Power Tube quandry

[richidoo]

My Snappers have a tube problem. The stock OEM power tubes are Groove Tubes E34Ls, made by JJ. It is an incredible sounding tube, no doubt the best sounding EL34 type available. It is a copy of GE el34, with some modifications inside to allow it to make 5W more power than standard el34s. I have tried SED EL34, and JJ KT77, neither are even close to the GT. The first batch when new lasted 2000+ hours without a problem. In the new batch, 4 of 8 have died a violent death within first 300 hours.  B+ is 570VDC. Maybe that is a little high for EL34?

Manley has been unable to devise a way to better screen the GTs. When I consider the talent of those working on the problem, it means to me that they are not screenable - they are all bad in this latest batch. How many years will it take to chew through this batch, and will the next batch be any better? Without a visionary leader to prevent the current shitty quality why should I expect the next batch to suddenly improve? Entropy is more likely to make things even worse.

Manley is now shipping all new Snappers with 6CA7EH as OEM. I have requested permission to send in the defective batch of GT tubes in exchange for the new EHs. I hope the EH tubes sound good. But I don't hold high hopes for that. Next tube amps must be 6550/KT88. Plenty of solid tubes there.

I had just convinced myself to sit tight and enjoy the music, since the Snappers do 90% of everything I want very well. The synergy with the Minimax and Altmann is awesome. But reliability must come first. I love these amps for the incredibly intimate immediate detailed sound, so dumping them is like firing a beautiful smart sexy rich horny girlfriend because of bad breath. The great amps mean nothing if I can't trust the tubes.
Rich

[miklorsmith]

Oy, that's a tough one.  That dumping the girlfriend line is an all-time classic though.   

If the first batch lasted so much longer is it possible the amp is out of spec somehow?

[richidoo]

I have considered a problem might be with the amps, but Manley places all blame on the tubes. The amps sound incredible when working, but I guess it could still be something wrong that eats tubes. If they blow up EH tubes also then I would suspect amps out of spec. Since I'm under warrantee I'm just going along with their advice for now. If the EH tubes solve the reliability then at least I am back to 100% perfect stock condition and can sell with confidence. If they sound good, then I can keep while I continue to save for step up. I can't imagine EH tubes sounding better than SED, but it is a different tube, EH 6CA7 v SED EL34. I just don't want to shell out another $250 to self-fund a repair experiment while the amp is under warrantee.

I have a set of SED EL34s on hand so I will stick them in there. I removed them after 10 hours due to unacceptable sound quality compared to the GTs. Maybe with some more break in they will sound better.

[bacobits]

Rich,
I use JJ E34L here and I do like them a lot. I had heard of GT having quality issues awhile back but that was with 12AX7.
I also thought the GT tubes were Chinese manufacture and not JJ. Jim McShane was having problems with GT quality and stopped selling them. I would expect Manley to carefully screen tubes but quality problems arise and maybe that is why they are going EH now. The winged"'C" SED are supposed to be a good sounding rugged tube. I was going to try those next.

Ahha! I see from GT's site they have quite a few variations of EL34 there not Chinese. You don't hear much about them.
Maybe they are more popular in music amps?

Den
 

[Bill O'Connell]

Rich,
 Try the new reissue Genelex KT77's, Jim McShane can match you up a quad. $200 for a matched quad is very reasonable and they sound delightful. Nothing like the ever pronounced tops of the JJ KT77's and reliability seems to very good, plus they have a deeper bottom end then the JJ's with a creamier midrange.

[richidoo]

Thanks for the tips guys! Didn't know about the new KT77s, sounds very interesting. I will check it out.

Not sure what's going on with JJ...
Rich

[Bill O'Connell]

Rich,

 I have about 10 matched quads of the Groove Tube EL34Ls from about 5 years ago(NOS)

 If you want a couple quads just let me know $80 per quad. If any go bad within the first 30 days I will replace free of charge . They graded their tubes on a number system I believe from 2-10, if you have a preferred number let me know as I probably have them.

Later,
 Bill

[richidoo]

Wow, that's great Bill!!  I will definitely get some from you. I was reading about the Gold Lion last night too. You have given me some nice choices. Thanks!!!!!
Rich

[Bunky]

Jim McShane over @ the Audio Asylum recommended SED El 34, Mullard ReIssue El 34 or Gold Lion Reissue KT77 for my soon to arrive here VTL monoblocks. It would cost alot to buy two quads of the Gold Lions but folks are saying that they sound Phenonminal. Good luck Rich....WCW III

[richidoo]

Hey Bunky, I have 2 quads of cryoed SED el34s with <10 hours on them. You can have them for  $170, half price. That's enough to get me a couple quads of those NOS GTs from Bill's stash. http://store.tubedepot.com/bsct-el34-sed.html

I'm saving up for Gold Lions but yeah they're expensive alright! 200/quad
My wife says the name sounds like rubbers. 

[mboldda1]

my consonance cyber 800's come stock with eh 6ca7eh and they are great sounding tubes.

[richidoo]

Thanks. I have read that too, they have a good rep. I'm hoping Manley will send me some of those. If not I will buy them myself eventually.
Thanks
Rich

[Bunky]

Hey Bunky, I have 2 quads of cryoed SED el34s with <10 hours on them. You can have them for  $170, half price. That's enough to get me a couple quads of those NOS GTs from Bill's stash. http://store.tubedepot.com/bsct-el34-sed.html

I'm saving up for Gold Lions but yeah they're expensive alright! 200/quad
My wife says the name sounds like rubbers. 

Hey Rich,I strained my audio funds by decideing to snatch the VTL MB-100s from out of the blue but next week i can put some more money into my Audio kitty and i will buy the two quads of Black Sable/Winged C EL 34s from you  Black Sable kind of sounds like a prophylactic also  

[richidoo]

OK cool. PM your new address and I'll send em off. Thanks
Rich

[Bunky]

OK cool. PM your new address and I'll send em off. Thanks
Rich

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