Input Tube Adaptor in a Non-SinglePower Amp?
Nov 12, 2008 at 6:44 PM Thread Starter Post #1 of 84

mourip

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I am really enjoying trying different tubes in my Extreme. My favorite so far is a Bendix 12au7 with some Tungsole 6998's.... alive and in Technicolor!

I have a question. Has anyone tried using one of these adaptors in another brand of tube amp to replace a 6SN7 driver tube? I am thinking of getting another single ended amp like a cary 300SEI or a Tektron for my K1000s. It would be fun to also roll some different input tubes using the SP adaptors. Logic says that this should work or at least not break but maybe I am missing something.

Thanks...

Paul
 
Nov 12, 2008 at 7:55 PM Post #2 of 84

Gollie

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This is a question that maybe SACD Lover or Skylab might be able to answer but I would call Mikhail for clarification. I don't think an Extreme SLAM model is offered and I don't really know why.

I would just call Mikhail. Every time I talk to that guy I feel like learn something new and interesting about how these wonderful amps are put together.
 
Nov 12, 2008 at 8:08 PM Post #3 of 84

takezo

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it will only work if the amp's power transformer is up to the task of
the handling the specs of the tube being used... otherwise, you'll
toast your power transformer.
 
Nov 12, 2008 at 9:27 PM Post #4 of 84

nikongod

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with other amps, it REALLY depends. some will work, others will not.

If its an effort to use a 7n7 or 12au7 instead of a 6sn7 for reasons of availability/NOS prices, the odds success are strongly in your favor. The 7n7 is EXACTLY the same as a 6sn7 with different base. The 12au7 is electronically a LITTLE different (very slightly) and could occasionally cause problems.

When you get to the point of trying to switch EVERYTHING about the tube things can get weird really fast.
 
Nov 12, 2008 at 10:55 PM Post #5 of 84

Skylab

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Yeah, I would be very cautious about this in general - one of the really great things about Singlepower amps is they were designed with this tube flexibility in mind. Few amps are.

HOWEVER, if you want a great alternative to the 6SN7 you can use with adapters in any amp, try getting some 6F8G's (VT99's). These are electrically equivalent to the 6SN7GT, but require an adapter due to the different pin out and the use of the grid cap. You can get adapters on EBay for $25/pair, and 6F8G's sound awesome, look cool, and cost WAY less than 6SN7's. I got a pair of Tung Sol Round-Plate 6F8G's for $50 - the 6SN7 equivalent would cost $350/pair.
 
Nov 13, 2008 at 12:12 AM Post #6 of 84

sacd lover

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If you use a sub that has similar electrical properties you will be fine. I used the 7AF and 7N7, which are electrically very similar = 7AF7, to identical = 7N7, to replace 6SN7GTs in a Space Tech Lab amp .... worked great. I also used the 6CG7 which has been termed a 9 pin 6SN7GT in the Space Tech and again the results were very good sonically with no operational issues. I actually did try some 6CG7 pinout tubes in the 6CG7 adapter that were electrically different like the 6BK7A ands 6BZ7 .... the results were not good sonically at all .... which is the whole point of tuberolling so I went no further. Therefore, I cant answer if the tube was going to have operational issues.

I rolled in some to remain nameless pentodes ( until I cherry pick them
icon10.gif
) in my Sound Quest SQ-84 and the subs I used stomp the nos 6V6GTs I was using. I figured the substitution would work but I didnt expect the subs to be plain awesome. I have had the tubes running for up to half a day with no red plates, no distortion, no gain issues etc...
beerchug.gif


This begs the question .... are some tubes just superior sounding so that even in supposedly suboptimal circuits they sound better than the tubes the amp was specifically designed for? I cant answer that definitively but the answer seems to be .... sometimes yes.
 
Nov 13, 2008 at 1:10 AM Post #7 of 84

nikongod

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Quote:

Originally Posted by Skylab /img/forum/go_quote.gif
HOWEVER, if you want a great alternative to the 6SN7 you can use with adapters in any amp, try getting some 6F8G's (VT99's).


On the one hand, why did you have to go and spend all of my pocket lint? I was all set and ready to build another cmoy and now BANG!

On the other hand, thank you very much. The bl63 looks cool. lots of heater current, but thats OK
smily_headphones1.gif
 
Nov 13, 2008 at 1:23 AM Post #8 of 84

Skylab

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Quote:

Originally Posted by nikongod /img/forum/go_quote.gif
On the one hand, why did you have to go and spend all of my pocket lint? I was all set and ready to build another cmoy and now BANG!



Ha! My pleasure to spend your money
biggrin.gif


Seriously, the 6F8G is a VERY good sounding tube. I recommend it highly. I have RCA's, National Unions, Raytheons, Tung Sols, and Sylvanias, and they all sound very, very good.
 
Nov 13, 2008 at 4:34 AM Post #9 of 84

sacd lover

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Quote:

Originally Posted by Skylab /img/forum/go_quote.gif
Ha! My pleasure to spend your money
biggrin.gif


Seriously, the 6F8G is a VERY good sounding tube. I recommend it highly. I have RCA's, National Unions, Raytheons, Tung Sols, and Sylvanias, and they all sound very, very good.



I have a couple adapters on the way and I will be tube shopping tomorrow!!
biggrin.gif
 
Nov 13, 2008 at 1:19 PM Post #10 of 84

Skylab

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NICE! Nothing better than tube shopping
biggrin.gif
 
Nov 13, 2008 at 8:26 PM Post #11 of 84

sacd lover

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Quote:

Originally Posted by Skylab /img/forum/go_quote.gif
NICE! Nothing better than tube shopping
biggrin.gif



I bought 8-9 6F8Gs to try. I think got one NU, one KR, one RCA, three Raytheon and three TS.
 
Nov 13, 2008 at 11:11 PM Post #12 of 84

mourip

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Great thread and thanks for the tips.

I also bought one of those adaptors and got a Kenrad tube.

Yesterday I sold some 6GM8s had the money in PayPal for about 5 minutes and then turned around and bought an old pair of Stax SR-5's from another Headfir just to taste the STAX world a bit.

I love this place!
 
Nov 13, 2008 at 11:13 PM Post #13 of 84

mourip

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Quote:

Originally Posted by sacd lover /img/forum/go_quote.gif
I bought 8-9 6F8Gs to try. I think got one NU, one KR, one RCA, three Raytheon and three TS.


Where are you shopping?

:)
 
Nov 14, 2008 at 12:48 AM Post #15 of 84

Skylab

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Quote:

Originally Posted by sacd lover /img/forum/go_quote.gif
I bought 8-9 6F8Gs to try. I think got one NU, one KR, one RCA, three Raytheon and three TS.


Wow - that's a nice little collection!

Definitely start with the Tung Sols
smily_headphones1.gif
 

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