Author Topic: JJ 6L6GC versus RCA 1960's 6L6GC  (Read 3474 times)

shrinkmore

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JJ 6L6GC versus RCA 1960's 6L6GC
« on: April 08, 2007, 09:03:07 AM »
The comparison of these two tubes came up on another thread where I mentioned that my system was sounding harsh in the high end.  It turns out that this is largely due to the output tubes being worn out in my BAT-VK5i pre-amp; although some harshness remains.  While I was rolling the eight 6DJ8's in the output stage, I compared the RCA NOS 6L6GC's Blackplates with the new JJ's for the power stage.  When I initially put in the JJ's I thought, "Wow these don't sound so bad, I wonder what it would be like to have sex with Angeline Jolie..."  (The latter type of thought just goes through my head now and then.)  There seemed to be a definition in the base that was not there before.  However, I noticed what I thought was a slight loss of detail and some los of forwardness in the presentation.  Then, when I put the RCA's back in, it was extremely clear that they are vastly superior in terms of detail and definition and the previous loss with the JJ's was much more than slight; although the RCA's are also responsible for some of the harshness, or at least increasing it with the increase in detail.  I guess this is often the case, increased detail sometimes includes some hash in the high end.  In any case, the RCA's were like lifting several veils and will remain in the preamp.  I will be pursuing getting rid if the remaining harshness and any suggestions are welcome.  I may try the NOS Tung Sol 5881 in the power stage, as these are commonly used and coveted for this pre-amp.

By the way, this is a pre-amp and is not Push Pull (PP) and does not have bias adjustments.

Offline Carlman

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JJ 6L6GC versus RCA 1960's 6L6GC
« Reply #1 on: April 08, 2007, 12:22:17 PM »
I used some RCA black plate 12AU7's in an Eastern Electric Minimax tube preamp.  Those were the bomb.  Bill at Morningstar recommended them to me.  I hope he chimes in here because he has an excellent ear an knowledge of tubes.  

The preamp was on loan to me so I returned it with the wonderful tubes still in it.  The RCA's were not for sale... figures.  ha.  But Bill supplied a few tubes to roll so I could experiment and see what I liked best.  I thought the RCA was from the 50's though.  There were some other obscure ones he sent also... from his private stash.  It's a rare priviledge to get to do that... thanks again, Bill.

Anyway, I have tried some JJ Tesla tubes in 6922, not sure if that's the same thing as "JJ"... I didn't care for them compared to Amperex.. just kind of boring.  Not bad, just didn't blow up my skirt. ;)

-C
I really enjoy listening to music.

Offline bpape

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JJ 6L6GC versus RCA 1960's 6L6GC
« Reply #2 on: April 08, 2007, 02:31:05 PM »
I've rolled a few things through my preamp.  I too ended up with 50's/60's RCA BlackPlates.  IMO the best combination of things you can ask for from a tube.

Bryan
I am serious... and don't call me Shirley

shrinkmore

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Yow!
« Reply #3 on: April 08, 2007, 03:08:04 PM »
Oh my god, a consensus of 3 from audiophiles!  We're near the end of time. :evil: