Stefan Wood
Active Member
I have a magi preamp that uses sylvanias 6sl7 tubes. I want to tube roll and realized I picked up a pair of 6sn7 tubes. Are they compatible or do they have different specs and it would make the sound not so good?
6sl7 and 6sn7
- Thread starter Stefan Wood
- Start date
cademan
Lunatic Member
They have different specs. The 6SL7 is like a 12AX7. The 6SN7 is like a 12AU7.
6SL7 = 70 (amplification factor)
6SN7 = 20 (amplification factor)
Stick with the 6SL7!
http://www.mif.pg.gda.pl/homepages/frank/sheets/049/6/6SL7GT.pdf
http://www.mif.pg.gda.pl/homepages/frank/sheets/137/6/6SN7GT.pdf
6SL7 = 70 (amplification factor)
6SN7 = 20 (amplification factor)
Stick with the 6SL7!
http://www.mif.pg.gda.pl/homepages/frank/sheets/049/6/6SL7GT.pdf
http://www.mif.pg.gda.pl/homepages/frank/sheets/137/6/6SN7GT.pdf
Last edited:
Tom Bombadil
AK Member
Both will frequently "work" in the same circuits, but they are quite different tubes and generally are not swapable in terms of achieving high quality sound. I have an amp which was designed to use 6SN7 in the driver stage. The amp designer says that one could also use 6SL7, so I tried them. The resultant sound was much shriller to my ears and I took them out immediately.
For one thing the 6SL7 has a much higher gain.
For one thing the 6SL7 has a much higher gain.
Stefan Wood
Active Member
Got it. Any recommendations for 6sl7 tubes? I have sylvanias but open to other suggestions for rolling.
RUmad
Super Member
I had JAN Philips WGT’s in my amp for over 15 years that sounded great. Still going strong actually, and they see LOTS of time. Recently bought a set of JAN Sylvania WGT’s from @byoungman1 that sound absolutely amazing, so I pulled the Philips and am saving them as backups.
Find NOS tubes from 1950s. Some are better than modern copies.
Stefan Wood
Active Member
6sl7 not 6n7 to be clear is what I am looking for.
Stefan Wood
Active Member
I've ordered a pair of Sylvania 6sl7WGTs and Sylvania VT-229s. Will try and hear what differences they may bring.
Those are cheap and plentiful, and work well. I bought a load of them direct from Russia off eBay and use them as a general purpose 6SL7 replscement.
For old stock I suggest RCA, GE, or Sylvania. Japanese tubes like TEN can sound good too.
Stefan Wood
Active Member
I have not heard good things about RCA, except for the red base ones. What Japanese or Russian tubes should I look for?
RCA engineers invented the 6SN7 and 6SL7, along with the 12AX7, 12AU7, 6L6, and many other tubes we commonly use. I regard their 40s and 50s production as the gold standard of American tubes, especially from the 30s, 40s, and 50s era.
Have used RCA 6SL7GT for thousands of hours, enjoying good sound, low noise, and little degradation of tube characteristics. What bad things have you heard? I know some of their later color TV tubes like the 6GH8 didn't last well, but the older designs sure did. I consider the foreign tubes to be knock offs of the genuine RCA 6SL7.. the Russian ones you can find easy enough. Japanese tubes are harder to find, the brand I referenced above is TEN - I just happened to find some of them in old gear, and enjoy them. They were sold as a discount alternative to the domestic tube brands back in the 60s.
One thing about RCA, is they stopped making consumer tubes in 1976. Sylvania stopped in 1988, and GE in 1991.. because of this actual new old stock RCA is harder to find. Something you have to be wary of with old stock tubes, is the brand name printed on the tube is often not who made it. All the big names often relabeled each others tubes, so it is common to find a GE tube with an RCA or Sylvania brand, or vise versa.
Have used RCA 6SL7GT for thousands of hours, enjoying good sound, low noise, and little degradation of tube characteristics. What bad things have you heard? I know some of their later color TV tubes like the 6GH8 didn't last well, but the older designs sure did. I consider the foreign tubes to be knock offs of the genuine RCA 6SL7.. the Russian ones you can find easy enough. Japanese tubes are harder to find, the brand I referenced above is TEN - I just happened to find some of them in old gear, and enjoy them. They were sold as a discount alternative to the domestic tube brands back in the 60s.
One thing about RCA, is they stopped making consumer tubes in 1976. Sylvania stopped in 1988, and GE in 1991.. because of this actual new old stock RCA is harder to find. Something you have to be wary of with old stock tubes, is the brand name printed on the tube is often not who made it. All the big names often relabeled each others tubes, so it is common to find a GE tube with an RCA or Sylvania brand, or vise versa.
Dandy
Addicted Member
6H9C. Mine are from the early 70s. I forget which maker.
Stefan Wood
Active Member
What I had heard from people who owned those tubes was that they colored the sound compared to the 5691 red bases or the Sylvanias or certain Tung Sols.
There was a post in this forum I believe from someone who owned a 300B amp and for his preamp he installed JAN Philips 6sl7s and stated that they did not detract from the clarity of the amp. I have a type 45 amp and am looking for something similar.
This kind of analysis is going to depend heavily on the circuit of your specific amp, and everything about your system including how it is set up, the condition of the specific tubes, what equipment it is used with, etc.
It is one of those cases where you need to just buy some tubes and draw your own conclusions, since the question you are asking is extremely subjective.
I can only answer questions about objective things like tube longevity, noise characteristics, distortion, etc.
Stefan Wood
Active Member
Yes that is what I figured.
Here is a simple reminder: random subjective opinions are not very useful in general. If person A says tube B didn't sound good, it offers very little useful information. What was the function of the tube in the circuit (for instance someone mentioned a 6SN7 as a cathode follower in a post above; that's a very different use than a voltage amplifier)? What was the operating point of the tube? One can easily change the sound of a tube in a circuit from clean and precise to vague and warm simply by changing the operating point. It can be fun to inform others about your successful audio endeavors, but that doesn't always translate into information other users can duplicate.
Stefan Wood
Active Member
True. That is why I am rolling; I just wanted to narrow my buying options.
