JJ 2A3 tubes

[smithanh]

I recently ordered the JJ 2A3 tubes to replace the stock Sovteks based on many comments on this forum. They came Saturday, so i plugged them in and was very happy with the improvement in sound. Listened for several hours Saturday. Turned on the amp Monday, walked over to pick out an album, smelled something burning, and looked around to see one of the tubes glowing orange. Called Eurotubes and they said to switch it to see if it was the tube or the amp (it was the tube). The guys at Eurotubes were very helpful, but they asked if my version of the Stereomour had a slow start or not. I really don't know, can someone help? It's about 3 years old.
Thanks

[smithanh]

And has anyone else had a similar problem with a JJ tube?

[Hank Murrow]

I was using National Union 2A3's in my Custom BH amp, and switched to JJ 2A3-40's with no trouble of any kind. I find them a worthy tube and they rendered a larger stage and the scale of the presentation and dynamics improved. Seem to be more powerful, but all voltages remained the same as with the National Unions.

Cheers, Hank

[pdxgrampa]

Picked up a set @ Eurotubes today and got asked the same question.
Eddie seemed to indicate a history of arcing in some Bottlehead amps.
I searched the forum and did not find any history of that here with JJ 2A3s.
I assume he's talking about holding off B+ .
Be interesting to see if anyone here has had arcing problems with JJ 2A3s.

[smithanh]

I talked with Eddie as well. Vey helpful, but I don't know the answer to his question about how the Stereomour starts and if that could be the problem with this particular tube. Never had an issue before.

[Paul Joppa]

The "history of arcing" occurred with the direct-coupled Paramount in 2A3 form, and has been resolved with the slow-start driver implemented in the current version and available as an upgrade kit for older amps. There is NO history of arcing with the Stereomour/Paramour circuit, which is capacitor coupled and cannot generate the conditions.

Incidentally, the arcing came to our attention with an EML tube; there are a few others that do it sometimes but most tubes, including NOS and those we ship, never had an identifiable issue.

[pdxgrampa]

Thanks PJ

[smithanh]

Thanks Paul, I'll pass this on to the folks at Eurotubes. I suspect I just got a bad one.

[sharpi31]

I bought 2x JJ 2A3-40 and one failed after approx. 2 weeks use. No smell or any other warnings. I checked amp voltages and went back to my Shuguang 2A3C which have been fine ever since.

[BNAL]

I just went through to different pair of JJ 2A3-40 tubes. I think that they have a bad batch of tubes. Back to the Shuguang 2A3C that have been in use since 2007 with no problems.

[Paul Joppa]

Sadly. not all tubes have the same diameter pins. It may be a metric/English thing, compounded by the declining quality of available tube sockets. You might (if you haven't already) check to see if the "bad" tubes are merely not connecting to the socket properly.

[BNAL]

Paul,

I actually thought the same thing and tightened the socket, but it did not help.

Brad

[borism]

I had one JJ 2A3 go bad after about 4 months and Eurotubes replaced that one under warranty. The replacement tube went bad after less than one week. Again, Eurotubes honored the warranty and replaced that tube. Each time they matched the replacement tube to the one good, original one. It has been a month now and (knock on wood) everything seems fine. In both instances the bad tube seemed to lose power. Eurotubes confirmed this with their measurements. So, I agree there may be a batch of bad tubes.
However, compared to the Sovteks, there is definitely a sonic improvement to my ears with the JJs.

[Paully]

I am using the JJ 300B in my Bee Pre and love it just like people love the 2a3 but I was concerned about reliability having heard significant concerns over their octals.  Jim McShane was not shy about telling how bad the batches coming from JJ were.  I don't know if there is a feeling that QC issues are spreading or if the earlier problems were fixed.  Hopefully the problem is not widespread.  Funny how a tube manufacturer with known QC problems is still acknowledged as producing really good sounding tubes.

[Paul Joppa]

By rumor at least (I don't think anything was ever officially said) Western Electric destroyed 75% of 300Bs before they left the factory, for one fault or another. It's a tricky tube to make well. It's sad but believable that a manufacturer would let the marginal ones out rather than engage in such mass destruction, or in the expense of such extensive testing.