Okay, so I got a silverface Concert Lead head off of ebay back in November, and from the get-go I loved it. Great tone, lots of power, etc. However, round about mid-March, channel 2 (reverb channel, my choice as I'd rather have spring reverb than onboard distortion) suddenly (like, in the middle of band practice) loses a lot of its power and starts sounding noticeably thin and quiet compared to what it had been initially. For a while I just used the other channel, as I couldn't afford to take it in to the local tech just yet. However, it seemed to me that that channel started to loose power as well, and I had to run it with the volume maxed to keep up with my other head (Peavey MX Flite Case) on 5, whereas previously I'd been able to run them at the exact same volume setting and get about the same output power (note, when running both heads together, each was powering a 16 ohm 4x12, either a Peavey VTM or a Marshal JCM 800, and when used alone, each head would be powering both cabs together for an 8-ohm load. I checked all impedances with a multimeter).
SOOOO, about three weeks ago, I took the Concert Lead in to the only music store in town that has a consistently available amp tech. I was a bit hesitant to do so, as he had a poor track record of working with my gear--- I've had the MX head in his shop at least 4 times since I bought it (about 3 years ago) and sometimes he has taken up to two months to get it back to me despite the repairs he made being quite minor. I've never met the guy in person, as he just stops by the music store once or twice a week to pick stuff up and drop stuff off. So I described to the owner of the store what I wanted done with the amp--- that I wanted the 2nd channel checked, all the caps checked, the worn-out power chord replaced or repaired--- and he notes it all down and I leave, hopeful despite the odds. Today I picked up the head, and while the power chord had clearly been repaired, when I went to try it out, the 2nd channel still had the same noticeable weakness of volume and thin tone, while the 1st channel--- though tonally exceptional as it always was--- had to be at 10 to produce anything even approaching the volume that it once produced at 7 or 8 or even 6 (I do have pretty high volume expectations, or maybe I'm losing my hearing).
It is worth noting that prior to putting this amp in for work, I did some research and discovered that it had been at least moderately modified at some point. Someone had put an LED in the front (right in the middle of the O))) in the logo), and the light in the switch does not work. And someone also removed the circuit breaker switch on the back and replaced it with a fuse.
I'm pretty new at the electronics thing and am still learning a lot of the basics about how amps work and how to diagnose them. If anyone here has any ideas as to what my problem(s) could be I would appreciate it. Is there anything I might be doing wrong? Am I being an ass by dismissing the tech when i may be the one at fault?
