Frankie99 wrote: Tue Apr 15, 2025 10:43 pm TY for the reply, I know lots of folks do it that way, yours are so clean I was curious.

I've been spraying enclosures with a rattle can from the auto parts store to see what that looks like. I like the old ford red with some cream or gold knobs....

Dr Tony Balls wrote: Sat Mar 01, 2025 4:55 pm Balls BF-2R! AB165 Bassman-based circuit with added reverb and bias wiggle tremolo. The back end is two ECL84 tubes, cathode-biased for ~2 watts. Gorgeous looking and sounding Jupiter 8SC 8" speaker. 17" x 13.5" x 7.75". Intended to be a house amp that sounds like bigger push-pull amp.

VaticanShotglass wrote: Thu Apr 17, 2025 4:49 pm I love this. Speaks to my tastes. The aesthetics are fantastic. Then there's the reverb and tremolo--was that a pain working into the design?

I've always wanted a bassman of that era, but I'd never have cause for the full blown deal. Thought of something closer to 20ish watts in a 1x12 combo, but that would still probably be too much. I'm fairly resigned to the fact that I'm likely to only play in small spaces these days.

I still love my 68 champ, but have wondered if there was some variety of 12" speaker set up that sounded nice in a living room across the full volume sweep (that is sounded nice even at the low settings). I have webber alnico sig8 in the champ now and it sounds nice, but I've wondered if there are more flexible options out there to just sound bigger without necessarily sounding louder.

Anyway, nice job. How do you like the output stage with those tubes and all?

llllllllllllllllllll wrote: Fri Apr 18, 2025 5:28 pm Which would be a bigger pain - installing reverb into a combo amp build like that or instead making a second 3 knob reverb unit to match with your new (reverb-less) Balls amp?

Dr Tony Balls wrote: Fri Apr 18, 2025 9:58 am

VaticanShotglass wrote: Thu Apr 17, 2025 4:49 pm I love this. Speaks to my tastes. The aesthetics are fantastic. Then there's the reverb and tremolo--was that a pain working into the design?

I've always wanted a bassman of that era, but I'd never have cause for the full blown deal. Thought of something closer to 20ish watts in a 1x12 combo, but that would still probably be too much. I'm fairly resigned to the fact that I'm likely to only play in small spaces these days.

I still love my 68 champ, but have wondered if there was some variety of 12" speaker set up that sounded nice in a living room across the full volume sweep (that is sounded nice even at the low settings). I have webber alnico sig8 in the champ now and it sounds nice, but I've wondered if there are more flexible options out there to just sound bigger without necessarily sounding louder.

Anyway, nice job. How do you like the output stage with those tubes and all?

The reverb and trem werent a huge pain, but definitely needed some experimenting. This was for a friend/client who was very unerstanding of the experimental nature and that some things will need tweaking and time to get right. The stock reverb was very strong....which a plus for some surf types but he wanted to tone it down quite a bit so we did that. And for the trem the original idea was to have a bias wiggle on the preamp like a Vibro champ so it could be before the reverb, but that turned out to be a noisy mess so we resorted to something more princeton reverb like.

You could always try plugging your champ into a 12 and see how it sounds?

I definitely like those tubes BUT i may be shying away from using the triodes in them for the phase inverter. Ive heard they're akin to the gain of a 12AT7 triode, so figured they'd work great for a LTPI. We found this amp was a bit grindy all around and tried a bunch of different tricks to tame it, and what ultimately helped was using a 12AT7 instead of a 12AX7 in the position before it. Basically driving the PI less. BUT the thing is I have another earlier build here that doesnt use the ECL84 triodes for the LTPI. It just ignores them and uses a proper 12AT7. And THAT amp sound great and clean all around, truly like a mini version of a big amp which was the whole point. Anyway...i've been meaning to ask some heavy heads on the EL34 forums for their thoughts on this, just havent gotten around to it yet. If I were to do it over I might change the phase inverter to a proper 12A*7.

• super interesting design stuff you done there!

• When emulating a design like the bassman in this case, how much is it just voicing the preamp after the target amp and then just working out a power amp that suits the desired usage? Or is it a lot more complicated, like you using these less common tubes in a configuration that also emulates the output stage?

• I imagine its more than with those Silverface Princeton Reverb reissues Fender did several years back where they said they voiced one channel to sound more like a Bassman (I never tried one) or when some dude revoices a channel on his Twin Reverb to sound more like a Marshall?

• Or is it that by the time the power amp design comes into play, the amp is now loud enough that the intended use would rule out the bigger emulated amp making the difference irrelevant?

• I'd love to try out a bunch of speakers set ups with my champ, but I'd have to plan to drive a few hours to civilization.

• I have tried a 2x10 cab and a 1x15 cab with the Champ. The 2x10 was excessively barky and percussive, and the 1x15 was an oddball univox bass cab from the 60s that always sounded like I was listening through a conch shell. They were both closed back cabs and I think I prefer the open back sound of most fender combos.

• I'm pretty ignorant of speaker info, but at some point gained the impression that I preferred "American voiced" designs. IDK anymore.

• I don't think I've ever really gotten along with 10" speakers either.

• I'd like to experiment more, but I'm only ever around used Peaveys out here.

VaticanShotglass wrote: Sun Apr 20, 2025 7:35 pm

• When emulating a design like the bassman in this case, how much is it just voicing the preamp after the target amp and then just working out a power amp that suits the desired usage? Or is it a lot more complicated, like you using these less common tubes in a configuration that also emulates the output stage?