Try another 470k resistor after C11, it's missing a voltage divider there (But has the grid leak so that's good) - but a 470k in series with the signal path is a significant drop, spec. high frequencies

The low-mids being weird/missing could be the 500k pots instead of the 1Meg on marshalls. you can try a 500k resistor in series with the pot pin because changing a whole pot can be a PITA sometimes depending on what you have to remove

So based on suggestions here and over in GroupDIY I'm planning to do the following:
First and foremost, take some measurements. I need to dig out my meter and scope and set up a space to work on this, but I'll go through and see if I can find anything wrong. Depending on the outcome of that, I think I'll then

-Recap (electrolytics) as preventative maintenance. Made in China~20 years ago doesn't instill confidence in quality control.
-Replace input jack with shorting switchcraft, and add the 68k grid stopper to V1A
-Remove C9 bypass cap on cold clipper
-Add 470K attenuator resistor between C11 and R15
-Replace R2 with 50K pot for variable bias, and add 1R cathode resistors to the power tubes for bias measurement.
-Generally inspect and touch-up solder joints as they don't look great at first glance.

and in response to some questions and suggestions here:

llllllllllllllllllll wrote: Tue Jul 25, 2023 6:45 pm Have you tried plugging in a different speaker?

Yes, connected the 2x eminence 10"s in my bandmaster reverb combo and it wasn't a noteworthy difference. For comparison, those sound great with the bandmaster.

numberthirty wrote: Tue Jul 25, 2023 9:59 pm So, about that Pignose...
Any chance you have a 12AY7 or a 12AU7 sitting around?
While I don't know that I think that it will make much of a difference, it wouldn't be much work to try that out.

Several actually. V1 and/or V2 right? not Phase inverter?

As for the defizzer pedal, I don't really do pedals generally, and I'd rather do amp-surgery than worry about pedals.

TylerDeadPine wrote: Tue Jul 25, 2023 10:24 pm Try another 470k resistor after C11, it's missing a voltage divider there (But has the grid leak so that's good) - but a 470k in series with the signal path is a significant drop, spec. high frequencies

The low-mids being weird/missing could be the 500k pots instead of the 1Meg on marshalls. you can try a 500k resistor in series with the pot pin because changing a whole pot can be a PITA sometimes depending on what you have to remove

Yeah, adding that 470k resistor seems like it's gonna happen. doubt I'll change the pots, but I'll keep that option in mind.

Not to harp again on the speaker - Jensen C12Ns sound great with a bandmaster, and if you're looking for a growly, balls marshall sound, absolutely not C12Ns at all.

They have a lot of different varieties, but generally 10" eminence speakers generally wouldn't be my first choice with a 2204 for mega-rock sound

TylerDeadPine wrote: Wed Jul 26, 2023 11:07 am Not to harp again on the speaker - Jensen C12Ns sound great with a bandmaster, and if you're looking for a growly, balls marshall sound, absolutely not C12Ns at all.

They have a lot of different varieties, but generally 10" eminence speakers generally wouldn't be my first choice with a 2204 for mega-rock sound

I appreciate the suggestions, but honestly, I don't want to get into swapping speakers. It's part of the signal chain I'd rather just work around. I wouldn't choose a 10" speaker for anything...until I got my bandmaster combo. It sounds nice and big and full with the 2x10's, like, better than I could have hoped. I'll give the stock speaker a chance with the circuit tweaks, and let the speaker just be what it is. If I still hate it I'll reconsider swapping...or just plugging the pig into a cab.

thecr4ne wrote: Wed Jul 26, 2023 12:11 pm

TylerDeadPine wrote: Wed Jul 26, 2023 11:07 am Not to harp again on the speaker - Jensen C12Ns sound great with a bandmaster, and if you're looking for a growly, balls marshall sound, absolutely not C12Ns at all.

They have a lot of different varieties, but generally 10" eminence speakers generally wouldn't be my first choice with a 2204 for mega-rock sound

I appreciate the suggestions, but honestly, I don't want to get into swapping speakers. It's part of the signal chain I'd rather just work around. I wouldn't choose a 10" speaker for anything...until I got my bandmaster combo. It sounds nice and big and full with the 2x10's, like, better than I could have hoped. I'll give the stock speaker a chance with the circuit tweaks, and let the speaker just be what it is. If I still hate it I'll reconsider swapping...or just plugging the pig into a cab.

