Jolida amp repair in and around San Francisco

Hello Folks

I recently purchased a Jolida JD-202 second hand from a friend. The amp sounded fantastic for about a week - but then around yesterday, it started making some "popping" noises. The popping more or less stopped today but the amp sounds like it has lost a LOT of it's bass. It sounds a fair bit "thinner" and flatter (the drums all sound like leather gloves being slapped against a woodblock rather than a wood stick being hit on taut leather) and appears to have lost a lot of it's audio power too (I need to turn the volume up higher to get the same sound through the loudspeakers).

I was thinking of taking it to a repair center to see if any of the tubes needed fixing- but I wasn't sure I knew any good tube amp repair folks in the city. I like in the Mission District in the city and was wondering if anyone had any recommendations they could make.

Thanks so much!
I recommend True Sound in Campbell (South of San Francisco). See:

True Sound
Nick Gowan
136 Kennedy Avenue
Campbell, CA 95008

Tel 408-370-7578
Fax 408-370-7581

Excellent repair services: "Not only do we bring the dead back to life, we specialize in refining the musicality of your equipment by selectively modifying individual elements. We also provide meticulous restorations of vintage equipment, especially valve (vacuum tube) components".
Classical Audio Service is an owner operated small business specializing in the restoration and repair of vintage high fidelity sound equipment and is located in Vallejo. The first thing to do is contact him with what your unit needs. You can e-mail Classical Audio Service at
True Sound, Scott Frankland in San Jose or L & M Services on Geneva Ave.
Is the problem on both channels or just 1?
I would recommend giving Jolida a call and ask for their opinion first.
Meanwhile, You could also ask your fiend how long he had owned the amp and if he ever replaced the tubes.
Check the manual and see if the amp has any kind of fuse protection. It might be a simple fix you can do yourself.
Search your area to see if anyone can test your tubes to verify all tubes are good.
@Hgeifman, @Crubio - Thank you so much. Those recommendations are very useful!

I was planning on calling my friend today. I don't think he had to replace the tubes - but I am not sure. I know he sent the amp in to Jolida at least once when he owned it, but I am not sure what the issue was that time.

@zd542 - the problem seems more exacerbated in one channel - but overall, the problem seems to be across both channels as the overall power output seems to have dropped.

@Timo62 - if this was a fuse problem, would the amp be working at all? I see all the EL-34 power tubes light up and glow and that means the heater circuits are working.
Mitch Singerman is the authorized Jolida repair center for the U.S. His number is 310-823-5145.
@Taters - thank you so much for Mitch's phone number. I called him and he was extremely helpful. Gave me a bunch of advise on basic housekeeping of the amp, how to bias it (since it does sound like it might have gone overbiased), how to swap tubes around etc. Incredibly knowledgeable and helpful person. So thank you for that tip!
Badri, I am glad that worked out for you. Mitch is a very nice person and very honest. I wish everyone was like that.