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Thread: VOX AC30C2 volume drop

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    VOX AC30C2 volume drop

    Hi, ever since I bought my AC30C2 I've had a variety of issues regarding noises, tubes and furthermore. Now I'm having a volume drop, like the amp is running half its power, after playing for about ten minutes. It also makes a crackling noise when the volume starts dropping. I swapped all the tubes already, but who knows, maybe one is defective? In that case, which one? Or could it be a component besides tubes?
    Thank you for your help.

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    Bent Member Chuck H's Avatar
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    You would need to trace the AC signal voltage through the circuit. If all the panel controls are working correctly the problem is likely after the preamp, so that would narrow the search. The crackling could be indicative of a bad solder connection, a bad pot, a bad tube, a dirty tube pin or socket, etc. Unless you have a signal generator and a scope (or at least a DMM) you would probably be money ahead to take it to a pro unless you WANT to learn this stuff. Which can be fun and rewarding on it's own. But if you just want a working amp a shop may be your best bet unless you have electronic bench gear and some chops because the symptoms at this time are vague without bench tests.

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    "In fact when I run into problems working on electronic circuirts, there are so many times that when I finally track it down, the source of the problem is located between my soldering iron and my seat." SoulFetish

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    Supporting Member Randall's Avatar
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    Since this is your first post, you probably have not read the sticky post about 'dreaded switching jacks'. If your amp has a Send and Return jack on the back, try plugging a patch cord between them. If this makes an improvement, your Return jack needs to be cleaned or replaced.

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    It's weird, because it WAS working fine.....

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    all the new amps are made with lead free solder,that has a tendency to fracture and most of the times leads to crackling/intermittent sounds.
    Try chop stick on joints all over the board and jacks.

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    Senior Member Pedro Vecino's Avatar
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    Your amplifier has a sliding selector on the back to bypass the loop. Sometimes they fail and do not make a good contact. It's the first thing I would look at.

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