2. tech-talk
  3. 194998-198816

6SN7 tubes and variants question.

I was reading on something called Head Fi Focal, never heard of it before. I was just trying to find info on the 6SN7 variants. It said that GT versions are different than GTA and GTB versions and that you could cause damage to gear that was designed for the later versions, GTA/GTB types.

I use a Cary SLP 98P F1, which came with all EH 6SN7 tubes, no other nomenclature. Being modern, I can only assume that they are basically the same as GTA/GTB of the older tubes. I am currently using Sylvania GTB's and Raytheon GTB's. I have several others to try, including VT231's, GT's and GTA's. Is there any harm in using the older GT's or others from the 40's? It seems to me that these are favorites of many. I'd never read this before, just wondering what anyone here might think.

The claim was that the output of the GT version is 2.5 and the output of the GTA/B's is 5 and that damage could occur if you use the GT's in something designed for the later versions. I had never heard this before and it looks to me as though people interchange them all the time.  Thanks for any advice. 

Bill

billpete
tomcy6's avatar
tomcy6
2,636 posts
 

@billpete There used to be a tube dealer who wrote on his website that neither he nor anyone else could tell you how a tube will sound in your system.  Experimenting with what you have may be a better way to getting good sound than shopping for expensive tubes.  Enjoy!!

billpete OP
262 posts
 

@tomcy6 

I would agree with them. Every system is different. Certain components may work better with a certain tube or cable but an overall system is usually unique unto itself. The more I read that a certain tube is favored by many, it gets my attention and I will often try that tube. Expensive tubes are most often expensive because the market drove the price up. Supply and demand simplicity. How some can be worth thousands for a pair is hard for me to imagine. I would hope they sound very good. I will dabble a bit into the hundreds per pair but not likely to ever hear or own the ones that are in the thousands, just can't justify it. Especially when I am already enjoying tubes that I find for $10 to $50 or so each. OK, enough words just to say that I agree. Thanks.

billpete OP
262 posts
 

@immatthewj 

More tube rolling. Moved the National Union Black Glass GT's to the buffer position and put a pair of RCA  Smoke Glass GT's in the line/gain position. Maybe the best combination yet...........maybe. First time I've had 4 GT's in place. Was hoping to have the RCA VT 231's in but one tested with a short so had to look for and buy another. Still waiting for other VT's to be delivered, Raytheons and Sylvanias.

I have been testing everything with CD listening as it has been more reliable for me, having some battles with my vinyl rigs. I think I finally have most of the bugs worked out. Was using some custom made RCA's and ever since putting them in, I've been chasing my tail, trying to figure out what was wrong. I've changed tubes, numerous times, changed cartridges, turntables, everything except the damn cables. Cables and dedicated circuits in the works for next upgrades. 

I took the old Cary PH301 out of the system, thinking it may be the problem. It is getting quite old but to look inside, everything looks like new.........so who knows. Anyway,  using the SLP98 phono section now and was very pleased. First time I'd tried it with this tube combination and with listening to only one side of an LP, I was very pleased. Using Sylvania Gold Brand Gold pin 6189's and Sylvania Gold Brand Gold pin 5751's, which was always one of my favorite combinations in the old Cary. Probably had everything sounding the best that I've heard since owning the 98. Next thing to try is putting the PH301 back in as it should be even better than the 98 phono stage. Probably not by much but who knows. Will post as I make further improvements.

More to discover