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    High-Gain mode SP12 + PH12

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    Digdug

    Posts : 18
    Join date : 2012-10-05

    High-Gain mode SP12 + PH12

    Post by Digdug on Sat Oct 06, 2012 12:31 am

    Hello Everyone,

    First time posting. So I have the following system - Bob's ST120, Roy's SP12 + PH12, Rega RP3 with a Dynavector 10X5 and groovetracer subplatter upgrade. A pair of Paradigm studio 100's, and a Dynaudio sub250. With my old cartridge and previous bookshelves in place, I was fine running the SP12 + PH12 in low-gain mode, but now I can turn the volume up all the way and still want it to be just a tad louder. There's no distortion at all though. Still sounds very nice at full volume in low-gain mode. So I unplugged the preamp, opened it up and moved the jumpers into the high-gain position, plugged it back in and let it rip. When I turned up the sound a bit more than I had done previously (still no distortion) the left channel cut out completely, then with a little static came on a bit static-sounding and then off completely, then I turned everything off. Here's the other thing, sometimes when I use the preamp's master volume nob while music's playing I get static when I turn it each notch. I'm not sure, but the left channel going in and out may have corresponded with me turning the volume nob on the preamp. So, I put the preamp back in low-gain mode and, no real problem (except for the occasional static when adjusting the volume.) Just now I put it back in high-gain mode and it's fine, except for the occasional static when changing volume. So, any idea of what is going on here and how to fix it? Please dumb down your answers as much as possible as I know zero about electronics.

    Thanks in advance, love the power amplifier and preamp!
    Doug

    Bob Latino
    Admin

    Posts : 2374
    Join date : 2008-11-26
    Location : Massachusetts

    Re: High-Gain mode SP12 + PH12

    Post by Bob Latino on Sat Oct 06, 2012 7:57 am

    Hi Doug,

    From your description it is possible that the volume control on the SP12 preamp may have some dust in it. Dust inside any control will cause a scratchy or static type noise. Go to Radio Shack and get some contact cleaner like their > RadioShack® Anti-Corrosive Lubricant Spray. They may still carry the Caig Pro Gold spray which is a little more expensive.

    Open the preamp up and with the preamp OFF spray some of the contact cleaner on the control. It will penetrate the control. Then turn the volume control from one end to the other maybe 10 times. Your volume contol should be clean now. If you still get a slight scratch then repeat the procedure ..

    RadioShack® Anti-Corrosive Lubricant Spray

    Bob



    Last edited by Bob Latino on Sat Oct 06, 2012 4:54 pm; edited 1 time in total

    Digdug

    Posts : 18
    Join date : 2012-10-05

    Re: High-Gain mode SP12 + PH12

    Post by Digdug on Sat Oct 06, 2012 8:15 am

    Thanks, Bob!

    Do I have to take any of the components on the inside apart or just put the little straw as close to the base/shaft of the interior of the nob and and give it a few squirts?

    -Doug

    Bob Latino
    Admin

    Posts : 2374
    Join date : 2008-11-26
    Location : Massachusetts

    Re: High-Gain mode SP12 + PH12

    Post by Bob Latino on Sat Oct 06, 2012 9:14 am

    Hi Doug,

    You don't have to take anything apart. Just spray with the little nozzle on the cleaner near where the solder connections are. Maybe hold the preamp in a way so that the cleaning fluid will drip inside the control.

    Bob

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