The Reference 6SN7 Thread

[ericr]

Ok, I'll bite,

Can you guys least a few of the most underrated 6SN7s out there - so an ambitious, but noob audiophile can experiment with NOS tubes on the cheap? (I hope).

Thank you!

6SN7 x 4 will not = cheap, unfortunately.

In my experience the 6SN7 market is pretty well sorted out and for the most part you get what you pay for. Sure, if you watch ebay closely over several months you'll likely snag deals on 2 or 3 singles of different brands, but good luck for closely matched quads. You will likely be buying from a professional seller and paying the going rate.

All that aside:
-Sylvania 6SN7GT with T plates, short bottles and chrome flashing 1/2 to 3/4 the way down (late.1940s thru early 1950s).
-Hytron 6SN7GT T.plates with 2 holes/rivets per plate - a bit light on bass in my amp but otherwise very nice (late 1940s thru 1952ish - my later one is CBS labeled with 3 holes isn't as good sounding).
-The National Union black glass is said to be quite good and can be very reasonably priced (huge price variations on this one for some reason).

Good luck finding quads!

Or, don't mess around and go for the good stuff: Sylvania 6SN7W (black base is the best value, but must have only 2 holes per plate), or the Tung-Sol black round plate (for a warmer/thicker/richer sound).

 

[RoundRound]

Plus, while these pairs each have 2 tubes that are reasonably matched, it doesn't automatically make them a matched quad. A1 has a plate at 6.5 while B2 has a plate at 8.0. I'm not familiar with your amp but that seems to be a bit wider spread than many "matched sets" I've seen for sale. It would probably be best to check with experienced owners of your amp before buying.

Assuming the questions Skylar raises are answered favorably, for 1960s Sylvania 6SN7s (vs 1940 or 50) the price is OK though not any sort of killer deal.

 
Thank you,
I want to use this quad in a Schiit Freya (once they come out!) pre-amp. 
Here's what Schiit has to say abouty the issue of matched tubes:
 
With respect to tubes, yes, you'll want matched tubes at least for the input pair. The input pair does voltage gain, so it's the most critical. The input pair is on the right-hand side of the quad. The output pair is on the left-hand side. It's a follower, so it's less critical. 

 

We're also doing some degeneration of the input, so matching will be less critical, but you're still going to want to have reasonable matching.

No biasing is necessary, since the input is run off a current source, which sets the operating point of the whole system.
 
Does this help? I think the second pair is less critical?

 

[ericr]

Well, they do know their Schiit!

Based on that info I would be comfortable with the matching of those pairs for the Freya. Just put the closest matched pairs on the right side.

So the matching is OK, but what does a new 6SN7 read on the sellers tester?

 

[Csericks]

Can you help me I'm new to the 6sn7 world. I picked up a few tubes for a 2nd amp that I'll use at work. I suspect these are all rebrands and I'd like to know what I actually have. Can you help? Thanks!

 

[JohnBal]

  Can you help me I'm new to the 6sn7 world. I picked up a few tubes for a 2nd amp that I'll use at work. I suspect these are all rebrands and I'd like to know what I actually have. Can you help? Thanks!
 RCA?
 Sylvania?
 Sylvania?
 Sylvania?
 National Union?
 Sylvania?

 
 Those are my best guesses. But don't bet your life, I could be wrong.

 

[Csericks]

Thanks for your input! Any of them worth listening to?

 

[432789]

??? 

 

[RoundRound]

Hello People,
 
I bought a pair of matched Tang Sol VT-231's - please see picture:
 
 

 

 
I'm trying to figure out the date code, it's a bit blurred but reads SC 66 A - elsewhere its stamped BBB - not sure what this means.
Any advice would be welcome - thank you!

 

[hackstu]

Does anyone know of a genuine supplier of psvane/shuagang tube/valves on ebay??

 

[Oskari]

Hello People,
I'm trying to figure out the date code, it's a bit blurred but reads SC 66 A

I don't think that's a date code. That SC and A is a reference to US Army Signal Corps.

 

[RoundRound]

I don't think that's a date code. That SC and A is a reference to US Army Signal Corps.

Thanks mate, very helpful.
 
How can I figure the vintage of these tubes then?
 
Best,
Yarden

 

[Oskari]

How can I figure the vintage of these tubes then?

Since they have the VT-231 number, they should be quite old, roughly WW2 kind of old.

Do you have the boxes? Any additional info there?

 

[RoundRound]

Since they have the VT-231 number, they should be quite old, roughly WW2 kind of old.

Do you have the boxes? Any additional info there?

No,
Sadly no boxes. No worries, when the mythical Freya finally reaches British shores I'll be able to actually hear these tubes. 

 

[Jozurr]

  Hello People,
 
I bought a pair of matched Tang Sol VT-231's - please see picture:
 
 

 

 
I'm trying to figure out the date code, it's a bit blurred but reads SC 66 A - elsewhere its stamped BBB - not sure what this means.
Any advice would be welcome - thank you!

 
How much did these cost you? Are they NOS?

 

[RoundRound]

I paid about $160 delivered - I believe they measure like NOS