The Reference 6SN7 Thread

[FLTWS]

My 5998A's arrived. Adding them to my collection of Inky tubes including 6SN7 variants for drivers as well as other power tubes is in good shape with the addition of these 2 new ones.

 

[Paladin79]

My 5998A's arrived. Adding them to my collection of Inky tubes including 6SN7 variants for drivers as well as other power tubes is in good shape with the addition of these 2 new ones.

Now Ripper needs to get his tube and that will make four of us. Frank writes wonderful reviews so I am looking forward to his input.

 

[S0undJunk1e]

6SN7s such as RCA 5692, CBS/Hytron 5692 are there, are sometimes tough to locate, and are definitely $$$. Is your “anything” absolute or does it mean “anything reasonable?” If the latter, what is your budget per tube? Another route is to use 7N7 tubes with 7N7 (top) -> 6SN7 (bottom) adapters. The 7N7s can run up to $50 per tube as far as I have seen*. The adapters, up to $60 each depending on build.

* I have yet to come across Lansdale (Philco) 7N7s....

Let's say $225 per tube, assuming they aren't overpriced. I'd like to have the best (not necessarily best of the best, trying to get close). I did see the hytrons, but wasn't sure if they were worth that price. I'm also worried about tube life on the 5692 given how much they cost. using these in a feliks elise.

 

[jonathan c]

Let's say $225 per tube, assuming they aren't overpriced. I'd like to have the best (not necessarily best of the best, trying to get close). I did see the hytrons, but wasn't sure if they were worth that price. I'm also worried about tube life on the 5692 given how much they cost. using these in a feliks elise.

For consideration (and I have been a repeat customer of theirs for 5692 and other items):

 

[Paladin79]

For consideration (and I have been a repeat customer of theirs for 5692 and other items):

Let's say $225 per tube, assuming they aren't overpriced. I'd like to have the best (not necessarily best of the best, trying to get close). I did see the hytrons, but wasn't sure if they were worth that price. I'm also worried about tube life on the 5692 given how much they cost. using these in a feliks elise.

I want to say 5692's are 10,000 hour tubes, they should last longer than standard 6sn7's.

 

[Ripper2860]

I think the 5692's 10,000 hour life expectancy may be a questionable claim. Here's a snip from the 6SN7 reference thread...

Some words on tube reliability:

To ensure good tube reliability you should probably run a tube at 70% or less of its maximum plate dissipation.

Using the general audio application of 250 plate volts, a bias of 8 volts resulting in 9ma of current and plate dissipation of 2.25 Watts, we find:

5692 - runs 43 % over maximum rating – It isn’t a 10,000 hour tube when you run it this HOT!
6SN7GT - runs 64% of maximum – coasting and liking it
6SN7GTA/GTB - runs 45% of maximum – Hardly turned on, may outlast you.

 

[jonathan c]

I want to say 5692's are 10,000 hour tubes, they should last longer than standard 6sn7's.

Reading some of the commentary, history & literature about the CBS and RCA 5692s, I encountered quite a few references to reliability and ruggedness as necessary for military use.

 

[Paladin79]

I think the 5692's 10,000 hour life expectancy may be a questionable claim. Here's a snip from the 6SN7 reference thread...

One addendum to that - it seems RCA purposely under-rated the 5692 to be able to claim that it is a 10,000 hour tube in their marketing of the tube, so it is possible (but not certain) that it is quite safe at higher voltages...of course it won't be a 10,000 hour tube then (if it ever really was)...but you are quite right that people should check their plate voltage because not all 6SN7's are equal, and many manufacturers use very high voltages on the 6SN7 (GTA for example) in the belief that higher voltages make the tube more "exciting" sounding.
Since the 5692 was introduced in the late 40's, it can probably be used as a 6SN7GT as it can possibly handle that rating, but it is very unlikely to survive long used as a 6SN7GTA or GTB.

It depends on how it is run and in what equipment. Using it in a circuit designed for 6sn7's does make a difference.

 

[FLTWS]

For consideration (and I have been a repeat customer of theirs for 5692 and other items):

I paid $150.00 for Platinum Grade back in 4/2018 when I bought 1 of these as I was starting to tube (and wallet) roll with LYR3, found my e-mail receipt.
I started with Upscale back in May 2016 with 6922's when I bought my MJ2 (now a collectible ).
I've done a good number of purchases with Upscale and with Brent Jesse over the years.

 

[bcowen]

* I have yet to come across Lansdale (Philco) 7N7s....

Looks like some super-jerk bought them all.

But all is not lost....it's the internal configuration that separates these from the usual fare: tall bottle with getter flashing that covers 1/3rd to 1/2 of the inside of the bottle, opposed T-plates, and most importantly fully oval (racetrack) micas at the top and bottom. I have these with GE, Raytheon, Hytron, and Sylvania branding as well. Different logo, same tube.

 

[bcowen]

It depends on how it is run and in what equipment.

^^^^^^^^^^^^^^^^^^^^
This.

I don't think I've ever had a component using 6SN7's that put 250v to the plates. 90v - 150v is by far more normal.

To @S0undJunk1e : see if you can find out what plate voltage the Elise is running on the 6SN7's. If it's 150v (or less), the 5692's should be just fine and last quite a long time.

 

[Galapac]

Has anyone tried 7A4/7B4 tubes with adapter into a 6SN7 socket?
There are a lot of good, cheap tubes of this kind out there and was wondering if anyone tried these with any good results or is it an audiophile dead end?

 

[bcowen]

Has anyone tried 7A4/7B4 tubes with adapter into a 6SN7 socket?
There are a lot of good, cheap tubes of this kind out there and was wondering if anyone tried these with any good results or is it an audiophile dead end?

Yup. 7A4's anyway, which is basically 1/2 of a 7N7. Never tried 7B4's....5x the amplification factor of a 6SN7 or 7N7 might be an issue depending on the amp. Paired up with a Tung Sol 5998, these round plate Hytrons (no CBS, just Hytron) are my mostest favoritest as of 4/19/21 for rock and metal.

 

[Galapac]

Yup. 7A4's anyway, which is basically 1/2 of a 7N7. Never tried 7B4's....5x the amplification factor of a 6SN7 or 7N7 might be an issue depending on the amp. Paired up with a Tung Sol 5998, these round plate Hytrons (no CBS, just Hytron) are my mostest favoritest as of 4/19/21 for rock and metal.

Thanks Bill. So you really are a rocker, eh? I thought the Marilyn references were an inside joke but now I guess not. Well consider yourself in a great group for I am as well but will listen to anything with a great hook.

 

[S0undJunk1e]

I think the 5692's 10,000 hour life expectancy may be a questionable claim. Here's a snip from the 6SN7 reference thread...

This is exactly what I read, and why I was concerned about the 5692