most popular brand replacement 12AX7, 12AT7, 6V6, 6L6, KT66, KT88

[Chuck H]

Most probably, yes. But I have seen (and cured) speaker EM feedback issues as well.

Yes. I was jumping the issue because microphony has been my primary frustration with new tanks. I've had to deal with speaker induced EM too on one occasion. Grounding the speaker frame cured it immediately.

[mikepukmel]

That's what I thought was a bit odd about this (why I thought, with my lack of experience with building/diagnosing problems): I had the guitar unplugged, turned the amp on after some fixin, looking for smoke and sparks. Didn't get that, so I started turning the knobs up and down. With nothing plugged in, if I fiddle with the vol and reverb controls, i can get it to ring, without having played anything. This was with the tank sitting in its bag, on top of the combo cab, and the chassis on the stand on my desktop. I have the little foam thing that came with the tank someplace, will try to carefully put that in without breaking anything.

I was able to get the reverb knob to 10 (eek, horrible long cavernous reverb) with the tank on the desktop behind the chassis, and the cab on the floor. So seems like this one could be either, since if its EM, tank is pretty far from the speaker at this point.

Geez, these things are tempermental. I read a post someplace on one of the music blogs by a guy, said "I will NEVER build another amp with reverb". Heh, not quite there yet, but been a learner.

[Leo_Gnardo]

I was able to get the reverb knob to 10 (eek, horrible long cavernous reverb)

So, can we agree there's never any point to dialling the reverb all the way up to 10? That's right, I thought so...

One thing I do that's turned out to be popular with the amp owners/users, pad the reverb control. Stick say a 270K, maybe even 470K in series with the reverb pot. That should open up the control zone on the pot so it's not "too loud, too fast." Also, dialling it up to 10 won't be so far into the obnoxious zone. One potential complaint left: "golly, it sounds kinda dark..." Then you can bypass that pad resistor with a little disc cap, you'll have to season to taste on this one. Say somewhere between 180 and 470 pF.

[mikepukmel]

So, can we agree there's never any point to dialling the reverb all the way up to 10? That's right, I thought so...

One thing I do that's turned out to be popular with the amp owners/users, pad the reverb control. Stick say a 270K, maybe even 470K in series with the reverb pot. That should open up the control zone on the pot so it's not "too loud, too fast." Also, dialling it up to 10 won't be so far into the obnoxious zone. One potential complaint left: "golly, it sounds kinda dark..." Then you can bypass that pad resistor with a little disc cap, you'll have to season to taste on this one. Say somewhere between 180 and 470 pF.

Way cool, thanks Leo ... looking throguh my parts boxes to see what I have to try that out! -- have all the parts.
Yeah, 10 on the reverb is just wrong. Even that beach boys surf sound didn't use 10 on the reverb.

[Justin Thomas]

Yeah, 10 on the reverb is just wrong. Even that beach boys surf sound didn't use 10 on the reverb.

Yeah, but kick your amp for a special effect!

Jusrin

[Leo_Gnardo]

Way cool, thanks Leo ... looking throguh my parts boxes to see what I have to try that out! -- have all the parts.
Yeah, 10 on the reverb is just wrong. Even that beach boys surf sound didn't use 10 on the reverb.

Since you'll be experimenting with resistor values at the reverb/dry mixer, you can also reduce the reverb level by upping the value of the reverb leg of that mixer. Two ways to go about it, you can do either or both.

As far as reverb on 10, I can think of a track on some early Jefferson Airplane album, just Jorma alone, sounding like he's lost way back in the subway tunnel. Definitely not something you would do more than once in a lifetime. And who knows, that reverb may actually be the RCA studio's chamber, not a Fender spring reverb in the amp.

Hmm, it was Embryonic Journey, on Surrealistic Pillow. Acoustic guitar, so probably the chamber echo. Good track anyway you slice it, it has a way of settling the mind. Treat yourselves dear readers:

[mikepukmel]

Yeah, but kick your amp for a special effect!

Jusrin

Oh, man, doesn't even need a kick, a little bump and that thing lets out that star trek enterprise phaser sound.

[mikepukmel]

Since you'll be experimenting with resistor values at the reverb/dry mixer, you can also reduce the reverb level by upping the value of the reverb leg of that mixer. Two ways to go about it, you can do either or both.

As far as reverb on 10, I can think of a track on some early Jefferson Airplane album, just Jorma alone, sounding like he's lost way back in the subway tunnel. Definitely not something you would do more than once in a lifetime. And who knows, that reverb may actually be the RCA studio's chamber, not a Fender spring reverb in the amp.

Hmm, it was Embryonic Journey, on Surrealistic Pillow. Acoustic guitar, so probably the chamber echo. Good track anyway you slice it, it has a way of settling the mind. Treat yourselves dear readers:

Thanks for the link, Leo, forgot about this one. Wow, what a great sound. Will be experimenting with the various reverb parts you suggested, hopefully early next week, just waiting on parts.