valve experts - 6sn7 suggestions?

I just picked up a pair of VAC PA160 mkII monoblocks. They utilize 6sn7's in the input and driver stages. I have a quad of what appear to be NOS GE's. I was wondering if anyone has experience with the GE's. Also, what 6sn7's (or variants thereof) are you running? Thanks for your comments. Erik
I have a VAC Renaissance 30-30 MkIII. I use matched pairs of Sylvania NOS 6SN7-VT231 and Sylvania 6SN7WG brown base. Both lovely but hard to come by. Don't know anything about your GE. Good luck. VAC makes wonderful gear.
I also have a VAC 30/30 Mk V with the Signature upgrade, and have found the Sylvania's to be a very good choice. The VAC amps run the input tubes and driver tubes at very high plate voltage (over 400 volts) and you should be using a Sylvania GTB 6sn7 which are rated at 450 volts to be on the safe side, especially in the driver tube positions, which are run a bit hotter than the input tubes. The best sounding though is the VT231 which is not a GTB tube (it is rated at around 300 volts) It is common for some to run the VT-231's at these higer levels, but I had to go through a lot of 231's before finding a pair that were able to operate properly at these levels. The next best sounding tube is the late 40's early 50's GTB's. The input 6sn7's have the most dramatic sonic signature, where the driver tubes are not quite as obvious. The Sylvanias will have much better dynamics and bass impact compared to other NOS tubes I have tried. The original VAC tubes however, sounded better than all of the NOS I tried except for the Sylvanias. Kevin and the crew at VAC did a wonderful job of balancing the sound of the amps with their original stock tubes. The Sylvanias may be a bit more forward for some tastes in the mids., but that of course can be very system dependant. Hope this helps!
VT231 is simply the military designation for 6SN7s. one and the same tube, ultimately. GTA, GTB, WGTA are all rated at 450v, I believe. Personally, I find the GTBs the worst of the lot, much preferred IMHO are the earliest ones: 6SN7w, 6SN7 GT, -WGT, and lastly GTA. About the only good GTBs are Tung Sol and perhaps a few select RCAs. There's many better sylvanias certainly than the later GTB stuff. (See above). GE isn't generally regarded as one of the choice NOS tubes to have, though certainly it's probably the equal of the chinese or Russian modern ones. Ones to seek out, IMHO: Ken Rad, Sylvania, Tung Sol, National Union, the earlier the better. Some of the 1945-52 Sylvania Tall-boys (bottom getter, tall envelope) and CBS/Hytron tubes are basically the same tube as the vaunted Sylv. vt-231, just w/o the military marking. Fortunately, there are a lot of good NOS tube choices in the 6SN7 family, and a fair amount of stock out there trading hands. have fun,
Thanks for all the input. I can't wait to start experimenting with all the possible combinations. The PA160 mkII's have so many variables. Tweaker city, baby. Erik
A real learning experience about the 6sn7's will start by paying a visit to Andy at V.T.S. (Vintage Tube Services)
He has a nice web page and is the authority when it comes to tubes of all sorts. He will soon be writing a book on tubes, and it should be one of the best around. He will straighten out any confusion about the voltage ratings and what you might need. I tried numerous Ken-Rads, Tung-Sols and Sylvanias from him, and it was an enlightening experience.
He has a great return policy, and will give you plenty of time to try out various ones. The Sylvanias have much lower
microphonics than the Ken-Rads and Tung-Sols, and are less "colored sounding" with the VAC amps. Happy tweaking!
Bigshutterbug (great handle),
Thanks for the lead. A valve return policy? Amazing. I have a buddy who has the same VAC's that I do. We are both benefiting from this thread. Again, thanks everyone.