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Repair and disassembly guides for guitar amplifiers.

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lost over half the volume after changing tubes

I replaced the tubes in my Peavy VK112 and lost over half the volume on both channels, I replaced the new tubes back to the original and still have no volume.

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@shuffy you replaced all tubes? why? what happened that made you change them?

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I had the amp for over ten yrs., just figured it would help upgrade the tone.

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@shuffy not knowing what has happened to your amp leaves a few possibilities. Blown power transformer bad screen resistor, blown diodes, blown preamp etc. you will have to do some checking and post images of what and where you check. Use this guide for that. It will allow us to see what you see. Let us know if your tubes glow orange or if they get bright red,. That would indicate a thermal runaway caused by a loss of the bias voltage. Power down with the amp in play mode (standby on ) and let it discharge for at least 15 minutes. Then use an ohmmeter and connect it from pin 4 of tube V4 to pin 4 of tube V5. You should get around 700ohm's resistance. If so your screen resistors are okay. Here is the schematic for your amp for you to check. Peavey VK112 schematic

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CLIFTON HAYSLIP will be eternally grateful.
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