (incl. shipping, VAT etc.).

The reason I exchanged the original BIX motor was that the Premotec motor used in the BIX makes a 'ringing' noise that I could not stop, despite my best efforts using a number of different materials to silence it. Unfortunately the noise was loud enough to be noticeable some 3 meters away from the turntable...

I found a lot of useful information on a German website http://rcswww.urz.tu-dresden.de/~cs838136/krishu/. Unfortunately most of the info on various motors is only available in German (a lot of the other information has been translated to English).

The motor is controlled by a relatively simple DC controller based on the LT1086 (google for this chip, the application is the standard voltage controller).

The stability is very good, I cannot see any speed changes when using a strobe disk and, more important, I can not hear any either. The motor is dead silent (opposite to the Premotec) and fulfills my requirements perfectly.

The motor housing is a piece of stainless steel tube with some lead to make it heavier, the pulley is made from brass.

Best regards,
Andreas

[Soundadvice]

I haven't got motor problems myself as I use a technics sl1310 mk2!

Yes I am stuck with a generic 70`s S shaped arm , however ,this is made of better materials than the 1200/10 inspite of being the same design. slack the arm bearings a touch ! it sounds livelier !

undoubtedly, a modded rb 250 will better this arm but the timing aspect of this deck (the platter assembly is so much better machined than the 1210 ) leaves rega`s td 160`s linns ( all of which I`ve owned) sound vague and woolly !

belts? the only thing I haven't tried is the origin live mod (permotec coreless) !

get yourself a classic DD trio, denon, technics sl150mk2 (I can afford one but I cant find one) similar or better, w&f due to supply fluctuation ,suspension movement ,stylus drag (this can microscopically stretch a belt and slew suspension) etc. even ambient temp range for goodness sake WILL BE A THING OFF THE PAST !

[Soundadvice]

try a linear servo regulator that uses back e.m.f feedback NOT p.w.m as this puts the noise back in that not using mains a.c. eliminates !

the premotec cl 29 3 W runs upto 24v, I would guesstimate that nominal speed means no load and max voltage !

[Soundadvice]

Try a linear servo regulator that uses back e.m.f feedback NOT p.w.m. as this puts the noise back in that not using mains a.c. eliminates !

If you dont want to build one, look through the RS catalouge,but these are on the pricey side and can handle 60w plus (like amp P.S.U`s nothing wrong with a bit of headroom), but have possibilities.

The premotec cl 29 3 W runs up to 24v, I would guesstimate that nominal speed means no load and max voltage !

Although the easy way out is to use something like an lm 317 where 2 referance resistors (quality multi turn variable) could be switched (make before break) to give you both speeds.

[ssmith]

I picked up a DC motor from an electronics surplus shop. It is Russian, very well made -- and superficially is of equal quality to Maxon and Escap motors. Very heavy, nicely finished. It cost me around $12. I have no specs for it, but the shop I bought it from said it was a 30V.
It runs all the way from 1.2v up to 32v, meaning that fine tuning the speed is easy.
To control it I use a simple laboratory DC power supply, which can fine tune the voltage in 0.05v increments. This cost me around $30.
The motor runs extremely quietly, even at full power.

My view is that with a very heavy platter and spindle weight, speed changes due to things like stylus drag should be negligable.
I am not very much into electronics, so I haven't even thought of getting some kind of chip speed controller.

Try hunting through electronic surplus shops if you have the time, otherwise contact Maxon and buy a motor direct from them as mentioned above. In the end the cost of around 42 euros is damn good.

But for a really simple (and cheap) recipe, I would look here - the Krishu.de site mentioned above.

let us know what you end up with...