Other Cascaded preamps NOT 12ax7s

[robertkoa]

At this point (I'm a player not a tech ) we have heard cascaded 12ax7s in all kinds of circuits. Is it possible that OTHER preamp tubes (ok,the first stage or 2 can still be a 12ax7 for low noise maybe) may clip or distort more musically with a wider sweet spot, require less filtering etc.? What do you guys think, anybody cascade 6 sl7 or other tubes with good results? Is this a fertile area for experimentation-for example do pentode preamp tubes clip more gradually and sound like output tube distortion ? I recall a builder Victoria Amps who used an ef86 and Tonequest reported the amp was great and unique, but discontinued by the builder 'cause of microphonic problems with those tubes. But the 6sl7 and 6sn7 tubes may give us a whole new palette of tones if they are exploited -what do you tube wizards think?

[Cygnus X1]

I can't answer, but I'm very interested to see what comes up here.
I've been thinking along the same path-especially concerning 6SN7's.

I have not taken the time to chart it out.

[Andy Le Blanc]

Now you need to be specific about "cascaded". The are many variations of mu followers
srpp, and cascoded stages. But whats good for hi-fi doesn't always make
a good guitar tone.

Pentodes are fun, I put a 6sj7 in a bass pre for giggles, but you know, they
really do have a good tone. I'd like a current production tube that was well
rated for audio.

[Wayne]

It's a shame there aren't more tubes in current production. I think I read somewhere that for every tube type produced today there are about 300 that are not. NOS, especially for less common types, will be around for a while, but eventually we'll be entirely at the mercy of what's being built today.

I know some of the guys here have done some neat things with unusual old tubes. It'll be a shame if supplies of these dry up or become too expensive to buy.

There seem to be enough preamp triodes in the 12A_7 family to accomplish different objectives, although having more choices would probably lead to new and interesting tones. I wish there were more preamp pentodes in current production, as well as output pentodes one "size" smaller than 6v6 or EL84.

W

[dartanion]

6SL7 and 6SN7s are both very cool sounding tubes and I would recommend trying them out. Although, these are known to be very prone to microphonics, so there aren't many builders using them. I did a plexi style preamp years ago with 6SN7s and it was super cool. Fat and warm, with a smokey overdriven tone. Had problems finding non microphonic tubes, so I tore it apart and built something else. Took a lot of futzing to keep the head isolated from vibrations, so I just gave up on it.

With that said, I am doing a couple of amps now that will be using 6SN7/6SL7 for preamp and PI. Sort of Wreck like, but different.

[martin manning]

Another data point, not too far off the beaten path, is the Electro-Harmonix "English Muff'n" tube pedal, which uses a pair of 12AY7's wired up pretty much like a Marshall 2204, with three gain stages (all three with bypassed cathode R's, though), and a cathode follower driving a Fender-Marshall-type tone stack. I suppose that choice (Y vs. X) was made to keep the overall gain down, seeing as how this thing will likely be fed into another preamp. Not surprisingly, it has great tube-amp tone and touch sensitivity.

MPM

[dartanion]

Well, if you look at most 12AX7 based preamps that are cascaded, they dump gain between stages with voltage dividers. Too much gain there already, so using lower gain tubes can allow you to remove or pair back the voltage dividers, and in the case of the English Muffin, allow for stability in a small package.

[funkmeblue]

I built an "express" with 6sl7's