Power Tube reliability

[Luthierwnc]

I'm in the spark-testing phase of a new 50-watt build. While I was messing with the preamp lead dress, one of the new Tung Sol 6l6's red plated. I saw a little smoke, looked at the tube and hit the switch on the variac (I may have also said something I won't repeat here).

In the post-mortem, the connections were good, the bias voltage was on the nose and the other tube was right on spec for volts and draw. I swapped tubes in the sockets and the survivor was fine. The red tube died. I am using 500R screens and thought of bumping that up to 1k. I have 5k6 swampers on the grids.

This is the second time I've had a new production power tube burn-out within a couple hours of installation. The other was a JJ 7591.
What has been you guy's experience with modern post-Soviet bloc power tubes? When it worked it sounded fine and the current draw was right on the money. I got them from a reliable vendor. Also, if you have any recommendations for someone who really burns the snot out of them before shipping, mention that too.

Thanks, Skip

[heisthl]

I've had trouble with 2 different Svetlana's lately in the same senario, first time you push the amp hard an output tube fails, small puff of smoke, no damage to the screen resistor but the chrome getter has clear areas and after setting overnight the tube turns white inside (vacuam breech). As much as I hate to say it I may be going back to "late distortion" Sovteks (or the EH equivalent), rationalizing that the change in tone is made up for by the reliability.

Anybody like the Chinese 6L6es? I just bought some cheapies from TubesandMore to play with.

[stoo]

I've bought several set of o/p tubes from tubetramp (Terry Kilgore) and have had ZERO failures...so far He asures everyone he burns 'em in before he ships!
Stew

[stelligan]

Henry,

I have a couple sets of Sino 5881 tubes from TubeDepot that were uber cheap and matched to the gnat's ass. No failures yet, but like you mention perhaps a bit tone challenged. They have been running at high voltages in that Son O' Boogie for quite a while.

Dave

[Luthierwnc]

With the resurgence of tube manufacturing, I thought by now one of them would have found a niche as the go-to quality brand. For the time being, they seem to be trying to out-retro each other. Hauling iconic brand names out of bankruptcy won't help long if the products don't deliver. Even guitar players will figure that out eventually

In my case, it is tough to develop much customer loyalty when you go 0-for-1 with a catastrophic failure. I can't rule out that I did something to incinerate that tube but it sure looks like a bad un.

sh

[Tonegeek]

Same story here. Just yesterday a tube died on me. I turn the amp on, and after 1-2 minutes, no current flows. Swap sockets, same tube fails after 1 minute, so its not the amp. this tube was only 2 weeks old. This is 3 out of the last 5 I have had - All JJ EL34 from AES. I am going with Eurotubes next order as I hear he burns them in. BTW none of the tubes red-plated, they either got microphonic in the low end, stopped conducting, or did the rice crispies snap, crackle, pop.

[heisthl]

I've bought several set of o/p tubes from tubetramp (Terry Kilgore) and have had ZERO failures...so far He asures everyone he burns 'em in before he ships!
Stew

Is there a website? TubeTramp.com doesn't work

[Structo]

Is that the same guy as Sarge?
If it is I don't think he has a website per say to order from.
You have to email him or call.

[Structo]

terry_kilgore2003@yahoo.com

[bnwitt]

I've had trouble with 2 different Svetlana's lately...

Were those the newly branded Svetlana tubes or the original winged C Svetlanas?

[heisthl]

The new ones - the top of the glass is slightly different

[skyboltone]

I had a Sovtek 6L6WG? do the identical recently. Irratating. It's the "matched" bit that gives me the shivers though. I think they got the receptionist hauling tubes outa the case and marking pairs with a pen. Matched to what? Not each other that's for sure.

[heisthl]

Sorry to hear that about the Sovteks, I've never had one fail and thought that might be the way to go. Are Ruby's any good these days?

[philmanatee]

I talked to Terry today and he's sending me a pair of chinese 6L6gc's that he said sound great and are very stout. I'll report back after I abuse them a bit. He told me he hasn't been able to destroy any of them yet, and they sound like an RCA blackplate, he hasn't steered me wrong yet. Phil

[odourboy]

I talked to Terry today and he's sending me a pair of chinese 6L6gc's that he said sound great and are very stout. I'll report back after I abuse them a bit. He told me he hasn't been able to destroy any of them yet, and they sound like an RCA blackplate, he hasn't steered me wrong yet. Phil

How much $$$ for a pair?