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Genalex GL GZ-34 Rectifier...Did I just get a bad one? Five months seems

like a terribly short lifespan. I bought it in May and spent the extra money to get a "good" tube. It sounded good while it lived. But it went in a fiery inferno last weekend.  Fortunately it only took out a fuse.

It was running in a Bob Latino VTA ST-70 Dynaco amp. It's a great amp but runs the rectifier a bit hard from my understanding. However the original tube lasted at least 3-4 yrs IIRC. I tried a SS rectifier. YUK!! I put the tube (a spare Sovtek) back in place I've had good luck with the KT-66 Genalex GL's and they have a good reputation (I think). Is this just the luck of the draw. IOW, even a new tube can have a short life span? Or is this odd? Is there any way to avoid it? I'd buy another Gennalex GL if it will last. But I can buy 2 Sovteks for the price of one GL. Sovtek sounds good too.

FWIW, The tube that failed was cryo treated. Could that make a difference in a rectifier tube? As always, Thanks for your help.
128x128artemus_5
artemus_5's avatar
artemus_5 OP
1,992 posts
 
@swampwalker @atmasphere @trelja 

Thanks for the clarification guys. Though I not a complete newbie to tubes, I don't spend much time rolling unless it sounds bad. FWIW, i ordered (& received) another Genalex Gold Lion GZ34. This is  from Jim McShane. The GL made the amp sing while it lived though it was a short life. I'm going to guess that I just got a bad one or that the Cryo treatment was a culprit or both. My previous rectifier lasted 3 yrs or so. Maybe I'll get that from this one. I'll let you know if I don't.

Trelja, did I understand you to indicate that other amps on the market  use the same circuit with a double rectifier tube?
trelja
3,226 posts
 
@artemus_5, yes, the Quicksilver 8417 monoblocks each have dual 5AR4 rectifiers, and use the same circuit as the Dyanco.  Most have converted to EL34 or KT88 operation, as the 8417 became difficult and expensive to source.  This amplifier was the first Quicksilver, and considered by most their best sounding.

However, we need to look at things in totality.  I've actually blown more rectifiers in the Quicksilvers than the Dynaco ST70, as the amps use an initial power supply capacitor too large by a factor of about 4.

The Jadis Orchestra / Orchestra Reference integrateds also use this circuit, though with solid state rectification.  And in this application, with the right tubes, the results sound exceptional.  Still, I'm a fan of tube rectification, and the sonic beauty it lends
wolf_garcia
6,744 posts
 
Great. Now Ralph has me looking for a genuine old Mullard rectifier. That's just great. Thanks man. 
atmasphere's avatar
atmasphere
12,061 posts
 
No school like the old school
artemus_5's avatar
artemus_5 OP
1,992 posts
 
@wolf_garcia 

Yeah, Me too. But I can't imagine a NOS Mullard is going to  beat the Genalex by very much in sound quality. It is fabulous. This one isn't cryoed. Maybe it will last longer. But I'll probably try a Mullard NOS. Look at it this way Wolf. A professional said we needed it. My wife will still roll her eyes. She told me last night not to change anything because it sounds really good
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