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-   -   DC Motor Shunt Reg (http://www.diyaudio.com/forums/analogue-source/139868-dc-motor-shunt-reg.html)

Salas 5th March 2009 07:25 PM

DC Motor Shunt Reg
 
2 Attachment(s)
A friend with a Pink Triangle TT and Origin Live DC motor + OL PSU was experiencing frequent RPM slowdown drift after playing some LPs. He had to trim his PSU all the time. He asked me to devise some PSU for him. I did. He actually made it, and he reports excellent stability over long time plus top sonics. Speaks about strong gains in image size, sweetness, pitch stability and authority. He is raving so much that I thought I better show it here for anyone interested. Don't ask me more, he lives far away on an island and I can't confirm his experience first hand.
He actually used a LM317 regulated 12V DC 1.5A input to my shunt reg as I asked him to do, and leaves the reg on almost at all times, since he gets added sound benefits after an hour or so. He actually watched the voltage stability and compared it to the OL PSU. The new reg is measurably superior for voltage stability he says, both by itself through time, and after playing LPs, as well as when spinning 220g vinyl and watching the voltage when the motor actually consumes.
Anyway, here it is. Try it out if you fancy. Its not a thoroughly checked out application by me. So I show it with caution. The pre regulation is part of the recommended circuit. You may use a well stabilized 12V DC 2A wall wart or brick PSU even. If there is noise in such a device (you can check with oscilloscope), better make a typical LM317 reg with 12V output and put it in a remote box along with mains trafo and rectification away from the TT. The shunt reg's Mosfet and Darlington need a 1C/W sink.

Salas 5th March 2009 08:13 PM

P.S. When someone trims for 33RPM and 45RPM using a stroboscope, he can use 2 trimmers and with a switch, employ one or the other, for instant RPM flip.;)

Salas 23rd October 2009 03:13 PM

Lil Maxon reg
 
3 Attachment(s)
This time a shunt reg for the little Maxon was made. Used with an LM317 pre reg and monitored for 15 days. Does not move a hair of Vout or rpm on a modified Walker CJ55. That assortment needs 4.85V for 33rpm on the stroboscope. Its run at 300mA CCS for a Maxon like the one Origin live used to name DC100 (Maxon order no: 110191) its an A-Max 26mm. This reg will do for anything needing over 4V DC or a bit lower. Less it can't due to the Mosfet Vgs limit. Chuffed for sonics and tempo. The whole combo is a success. What an upgrade from AC motor!

P.S. You have to trim RPM with an actual vinyl disc on the platter as the cart is reading with your preferred tracking downforce.

Salas 15th November 2009 04:35 AM

We have tried MJE350 in the parallel Mosfet's place later on and it worked fine for less than 4V by the way. So the application's scope widens to more pulley, belt, diam. sets.

mthoi 9th June 2014 07:55 AM

Hi Salas,

I am keen to use your schematic to build a replacement PSU for my michell gyro SE. I measured the output of the existing power supply to approximately 9.8VDC.

Do I need to make any changes to the input DC voltage and values of the components?

Tx for your assistance.

Mark Kelly 9th June 2014 08:27 AM

Origin Live doesn't use a constant voltage supply, so claiming your supply has "better voltage stability" is a nonsense.

Salas 9th June 2014 04:02 PM

Quote:

Originally Posted by mthoi (Post 3955628)
Hi Salas,

I am keen to use your schematic to build a replacement PSU for my michell gyro SE. I measured the output of the existing power supply to approximately 9.8VDC.

Do I need to make any changes to the input DC voltage and values of the components?

Tx for your assistance.

Hello

You would need 4 red LED. 18V raw DCin also. (sch. #2).

Salas 9th June 2014 04:06 PM

Quote:

Originally Posted by Mark Kelly (Post 3955646)
Origin Live doesn't use a constant voltage supply, so claiming your supply has "better voltage stability" is a nonsense.

Quote:

Originally Posted by Salas (Post 1764870)
Anyway, here it is. Try it out if you fancy. Its not a thoroughly checked out application by me. So I show it with caution.

All he reported about the actual application of the PSU are described in post one. He had the OL "standard" motor and PSU kit if that helps.

mthoi 9th June 2014 05:24 PM

Hi Salas,

Thank you for your feedback.


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