Not advocating for you to change speakers, I say mod it however you like to make it work with what you’ve got, BUT back to the 2204. It originally came with greenbacks which are an inefficient, super dark and midrangey speaker. The amp was originally designed with that in mind. As time went on, the 2204 was paired with the Greenback’s successors. The G12-65, then the G12M-70, then the G12T-75. All of these have a treble diffusing mesh speaker dust cap that diminishes the harshness of the high end. By comparison the bandmaster is a very scooped amp. All of this is to say the 2204 was originally designed with a completely different speaker in mind. I hate it with American sounding speakers. But I love it with classic Celestions. It also sounds like an ice pick with Vintage 30s. It took me 20 years to come around to this amp having been a clean Fender ‘60s amp person for a long time. I had one a long time ago and hated it. Now I love it having embraced the idea of extreme settings, medium gain if I want to use pedals, and careful speaker choice.

Happy modding. I hope the sound improves for you.

thecr4ne wrote: Wed Jul 26, 2023 10:31 am So based on suggestions here and over in GroupDIY I'm planning to do the following:
First and foremost, take some measurements. I need to dig out my meter and scope and set up a space to work on this, but I'll go through and see if I can find anything wrong. Depending on the outcome of that, I think I'll then

-Recap (electrolytics) as preventative maintenance. Made in China~20 years ago doesn't instill confidence in quality control.
-Replace input jack with shorting switchcraft, and add the 68k grid stopper to V1A
-Remove C9 bypass cap on cold clipper
-Add 470K attenuator resistor between C11 and R15
-Replace R2 with 50K pot for variable bias, and add 1R cathode resistors to the power tubes for bias measurement.
-Generally inspect and touch-up solder joints as they don't look great at first glance.

Removing C9 was going to be my first suggestion. A cold clipper won't cold clip if the cathode is bypassed.

That pignose amps looks like someone made a bunch of "more gain" mods to the 2204 schematic without really listening or knowing what was going on.

That C21 bright cap looks like a shit show as well.

Cheers!
Ben

Was just putting flats on my Squier Jazzmaster, and something weird happened. The (wound) G wouldn't get up to pitch - or it would, but would immediately slide back down to F#. Did this again and again, cranking the tuner (for increasingly diminishing returns, if that makes sense) until eventually the string snapped at the point where it entered the safety tuner. Never experienced this sliding thing before.

What most likely caused this? Binding at the nut? Fucked tuner? Or defective string?

Dudley wrote: Thu Jul 27, 2023 2:23 pm Was just putting flats on my Squier Jazzmaster, and something weird happened. The (wound) G wouldn't get up to pitch - or it would, but would immediately slide back down to F#. Did this again and again, cranking the tuner (for increasingly diminishing returns, if that makes sense) until eventually the string snapped at the point where it entered the safety tuner. Never experienced this sliding thing before.

What most likely caused this? Binding at the nut? Fucked tuner? Or defective string?

I've seen this before and it has always been a problem with where the string winds around the ball end. It can unravel with tension. I will add that I've had nothing but problems with any and all flats that were not made by Tomastik. I'm done trying other flats. not sure if thats what you had, but I will say I've had maybe every 3/5 sets of diadario flats break when putting them on guitars and basses.

It may be that the core snapped invisibly under the winding - the G cores are very thin! - and that effectively un-anchored the end at the post. The tuner wraps would have held moderate tension to get to pitch, but slowly let go with playing.

thecr4ne wrote: Wed Jul 26, 2023 10:31 amSeveral actually. V1 and/or V2 right? not Phase inverter?

While it has been a good long while since I was around buds rocking that amp...

V1. Seems like the 5751 used to come up too. Don't know about the phase inverter.

Since "Harsh..." was coming up in those discussions, I've always leaned towards it just being that folks just can't face that they really are just not that into said design.

The only thing along that line that I can ever recall even being on the fence about was the Peavey VTM amps.