Adcom Amp Owners Rejoice!


If you have an Adcom amp in the 535 or 555 series and you somehow manage to trip the Thermal Protection indicator, don't despair. Unless you have been seriously over-driving the amp, you may be able to solve the problem yourself. I stupidly tried to make a speaker cable change or adjustment a few months ago, and the amp died, tripping the TP indicator. I went online and found that in many instances, an internal fuse (there are generally 4 of them) could be blown.  I ordered some 4 amp fuses from Amazon (a financial mistake); they arrived a few days later and I took the top cover off of the amp to install as many as needed. First thing I learned is that you need a fuse puller to remove a fuse. Went to the local NAPA store and got a cheap one for less than $4. The first fuse I pulled was blown, but the other three were fine, and I took that as a good sign. Installed a new fuse, plugged the amp in and hit the power button....it came on as normal and I breathed a sigh of relief. I haven't actually tried to use it yet, but expect no further problems. About one year ago, I had a similar problem with my GFA-555ii amp, and paid $140 to a repair shop to get it fixed. I have no doubt that was nothing more than a blown fuse, so a valuable lesson was learned there.

discnik

They definitely are - I have three of them (GFA 555ii / 535ii / 7500), and they are all workhorses. The amp was not at fault....I had it hooked to a multi-speaker switch and tried to swap out a set of cables on the switch while the amp was on. I think that caused a short that threw the amp into the Protect mode. I considered it as punishment for violating the "Don't make any connections/disconnections while the amplifier is on" rule.

I have 2 535s and a 545 in use in my theater. They are workhorses, and now, at 30+ years I have yet to experience any issues, just that good Nelson Pass-designed MOSFET sound. If and when they go, I'm not sure what I would turn to for replacements. Or improvements, for that matter.