2. amps-preamps
  3. 1347827294

Joule-electra LA-150 Mk 2 dead

Went to play LP's the other day-no sound at all thru the preamp. All tubes are working on the Fosgate Signature phono pre-amp, but the two 6em7's in the Joule pre-amp are burned out.I find it odd that both tubes would burn out at the same time. CD playback is fine so CD player, speakers, amp are all ok, everything is connected properly. Any idea what would have made those two pre-amp tubes burn out silently? No pop or bang was ever heard-one day the phono chain was playing fine-next day zippo. Any help would be appreciated. I ordered two new tubes but am hoping nothing in the circuit was fried.
mrmitch
marakanetz's avatar
marakanetz
5,473 posts
 
Good tube design is the main reason why tube(s) 'die piecefully' without affecting surrounding circuit components.
dob
577 posts
 
" Any idea what would have made those two pre-amp tubes burn out silently? No pop or bang was ever heard-one day the phono chain was playing fine-next day zippo"

I can only join Marakanetz opinion that the answer lies in well thought design of the power supplies. My hat off to Jud Barber....but most of all for the pleasure his preamplifier ("300") gives me during listening to the MUSIC!!!!
atmasphere's avatar
atmasphere
11,594 posts
 
Did the tubes loose their vacuum? Do they still light? What is the nature of the failure?
mrmitch OP
359 posts
 
Thanks guys, I think Marakanetz is on the right track and I trust his opinion after seeing his threads and replies for years here. Dob, have to agree about this pre-amp, its wonderful,better in almost every way from the Conrad Johnson I had before. Atmasphere, no theyre not lighting, just received two new tubes so will try them out today. All the other components work fine but when playing LP's, dead silence-no hiss, no pops, no crackles, nada. Hope its just the tubes, will see later today. Thanks again guys!
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