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Topic starter
01/07/2006 11:07 pm
Hey all,
I was hoping someone could help me with an amp problem. I'm having problems with the volume fluctuating. I'll be playing and all of the sudden it seems like I lose gain and the volume decreases very noticably. It will eventually come back up, but this happens over and over. I've tried different guitars and cords, so I'm 100% sure it's the amp.
The amp is a TECH 21 Trademark 120. It's a solid state amp w/ reverb and 3 channels. 120W through 2 12's. It seems to do it in all three channels regardless of whethor I'm using reverb, how hard I'm driving it, etc. Any ideas?
01/07/2006 11:13 pm
Usually something's loose. You've ruled out the guitar and cable. Could be the jack in the amp, a worn or dirty pot that's intermittently making poor contact, or a loose connection somewhere along the signal chain. In tube amps, socket connections often get loose or dirty as well.
"A cheerful heart is good medicine."
Topic starter
01/07/2006 11:19 pm
Usually something's loose. You've ruled out the guitar and cable. Could be the jack in the amp, a worn or dirty pot that's intermittently making poor contact, or a loose connection somewhere along the signal chain. In tube amps, socket connections often get loose or dirty as well.
Is there any easy way to troubleshoot the jack and the pots? I've got 18 pots on this beast! (although I can probably rule most of them out: this problem happens on all 3 channels, so the only possible culprits could be the final pots [master volume, etc] that aren't associated with a channel, right?)
01/07/2006 11:34 pm
Yep. Wiggle 'em and see if you can bring on or fix the volume problem that way.
"A cheerful heart is good medicine."
02/07/2006 12:15 am
This seems to be a common problem with the Tech 21 amps. Oxidation in the effects loop. My TM30 does it too, but I found this tip on Harmony Central from someone with a TM60:
Daer Tech21! I am the proud owner of a TM60. It has worked well untill now. The other day when I was jamming with some friends I got a sudden loss of volume. I tried with other guitars, but the same loss of volume occured. Have you got any idea of what could cause this? NB! I am not going to try to repair my amp myself! Mvh Henrik Xxxxxxx. Norway. "
"Dear Henrik,
Thanks for your inquiry. That sounds like dirty Effect Send and Return jacks... even if you don't use them, the signal always passes through. So if the contacts oxidize (possibly from a humid environment), there will be an interruption of the signal.
You can check whether this is the cause of your cut-outs by running a short guitar cable from the Effect Send right back into the Effect Return (a sort of "jumper") to open the jacks. If the amp sounds fine that way you'll know you only need to spray a little bit of DeOxit or similar electronic component contact cleaner in the jacks and then jam a 1/4" cable plug in and out a few times. That usually does the trick.
Regards,
Lloyd Schwartz, Product Manager
By the way, I've sent several emails to Lloyd and he always replies within a couple of days. Excellent customer service.
"Everybody got to elevate from the norm."
Topic starter
02/07/2006 12:32 am
Thanks for the tips, guys! I'm going to try your suggestions poste-haste.
03/07/2006 12:07 pm
Also check the speaker plug and jack.