[zybar]

Right now I have the stock KT-88 and 6SN7 tubes in place as I wanted to spend the first 3-4 weeks just getting a handle on the amp before thinking about any tube changes.

Has anybody out there done any tube rolling?

What did you try and what did you hear?

Thanks,

George

[woodsyi]

Boy, it's been a while since I went though a lot of tubes on my 200.  Let me see if I can remember the details.  After much juggling I ended up with RCA read base 5692 for input and Sylvania chrome tops for drivers.  For the power tubes I used a Von Gaylord Starlet (which uses only 4 power tubes) to audition kt88 and 6550s.  I ended up with reissue Tung Sol 6550s on my 200s.  I actually like Kuhl tube JAN 6550s but could not afford 16 of them. SED winged 6550s are supposed to be good but I never tried.  Tung Sol 6550s are little more resolving than EH KT88s.  They could also be bright with "wrong" driver tubes. 

I only use the Bellas from 270 Hz and up.  So I can't tell you about bass response but I think you are in the same boat?  The RCA/Sylvania input/driver combination  gave the best vocals for me.  I also found that rolling the signal tubes made more differences than the power tubes.  People who were commenting on stock ASL gear have also commented that mixing the input and driver gave better result than using the same tubes all across.  Good luck and have fun.

P.S.  I have a box full of 6sn7s around if you want to try them. 

[zybar]

Boy, it's been a while since I went though a lot of tubes on my 200.  Let me see if I can remember the details.  After much juggling I ended up with RCA read base 5692 for input and Sylvania chrome tops for drivers.  For the power tubes I used a Von Gaylord Starlet (which uses only 4 power tubes) to audition kt88 and 6550s.  I ended up with reissue Tung Sol 6550s on my 200s.  I actually like Kuhl tube JAN 6550s but could not afford 16 of them. SED winged 6550s are supposed to be good but I never tried.  Tung Sol 6550s are little more resolving than EH KT88s.  They could also be bright with "wrong" driver tubes. 

I only use the Bellas from 270 Hz and up.  So I can't tell you about bass response but I think you are in the same boat?  The RCA/Sylvania input/driver combination  gave the best vocals for me.  I also found that rolling the signal tubes made more differences than the power tubes.  People who were commenting on stock ASL gear have also commented that mixing the input and driver gave better result than using the same tubes all across.  Good luck and have fun.

P.S.  I have a box full of 6sn7s around if you want to try them. 

I am using the Bella's full range on the 5A's and they sound wonderful in triode mode.

I believe my amps have Valve Art KT 88's (Bill jump in if I am wrong), not really sure on the 6SL7 and 6SN7's.

I'll PM you on the 6SN7's - thanks.

George

[toobluvr]

I have had several amps that use both 6sn7 and 6sl7, so I have been around the NOS block on these.  Be prepared to re-mortgage your house for the best.    Supply is dwindling with each passing day, so you will pay thru the nose for truly mint and unused.  I would usually just go with "used, test strong".

I have found the best to be WW2 vintage VT231.  I like Raytheon, Ken-Rad and Tungsol...especially the black glass ones.  They are rich, musical, clear, extended, balanced and punchy.  The Ken-Rad have particularly big bass. 

I find the RCA Red Bass 5692 (and all RCA I have heard in this family) to be fuzzy, veiled and indistinct.  Some peeps love them and they are pricey. 

Sylvania vt231 have a big following.  They are very precise, neutral and fast, and in the right system would probably be just the ticket.  But I find them to be a bit cool, analytical, insistent, and sometimes lean for my taste.

Dennis Boyle at Chimera Labs is a bit of a guru on these types.  He has put together some nice comments and reviews on different NOS.  I have owned many of the ones he comments on.  For the most part, my impressions are in line with what he presents here.  I believe this is a good starting point.

For 6sn7 / vt231:    http://home.att.net/~chimeraone/6sn7sound.html

For 6sl7 / vt229:     http://home.att.net/~chimeraone/6sl7sound.html

Search AA for tons of stuff on these types.  You can spend almost a lifetime researching and learning about these.  I know I did!   Have fun!

[Bill Baker]

I believe my amps have Valve Art KT 88's (Bill jump in if I am wrong), not really sure on the 6SL7 and 6SN7's.

