Dr Tony Balls wrote: Tue Jul 25, 2023 1:03 pm

thecr4ne wrote: Tue Jul 25, 2023 11:35 am I have a pignose G40V (similar in design to marshall 2204 I hear) that sounds pretty shrill to me. Like something's not there in the low-mid range, and the highs are murder. Tube swap didn't change this, Pots all do something, but I don't really know where to start to narrow down the cause. Any advice welcome. Schematic below.

1. correct in that its very 2204/2203
2. 2204s/2203s sound pretty shrill to me as is

Did it used to sound different and now it changed, or has it always sounded like this?

I never look at Marshall schematics, but it's weird to me that their is an extra gain stage before the EQ and not after it, is this for some sort of high gain distorto tonez? I'm only used to looking at Fender schematics, and V2 placement seems odd. Just wondering if that is how a Marshall is "Like" a Bassman, but not basically the same. Tone stack looks Fenderish.

thecr4ne wrote: Tue Jul 25, 2023 11:35 am I have a pignose G40V (similar in design to marshall 2204 I hear) that sounds pretty shrill to me. Like something's not there in the low-mid range, and the highs are murder. Tube swap didn't change this, Pots all do something, but I don't really know where to start to narrow down the cause. Any advice welcome. Schematic below.

I have a 2204 and with single coil Fenders and medium gain I run both the treble and presence knobs on 0. Bass and Mids around 5. If you are diming the preamp (or the mids and bass) or using humbuckers the treble knob is more useful. There’s a reason a lot of people clip the bright cap on these (which is directly soldered to one of the volume pots on the 2204).

Kniferide wrote: Tue Jul 25, 2023 3:01 pm I never look at Marshall schematics, but it's weird to me that their is an extra gain stage before the EQ and not after it, is this for some sort of high gain distorto tonez? I'm only used to looking at Fender schematics, and V2 placement seems odd. Just wondering if that is how a Marshall is "Like" a Bassman, but not basically the same. Tone stack looks Fenderish.

The lineage *roughly* goes like so...

1. Fender introduces the 5F6A Bassman which looks like: Gain Stage > Volume Control > CF Gain Stage > Tone Stack > LTPI Phase Inverter > Power amp.

2. Marshall copies with the JTM45 and it looks functionally the same: Gain Stage > Volume Control > CF Gain Stage > Tone Stack > LTPI Phase Inverter > Power amp.

(side note: both (1) and (2) have bright and normal channels that combine after the volume controls. by going down to one normal input, you have an extra triode of a tube to use)

3. Marshall revs their standard deisgn to suit the emerging heavier players: Gain Stage > Gain Stage > Volume Control > CF Gain Stage > Tone Stack > Master Volume> LTPI Phase Inverter > Power amp.

The 2203/2204 Marshalls just basically cascade the bright and normal channels together instead of having them in parallel.

Dr Tony Balls wrote: Tue Jul 25, 2023 1:03 pm Did it used to sound different and now it changed, or has it always sounded like this?

Honestly not sure. I picked it up years ago and it's been sitting for a long time and only recently seen any action. Since playing it recently, it feel very harsh on the highs, and the few vids of them I can find online sound less so, not that that's a real apples to apples comparison. Someone in another forum suggested a recap, so I'll probably start there just to make sure the electrolytics aren't causing weirdness.

Kniferide wrote: Tue Jul 25, 2023 3:01 pm I never look at Marshall schematics, but it's weird to me that their is an extra gain stage before the EQ and not after it, is this for some sort of high gain distorto tonez?

Marshall tone stack is post V2, Fender is mid V1. Both work though. It is pretty high gain, kinda too much so. After recap, I'm certainly considering adding in the "attenuator" as indicated in the above schem, and probably the V1 grid stopper as well.

(side note, my daily driver is a bandmaster reverb that I revoiced the "normal" channel to be marshally and cascaded for high gain, and the tone controls definitely feel different than a marshall, but it's not hard to get good sound from. See: https://robrobinette.com/Silverface_Amp ... hannel_Mod )

tommy wrote: Tue Jul 25, 2023 3:05 pm I have a 2204 and with single coil Fenders and medium gain I run both the treble and presence knobs on 0. Bass and Mids around 5. If you are diming the preamp (or the mids and bass) or using humbuckers the treble knob is more useful. There’s a reason a lot of people clip the bright cap on these (which is directly soldered to one of the volume pots on the 2204).

I have made these amps before and done them in both direct clone format and one with my personal mods to tame down all that brightness. Years later I had a chance to look at the Friedman Dirty Shirley schematic and lo and behold my mods look very similar to theirs. Makes it way more useful with a spectrum of guitars instead of just humbuckers.

FM four_oclocker_2.2 has one with the mods.

thecr4ne wrote: Tue Jul 25, 2023 3:53 pm

Dr Tony Balls wrote: Tue Jul 25, 2023 1:03 pm Did it used to sound different and now it changed, or has it always sounded like this?

Honestly not sure. I picked it up years ago and it's been sitting for a long time and only recently seen any action. Since playing it recently, it feel very harsh on the highs, and the few vids of them I can find online sound less so, not that that's a real apples to apples comparison. Someone in another forum suggested a recap, so I'll probably start there just to make sure the electrolytics aren't causing weirdness.

Dont recap it unless is humming. That wont solve the problem.

Look to what FM Tommy said. What pickups we using? Try rolling the treble all the way down and see if its better. It may not be broken, just MUCH MUCH brighter thank you think it should be.

Dr Tony Balls wrote: Tue Jul 25, 2023 4:00 pm Dont recap it unless is humming. That wont solve the problem.

Look to what FM Tommy said. What pickups we using? Try rolling the treble all the way down and see if its better. It may not be broken, just MUCH MUCH brighter thank you think it should be.

Well, My buddy was using his danelectro through it so I thought it was just that guitar's sound (lipstick pickups), the other guitar that we've tried is a gretsch jet with blacktop filtertrons that I think of as generally a bit less bright but it still comes through harsh on the high and dull on the lows. I'll pull something else out tonight so I can try with humbuckers and see how it behaves.

As for rolling back the treble, I've fucked around with the tone controls on the amp and can not get the harshness out. I think the closest was having high and mid at or near 0 and the bass around 5 or maybe, but like, it's marginally less painful, but not better sounding.

thecr4ne wrote: Tue Jul 25, 2023 11:35 am I have a pignose G40V (similar in design to marshall 2204 I hear) that sounds pretty shrill to me. Like something's not there in the low-mid range, and the highs are murder. Tube swap didn't change this, Pots all do something, but I don't really know where to start to narrow down the cause. Any advice welcome. Schematic below.

Have you tried plugging in a different speaker?

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.

One other thing...

While it's going to sound like I'm making this up?

Amptweaker make a pedal called the Defizzerator to address the issues with the Peavey 5150 if you put it in the effects loop.

Hearing what you are describing, it did come to mind.

Hard to find now, but it's a possibility.