2. amps-preamps
  3. 132537-2693

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
 
@atmasphere  Can you show me an example of a fake. I'm not sure how one would fake a tube. How is it done? Thanks
swampwalker's avatar
swampwalker
5,138 posts
 
@artemus_5 - Not to step on Ralph/s toes, but fake tubes are re-labelled modern production.  Wipe off the printing on the tube and you can label it anything you want.  Put it in a plain white box and voila...NOS goodness.  Also pulls sold as NOS.  Be VERY careful on eBay.  Most of the "NOS" tubes I bought there turned out to be junk. 
atmasphere's avatar
atmasphere
11,979 posts
 
+1 on that.

New Sensor bought the Mullard trademark so their stuff isn't 'fake' but it does not hold up like the original Mullard rectifier did in the ST-70.
trelja
3,224 posts
 
Thank you, Ralph.

I’ve seen excellent reliability out of current production Shuguang 5AR4. I think the one I use logged 7 years of steady rotation. My issue with them is that they barely reach a sonic level of adequacy. No idea on how my Sovtek holds up, as I find it unlistenable, and it has little more than break-in hours on it. JJ definitely sound the best of today's tubes that I've tried, though still not as good as vintage Mullard.  But after blowing a half dozen between my various amplifiers inside a year, I’ve grown tired of buying more.

You’re right about the ST70. I consider it a fantastic amplifier, and my Jadis (one of their best) Orchestra Reference and Quicksilver (considered their finest) 8417 both employ the same design even if Leo Fender implemented it prior to Dynaco. I’ve run the gamut on Dynaco "improvements", most of which swap the circuit for a Mullard long-tail pair. None of which improve upon the original. In my experience, presuming a person doesn’t demand more power, there’s just one sonic flaw, which takes less than $20 to address
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?
More to discover