VPI motor makes loud pops when turned on & off

I had this same problem, after "upgrading" my 600rpm motor with the 300rpm kit. A LOUD snap when turning my motor off and forgetting to mute my preamp, and a lower level pop, even with the preamp muted. The situation could be mitigated, somewhat, by SLOWLY operating the switch. Either way, I found the situation completely unacceptable, so finally I got around to soldering in a snubber circuit.
I used a five watt 180 ohm resistor, and a 630V .033mF film cap I had lying around.
For those of you who may not know what a snubber is, in this application, its just a capacitor in series with a resistor, wired in parallel with the switch. Problem solved.

Joe,

Did you ever figure this out? I have one 0.68 mfd 100 VDC between the red and black across the dc motor, like you have. I also have one in series with the AC switch labeled F102KT 630PP1, whatever that means. Which one(s) need to be changed to what?

John

I tried the .0022 instead of the original .001 - it still pops so I will put the original one back in.

This motor does run very smoothly and silently.

I took apart the motor housing today and found that my motor is the 600 RPM Aries motor and not the 300 that I had guessed.
The 300 RPM motors are a relatively inexpensive upgrade from VPI..
Has anyone heard a real difference when changing to a 300 RPM motor?

Joe

Sidssp - on my motor, the .68u goes between the red from the motor and the black from the motor.
The .001 goes between the 2 wires to the on\off switch.

VPI stated to me that adding a capacitor will negatively affect the performce of the motor/SDS. "Sounds better" w/out additional cap.. So i left my set-up alone and lower to vol pot when pressing the on/off.

Joe, Mine only has one .68u in it and it has no pop whatsoever. Where does the .001 connect to? Is it in parallel with the .68u?

Joe:
I have the VPI HRX which I purchased new last year and had the same problem. I also had the VPI interconnects.
I called VPI, and while they were responsive, they didn't have a good answer to my questions.
They simply said "use the SDS to shut off" the motor after each play.
Anyway, a few months ago, I stumbled upon an opportunity to buy a pair of Nordost Quatro Fil 1.2 Meter phono RCA to RCA interconnects from a fellow Audiogon member at a steal.
Now, I get a pop only 25%-50% of the time and when I do hear the pop, it's minor. I no longer need to mute my preamp. In fact, I've had no loud pop at all since my new I/Cs were replaced.
Perhaps the I/C is the problem! I'm not suggesting you buy a new and really expensive I/C, but maybe it's worth exploring.

Grant

Motor runs fine, but still pops as before with the .001

Joe

It has (1) F.001K 660PP and also (1) .68uf which I believe is for the motor phasing. Both look absolutely new, but I guess that does not mean they are good..
I will try to replace the F.001K.

Question: Can I use a .0022 600 Mylar instead of the .001?
I ask because I have one right here..

Thanks..
Joe

The value of the cap should be .68u 400v. You should be able to find it in RadioShack. Capacitors are not very precise. Any value around .68u will work. Just make sure it is 400v or higher.

The switch to the motor is arcing. Either the capacitor at the switch is no longer functioning, or you need to use a higher value capacitor. This appears to be a common problem with VPI motor switches. I believe they recommend replacing the .001 uF cap with a .01 uF cap (you would be looking for a high voltage ceramic cap), but I am not sure so please check with VPI.