JJ 2A3-40 currently not warrantied for BH amps..other recommendations?[resolved]

[HiFiC]

Created an account here on the forum a few years ago when I built my Stereomour; hard to believe this is my first post!  Anyhow, one of my stock Sovtek tubes seems to have bit the dust.  I can still hear faint music out of that channel, and when I swap the tubes between channels, the problem is replicated on the other side.  So must be a bad tube, right?

After reading up on the 2A3 tubes that are readily available for less than $250/pair, I had settled on the JJ 2A3-40 from Eurotubes.com.  Sounds like a fantastic tube that met my budget, and Eurotubes is just a couple hundred miles away from where I live in Seattle.  Gave them a ring to ask a few questions and put in my order, and was disappointed to find out they currently aren't providing a warranty for 2A3-40's that are going into Bottlehead amps due to consistent problems when paired with the Bottlehead.  Bummer!

I'm not ready to shell out a couple hundred bucks for a potential unwarrantied tube failure, so looking for recommendations on other tube suppliers.  The Shuguang Treasure 2A3-Z is probably #2 on my list, followed by the EH Gold.  Open to strong opinions from others on tube selection.  Which tube retailers do people trust and receive good service from?  The Tube Store?  Tube Depot?  Elsewhere?

Thanks!
Chad

1/8/2015 UPDATE:  All concerns have been resolved due to discussions between Bottlehead and Eurotubes!  Eurotubes is once again providing a warranty on their JJ 2A3-40 tubes being installed in Stereomours and Paramours.  If I understand correctly, only the early Paramount without the soft-start circuit is still in question and is being investigated by Bottlehead, Eurotubes, and the JJ factory.  See page 3 of this thread for photos of JJ's now installed in my Stereomour!  I'm loving them.  Woohoo!

[Doc B.]

Did Eurotubes give a specific reason for the lack of warrantee? The only issue I am aware of regarding any specific tube was several years ago, had to do with EML tubes, not JJs, and had to do with the Paramount in direct coupled configuration and not Stereomour. It was addressed to both our and EML's satisfaction with the soft start circuit we now employ in that amp.

Seems like Eurotubes would want to let us know if they are having problems, but I have not heard from them.

[johnsonad]

That doesn't make sense. Your amp is cap coupled no DC. The BH team will chime in but it's probably an odd ball seller unless there is something going on I'm not aware of and again, the Bh team will chime in.

Dan beat me to the reply button!

[mkane]

    I'll keep an eye on this thread.

[HiFiC]

Only explanation I received was that they had received an unusually high number of returns due to failure in Bottlehead amps over the past year or so, and they didn't know why.  I had seen a few references to that on the net, but it sounds like they've had more than just a few failures.  Maybe the 2A3-40 is spec'd a bit differently from the classic 2A3 design and isn't compatible with certain 2A3 amp designs?  I have no idea.  Pure speculation on my part.  That would be great if they'd be willing to work with you, Dan, to determine what the issue is, if there is indeed an issue.  I'd be happy to suggest to them that they contact you if you're up for that.

In the mean time, though, any recommended tube retailers, or retailers to avoid?  I couldn't find any local Seattle shops that stock the 2A3.

Did Eurotubes give a specific reason for the lack of warrantee? The only issue I am aware of regarding any specific tube was several years ago, had to do with EML tubes, not JJs, and had to do with the Paramount in direct coupled configuration and not Stereomour. It was addressed to both our and EML's satisfaction with the soft start circuit we now employ in that amp.

Seems like Eurotubes would want to let us know if they are having problems, but I have not heard from them.

[braubeat]

antique electronic supply has these tubes. Probably cheaper too.

michael

[borism]

I had 2 JJ 2A3-40 tubes fail this year in my Stereomour. Both were under warranty and after being checked out by Eurotubes were replaced. One tube failed after 3 months and the replacement tube failed after 1 week. Since then, the second replacement tube has performed perfectly for almost 6 months now. I believe there may have been a bad batch of these tubes.

[Doc B.]

What was the failure? Did you lose gain? Did the tube get noisy? Or was it more dramatic, like filament failure or a short? Was it the same thing both times?

[Paul Birkeland]

I think the "high number of failures" in Bottlehead amps may simply be the lack of other 2A3 amps available at the moment.  A Google search of "JJ 2A3 reliability" shows some other issues in other amps.

The Stereomour's operation is nearly equivalent to the Paramour monoblocks, which go back a very long time (more than a decade).  If the circuit was to blame for tube failure, we certainly would have expected it to take less than 13 years to develop.  Additionally, the JJ 2A3-40 boasts a higher maximum plate voltage rating and a higher plate dissipation rating. 

We are happy to work with Eurotubes or JJ in this matter, but so far we haven't been contacted, and there hasn't even been a mention of what the failure mode is. 

-PB

[Doc B.]

Paramour goes back nearly 15 years. I think PJ and I started working on that one in 2000 or so.

[Doc B.]

OK, Josh did a little research and this exact same story came up once before, same story, same players. And I said exactly the same thing then - we will work with Eurotubes to determine why their tubes are failing if they want to work with us, but we can't resolve a problem if no one will say what the problem is. There are plenty of other 2A3s out there. We've been making the Paramour/Stereomour since 2001 or so and the Sovteks we have been supplying now for several years have proven to be good sounding and exceptionally reliable in the Stereomour. I have also use Valve Arts, TJs, RCAs, Ken Rads, GEs, Sylvanias, 2A3Hs, single plate Raytheon 2A3s worth a couple thou a pair, and others I'm sure I'm forgetting, all with great results.

[borism]

What was the failure? Did you lose gain? Did the tube get noisy? Or was it more dramatic, like filament failure or a short? Was it the same thing both times?

Both times the same failure occurred. The tube would lose gain and the center image shifted towards the opposite side.

[Doc B.]

OK so this is not some dramatic failure like an arc-over. Do you happen to know if Eurotubes did any kind of postmortem on the tubes, like measuring transconductance or measuring filament resistance?

[borism]

Yes, they did and confirmed what I heard but I don't recall them telling me the exact measurements.

[Hank Murrow]

I have been using the Eurotubes JJ 2A3-40's in my custom BH stereo amp for two years now and they are still singing sweetly with full power. I haven't asked Paul Birkeland yet if my amp has the soft-start circuit or not.

Cheers, Hank