repair restore classe ca300

The problem can either be (a) the protection circuit is detecting excessive DC offset on the output and shutting it down to protect the speakers, in which case the amp developed a fault and the protection circuit is working and doing its job, or (b) the amp is fine, but the protection circuit has gone faulty.

If you're not well-versed in electronics, it may be best to take the amp to a local tech. Classé can probably direct you to someone in your area. This is a common fault that can affect many / most amps. Good luck!

Try looking inside and see if there are any fuses and check them. A lot of amplifiers have rail fuses -- one for each negative and positive voltage rail -- to protect speakers against a transistor short. Usually, if only one side blows it results in a DC voltage on the output and that voltage is enough to trip a DC protection circuit.

Another thing to check is the thermal switches on the heat sink. Follow the wires and see if the connections have come loose along their path. The thermal switch breaks the circuit on overheat and activates the protection circuit. A loose connection emulates a thermal trip.

These guys have repaired a few of my Classe Sigma2 amps. Give them a call.

https://www.deltronics.com
 

I owned a Classe CA200 about 20 years ago. My suggestion is to move on and forget about it.

My suggestion is to move on and forget about it.

@ozzy62 

Right now, OP has a nonfunctioning amp that he could put on craigslist and get maybe $100 as-is. Is that your advice?