bard61 Posted May 3, 2015 Posted May 3, 2015 So last night my venerable AI500 decided to blow. Very sudden; I noticed one of the EL34s was glowing bright orange, then within 30 secs it went purple, then pop! Fair amount of smoke from the back of the amp. I've had an EL34 go bright orange before and have just replaced the quad set of valves, but never anything like this. Any idea of what's gone, aside from the tube, much appreciated. Also any recommendations for a brand of EL34, I might steer clear of Electro-Harmonix from now on...
Gordon Macfarlane Posted May 3, 2015 Posted May 3, 2015 Brad ,with smoke coming out I wouldn't power the amp again until a suitably qualified tech has given it the once over. Could be just some resistors but the mains tranny may have gone if there wasn't a fuse in the ht? line etc. I an sure others here will be able to point you in the direction of a good tech.
bard61 Posted May 3, 2015 Author Posted May 3, 2015 Thanks Gordon. Don't worry, I wasn't planning on re-powering after that show! I'm in Sydney's Inner West, pretty sure that Classic Hi-Fi in Newtown have a tech that deals with tube amps, I'll give them a call unless other SN members have other recommendations. Appreciate your response, cheers, Brad.
Equaliser Posted May 4, 2015 Posted May 4, 2015 Ouch. Worst case transformer blew and couple resistors with it. If you heard a loud bang or funky smell then it would point to a capacitor. Mind you I've seen 1000uf 1kv HV caps short and blow in front of my eyes. Very scary stuff.
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