hifi engine

cyrus mains hum solution?

Before I give up and stick it on eBay, spares or repair, does anyone have a clue what may be the cause of standby mains hum on a cyrus lll amplifier? It is so bad it blew one of our test speakers.



Chriquet's picture

cyrus mains hum solution?

Check the +/_ 15 volt regulators (LM317/377 from memory) They fail.