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Old 7th January 2013, 10:16 PM   #41
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I've had my geddon-esque psu running constantly for a few days, but still not listened to it. I was getting 95Vac to the motor given the 140Vac coming from the transformer and 4K series resistance. I have read that the linn motor is quietest with a 65Vac supply, so now increased the series R to 10K which has brought me down to almost exactly 65Vac.

The weird thing is that I was measuring a lower Vac after the 0.2uF cap with the higher voltage supply (about 85Vac vs 95Vac) but now that I've increased the series resistor to 10K I'm reading a higher Vac after the cap than before it (71.5Vac vs 65Vac). With about 6K series resistance I was getting similar voltages on the two phases.

Is this because my meter is rubbish, or is this as it should be? If the meter is accurate do you think I'd be better with the 6K series R and balanced voltages on the two phases, or 10K series R with unbalanced but lower voltages?

The deck struggles to start with 10K series R but doesn't need a helping hand - it gets there on its own :-)

Last edited by sharpi31; 7th January 2013 at 10:18 PM. Reason: Typo
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Old 13th April 2014, 11:54 AM   #42
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Could I use resistors to cut down the supply voltage to 85VAC If I got a transformer with 120 Volts AC output for this cloned project?
I have one toroid at 725VA with 3x0-40volts AC secodaries out.

Last edited by Mikewong; 13th April 2014 at 11:58 AM.
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Old 26th April 2014, 08:00 PM   #43
Pyramid is offline Pyramid  United States
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Default TD150 motor supply

Take a look at this regenerative PSU: Digital PSU and Tach

DDS circuitry provides low distortion, extremely accurate (35µHz steps) sine wave. Front panel selectable voltage reduction after platter reaches speed, soft start ramps the frequency to reduce "burn out" on the belt.

Can be used stand-alone or with the digital tach for quartz locked accuracy with a belt drive.
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Old 30th April 2014, 07:38 AM   #44
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Quote:
Originally Posted by sharpi31 View Post
The weird thing is that I was measuring a lower Vac after the 0.2uF cap with the higher voltage supply (about 85Vac vs 95Vac) but now that I've increased the series resistor to 10K I'm reading a higher Vac after the cap than before it (71.5Vac vs 65Vac). With about 6K series resistance I was getting similar voltages on the two phases.

Is this because my meter is rubbish, or is this as it should be? If the meter is accurate do you think I'd be better with the 6K series R and balanced voltages on the two phases, or 10K series R with unbalanced but lower voltages?

The deck struggles to start with 10K series R but doesn't need a helping hand - it gets there on its own :-)
Having a higher voltage after the capacitor is normal, you have a resonant LC circuit with the motor inductance.
I prefer to have the two windings at the same voltage as any difference causes vibration
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