Tube Questions

Gerry E. · 1808

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Offline Gerry E.

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on: June 20, 2014, 06:47:16 AM
Hi:

I was using JJ 300Bs in my BeePre and Sophia Royal Princess in my Paramounts.  Last week, I was able to get a real good deal on a used pair of EML solid-plate 300Bs.  I took the JJs out of the BeePre, moved the RPs to the BeePre and put the EMLs in the Paramounts.

The problem is that RPs just sound better to me in the Paramounts than the EMLs.  At twice the "retail price" they should.  I could try switching the RPs back to the Paramounts and try the EMLs in the BeePre but that was never approved.  A related BeePre forum thread just kind of died out.  Any more thoughts on this?

Second question, can someone confirm that I can use the adapters in the link below to replace the 5670s in my Paramounts with 6SN7s without any changes to the Paramounts?   My motivation for this?  I believe there will be less gain, which for me would be a good thing because I have a very limited usable range on my BeePre volume control.

http://www.ebay.com/itm/261429844163

Thanks!

Gerry                       



Offline RPMac

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Reply #1 on: June 21, 2014, 04:03:24 AM
Gerry, If I'm not mistaken, the issue is with the EML mesh-plate 300B. Johnsonad is using the solid-plate EML 300B in his BeePre. For another flavor, you can try some 6A3's. PJ's magic in the power supply makes my BeePre dead quite.



Offline Gerry E.

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Reply #2 on: June 24, 2014, 09:13:35 AM
Gerry, If I'm not mistaken, the issue is with the EML mesh-plate 300B. Johnsonad is using the solid-plate EML 300B in his BeePre. For another flavor, you can try some 6A3's. PJ's magic in the power supply makes my BeePre dead quite.


Hi Robert:

Thanks for the reply.  I thought the EML mesh-plate issue started with the Paramounts.  As for the BeePre, I believe the issue with the EML solid-plate's is the 1.3A filament current (the mesh-plate is even higher).  Here's an important quote from PJ from another BeePre thread:

"Ignoring the other variations as above, you might think you could say that a 1.3A tube will work. But you can't say a tube model with 1.3A +/-0.5A current draw will work - half of them will draw too much current."

BTW, is the 6A3 a plug-in replacement for a 300B without any mods to the BeePre? 

Gerry           



Offline RPMac

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Reply #3 on: June 24, 2014, 09:47:28 AM
Gerry, of course PJ is correct. I found where Aaron changed some resisters to get the EML's to work properly.

I use the 6A3 as a plug-in replacement.



Offline Gerry E.

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Reply #4 on: July 22, 2014, 06:01:15 AM
UPDATE - I solved my problem with the EMLs.  I sold them and acquired four pairs of used, reissue Western Electric 300Bs!  Long story but I was in the right place at the right time and got a very good deal on the WE 300Bs.

The eight tubes are made up of two matched pairs (1999 and 2005 date codes) and a matched quad (1998 date codes).  They all came in their fancy wooden boxes with all original paperwork including test reports.

Besides the obvious, this was a good thing because not only did the EMLs not sound as good as the Sophia RP 300Bs in my Paramounts, the Sophias had this odd extended warm-up ringing in the BeePre.  I know some people use those red/orange damping rings (lab weights) on their 300Bs in the BeePre and this may be a good example why.

If I could have reversed the tubes - EMLs in the BeePre and Sophias in the Paramounts then I wouldn't have a problem but as we know, you can't use EMLs in the BeePre without modifications.  So, how does the matched quad of WE 300Bs sound in the BeePre and Paramounts?  I wouldn't call it a night and day difference but they just have an overall smoothness that even the Sophia Royal Princess can't quite match. 

BTW, say what you want about the reissue WE 300Bs but all 8 tested between 86 and 88 on my TV7 tester (where 58 = 60% level).  Considering that they are all used and made as much as 7 years apart, that is what I call consistency and quality control!  Those tests results are better than most brand new 300Bs test.   Too bad they are not making them anymore.

Gerry

P.S. I know this is a BeePre thread but could someone answer my Paramount 5670/6SN7 adapter question?  Specifically, with the adapter, can you sub 6SN7s for the 5670s in Paramounts without making any changes?  Thanks!