16SL7+6SN7 Aikido

[regal]

I know the 6SN7 is well thought of.

What about the 6SL7 tube? Unfortunately I need the gain, is this the best high mu tube out there?

[offhand35]

I just recently completed a guitar amp using a 6SL7 or 6SN7 as preamp and PI to a 6SJ7 to 2 6V6GT's in pp. for approx 14 watts output. The 6SL7 was easily overdriven, and clipped so badly that output was stunted past 12:00 on the vol.

When I used the 6SN7, the amp worked great, though I suspect the actual output is probably less than the hoped for 14W, being a lower mu tube.

I have 2 different used 6SL7's, one a GTb, both behaved in a similar manner. This actually may all have been influenced by use of the 6SJ7.

An amp using a 6SL7 to a 6SN7 may be a better combination......

The 6SL7 is often mentioned as equivalent to a 12AX7. It actually may be a little more easily overdriven......

[vitalstates]

The 6SL7 is often mentioned as equivalent to a 12AX7. It actually may be a little more easily overdriven......

equivalent???

6sl7 has a mu of 70
12ax7 has a mu of 100

mmmmmm?

Ed

[Miles Prower]

Originally posted by regal
I know the 6SN7 is well thought of.

What about the 6SL7 tube? Unfortunately I need the gain, is this the best high mu tube out there?

Pretty much so, yes. I used the 6SL7 to make an LTP phase splitter for one project. Works just great, and I don't know of very many other high-u triodes with the same linearity. The 6SL7 comes from a time when amps didn't include ess-loads of gNFB, and so more attention to linearity was paid. It can make a good amount of gain, but typically draws very low currents and doesn't make such a swell driver for finals. Definitely needs cathode follower help there.

6SF5s are also pretty good in the gain dept, but that one is a metal, octal singleton, not a dual.

"The 6SL7 is often mentioned as equivalent to a 12AX7. It actually may be a little more easily overdriven......"

No similarity other than that both types have large r(p) (static and dynamic). Otherwise, the 6SL7 is an octal; the 12AX7 a nine-pin mini type. The 12AX7 has a higher u-factor (100 v. 70) higher r(p), and seems to be somewhat less linear. Plate dissipation is also dofferent: 1000mW (6SL7) v. 1200mW (12AX7). Other than that, dunnow since I haven't used a 12AX7 yet.

[ray_moth]

I use a 6SL7 LTP splitter, feeding 6SN7 differential amp, driving EL34s in triode mode. I have no complaints and the 6SL7 doesn't overload. It's being driven only by a line-level signal from a volume control, so I wouldn't expect it to. I don't need no steenkin preamp!