Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Stereomour => Topic started by: smithanh on July 23, 2014, 03:20:00 PM
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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
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And has anyone else had a similar problem with a JJ tube?
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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
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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.
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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.
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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.
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Thanks PJ
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Thanks Paul, I'll pass this on to the folks at Eurotubes. I suspect I just got a bad one.
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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.
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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.
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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.
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Paul,
I actually thought the same thing and tightened the socket, but it did not help.
Brad
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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.
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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.
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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.
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True or not that's an amazing legend Paul.
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I received the JJ2A3-40 about a month ago, ordered from Eurotubes, but with two different glass envelopes. One with a larger envelope, ceramic base with the logo on the glass, the other one is smaller with bakelite base and the logo on it. Michael of Eurotubes told me that the one with the smaller glass envelope is the new product. And he sent me a replacement direct from JJ in Slovakia, it arrived last week Saturday, with the same specification as the one already with me. Michael also told me that the 6 months warranty starts at the day I receive the replacement tube, which is very fair of them. And I don't have to send the old type back to them.
I must say that the Eurotubes is very responsible and act promptly. Maybe there are some JJ products that came from a bad batch, but with their service I won't hesitate to buy the JJ products from them again.
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I ordered a pair of jj 2a3-40 yesterday from EuroTubes. They sent me an email asking if it was going into a Bottlehead. I had mentioned in the comment area when ordering the tube that BG forum had commented positively about their business.They have had several returns on the tubes in BH gear and he's been exchanging blindly but has done enough that he can't continue to exchange. He said he can't warranty the tubes until the issue is resolved.
Eric
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The Paramour/Stereomour has been in relatively constant production for 15+ years with roughly the same operating parameters.
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My take on this is that we design amps for tubes that meet the spec of the tube we say it is designed for. If we say an amp is designed to use a 2A3, you can plug in an old stock 2A3 and it will work well. You will also be able to plug in the current production tube we supply with it, which means that that current production tube we supply also meets the spec of the original. This is also true of 300Bs in the Paramount amps.
If you buy a tube from a modern day manufacturer and it does not perform to spec in our amp, then it is not performing the same way as an original tube. I am not saying this is good or bad or that the tube is better or worse.
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Eric
I'm sorry and didn't mean for it sound like that and I really had no right to comment so I removed it
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I should also mention that I have had no contact from JJ or Eurotubes regarding this. It is not clear to me what kind of resolution might be in mind, but it will be difficult for us to assess the problem without any samples to work with.
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Looking at that statement the only one making an assumption is you. All that was said was that there is an issue that needs to be resolved.
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I just placed an order from Eurotubes for a pair of the JJ 2A3-40 tubes for my Stereomour. It is still stock and is currently running a set of Shuguang 2A3C tubes and sounds very nice. They were priced right and replaced the Sovtek stock tubes which weren't bad but the tube rolling bug hit me and so it goes...
My next acquisition may be the TJ 2A3/n version. They are about the same price. I have several sets of the TJ 300B/n so-called mesh plate tubes and love them. One pair is currently residing in my Paramounts and are astonishing. If the 2A3 is anything like the 300B then it may be a very happy purchase!
Is one better than the other? Don't know and don't care. Sometimes a change is needed to refresh the poor ears...
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I look forward to your comments. I have kind of quietly lusted after the 2A3-40s. I currently run Shuguang 2A3Cs.
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Well, I cannot believe anyone would be disappointed in the JJ 2A3-40 in any BH product amp designed for the 2A3. My review of the JJ's can be found on the Eurotube site here( http://www.eurotubes.com/eurotubes-JJ-2A3-40-Review.htm ). Paul Birkeland built my Custom BH 2A3 amp, and I am extremely happy with the JJ's as well as with Eurotubes, which guarantees their tubes for six months.
Cheers, Hank in Eugene