 That's right George, the KT88's and 6SN7s are Valve Art with the 6SN7 being a Russian. I also have to agree with Woodsyi in that the input/driver tubes can make a bigger difference than going with expensive power tubes. My view on this is to find a decent power tube that you like and then you can start your search for the others. NIB NOS 12 series tubes can be very pricey. They are also subjective (as are tube choices in general) and this is why I don't get involved with recommendations. My cup of tea may not be yours.

 For power tubes, I do like the VA KT88 and EH KT88 but then go to the 6550. I am no really of a fan of the SED in the 100's as they are a bit too mushy in comparison. I will be doing a bit more tube rolling this summer for with the signal tubes. If I can find another new quad of JAN GE 6550's to match the set I have stashed in my closet, that what I will run for output tubes.

[zybar]

Thanks again to everybody for their comments.

I am going to try a pair of Tung-Sol 6SU7GTY from the 1950's that I am getting from Jim McShane next week.

Sometime in July I will be getting the Genalex Gold Lion KT-88 reissues from Jim McShane as well.  Jim has stated that these KT-88's sound wonderful and that he hasn't seen any quality issues.

George

[zybar]

Quick update...

I had some issues with playing around with the 6SL7's, so I have been trying different 6SN7's in the amps.

First I tried 1 pair RCA red base 5962 and 1 pair CBS Hytron brown Base 5962 - these were a little too soft and fuzzy.

Next I tried a pair of Sylvania GTA Chrome Tops (V5 socket) and a pair of GE GTB side getter (V7 socket) - this produced a little more detail and sparkle than  the stock tubes, but still wasn't really rocking my world.

Today I inserted a barely used pair of Sylvania 6SN7W Metal Base in the V7 sockets and HOLY COW BATMAN!!! 

It was like hitting the nitrous button and hanging on for dear life!

Tons of detail, texture, and slam!!

I will need to try the Sylvania 6SN7W Metal Base tubes in the V5 socket and see if it is better suited there. 

Either way, I think I have found one half of the 6SN7 equation for these amps.

George

[Bill Baker]

Thanks for the update George. It's always nice to hear what other's are experiencing with various tube combinations.

 Regard the 6SL7 tubes, has -------- sent you a different pair.

[toobluvr]

General guidelines to help voice in a certain direction:

If you need a more "accurate" sound with more speed and treble information (also a bit lean to my ears).....WWII vintage Sylvania VT231.

If you need more fullness, warmth, palpability and plain ol' musicality and beauty.....WWII vintage black glass tubes,  Ken-Rad VT231 and Tung-Sol VT231.  Raytheons also fall into this camp.

(PS:  not surprised by the RCA red Base 5692 performance....see my post above)

[zybar]

General guidelines to help voice in a certain direction:

If you need a more "accurate" sound with more speed and treble information (also a bit lean to my ears).....WWII vintage Sylvania VT231.

If you need more fullness, warmth, palpability and plain ol' musicality and beauty.....WWII vintage black glass tubes,  Ken-Rad VT231 and Tung-Sol VT231.  Raytheons also fall into this camp.

(PS:  not surprised by the RCA red Base 5692 performance....see my post above)

Since these amps take two 6SN7's each, I am thinking one from each camp might produce the best results.

John, your notes and links have proved spot on.   

George

[toobluvr]

General guidelines to help voice in a certain direction:

If you need a more "accurate" sound with more speed and treble information (also a bit lean to my ears).....WWII vintage Sylvania VT231.

If you need more fullness, warmth, palpability and plain ol' musicality and beauty.....WWII vintage black glass tubes,  Ken-Rad VT231 and Tung-Sol VT231.  Raytheons also fall into this camp.

(PS:  not surprised by the RCA red Base 5692 performance....see my post above)

Since these amps take two 6SN7's each, I am thinking one from each camp might produce the best results.

George

It just may.....
Impossible to know without trying.
I've had a few amps that used several pair of 6sn7.
You can go nuts (and broke!) with the almost countless combinations and permutations of 6sn7 family tubes.

[Bill Baker]

I've had a few amps that used several pair of 6sn7.
You can go nuts with the almost countless combinations and permutations of 6sn7 family tubes.

 This is where things can get crazy (and expensive) I have several amps that take anywhere from 2 - 6 pieces of 6SN7's per channel.