Crackling noise, not tube or pots

knockoutpie · #1 06-13-2011, 04:58 PM

I have a carvin R1000 and it's been an awesome sounding amp. However I have found that while playing it has begun to switch between either normal volume and a boost, or it will switch between normal to a lower volume. it is hard to tell and its different every time I use the amp. But it switches between louder and not as loud. Also when I play low notes it will crackle through the high end speaker. The crackle does not move to the beat of the bass or speaker, it is as though it is it's own independent signal. Messing with the xover does not fix it so it is the amp not the frequency in the speaker, unless the xover is not working properly. And I've tried two high end speakers and they both do it. Any ideas as to what the problem is? I've also tried different basses. I attached a sound clip of the crackle. You can hear it well at the end of the clip, the fuzz is the bass not being picked up, but the crackle is clear. I cleaned the pots, but it is possible I didn't do a good job, and I tried wiggling the tube to produce sound and didn't get anything.

JimmyM · #2 06-13-2011, 05:02 PM

Wiggling the tube tells you nothing. Get another tube and swap it out. Chances are that's the problem...it's pretty common for the tube to be the cause of that crackling. Always the very first thing you should do when you have a problem with an amp that has tubes. If not, take it to a tech.

knockoutpie · #3 06-13-2011, 06:49 PM

It's a preamp tube. Is that still the most possible? I'm going to try it anyway thank you.

JimmyM · #4 06-13-2011, 07:07 PM

Absolutely it's the most possible. Other things could be causing it, such as a loose solder, but the most likely culprit and easiest to check first would be the tube. And if it's not the tube, at least you'll have a spare when you get the real problem fixed.

knockoutpie · #5 06-13-2011, 08:05 PM

haha So I got a new tube, and I'm glad I did the amp sounds ten times better now, but, the noise persisted. Then I looked at the back of the amp and there were three buttons I never press, ground lift, direct in, and bridged. Once I hit the direct in the noise stopped. When I turn it back on the noise is gone. It was just a dirty button. Now I hope the tube fixes the volume problem, if not I'll try something else but I think it will. Thanks JimmyM

JimmyM · #6 06-13-2011, 08:13 PM

LOL! Well maybe you should get a can of Deoxit and clean all your jacks, switches and pots. Glad my advice "helped"