Marshall Guvn'r Plus 2 - C22 'mod'

Voxman

I'm aware that by snipping one of the legs off the C22 cap, you can greatly enhance tone and make the pedal brighter/tighter.

I was wondering if anyone has done this simple mod, and just wanted to check that all the tone/bass/mid/deep controls all still work after the 'mod' (so you can still make the pedal sound darker if you wanted to) and that there are no unwanted side-effects eg more noise?

ThePrettyDamned

I did it, and didn't like the result, so put it back. 

The tones are all already there in my opinion, it's a pedal that works best up loud vs at home volume. The main weakness I wanted to fix was the ability to clean up through pick attack - it's not fantastic for that, but the actual sound is so good I didn't mind. 

Grumpyrocker

I did this mod. It certainly makes it brighter, but I didn't like the result.

Voxman

Interesting @Grumpyrocker and @ThePrettyDamned - I think that's the first time I've read negative responses to the C22 mod.

I agree that it's best 'cranked' but what was it exactly about the changed tone that you both didn't like?

@ThePrettyDamned I note you put it back - was it not possible to dial back in the 'pre-mod' tone with the effect controls?

ThePrettyDamned

Voxman said:

Interesting @Grumpyrocker and @ThePrettyDamned - I think that's the first time I've read negative responses to the C22 mod.

I agree that it's best 'cranked' but what was it exactly about the changed tone that you both didn't like?

@ThePrettyDamned I note you put it back - was it not possible to dial back in the 'pre-mod' tone with the effect controls?

You might be able to, but I struggled to dial it in. It just makes it brighter - it doesn't 'open up' the slightly congested sound (which is fairly accurate imo of 70's rock). 

It's just a pedal that needs to be loud to make more sense. I don't usually like that sentiment, but it's really true of the GV2. Max gain, volume up a bit, careful with the bass and the resonance or whatever it's called (which is easily the best bit of the pedal) and scoop some mids. Keep the treble up a bit and that's a really excellent old school marshallish tone. 

Yorkie

With apologies in advance for digging this out. I have just received a GV2 I found for £30 on eBay. Have no idea if it’s been modded, but will find out later. My question is about the settings to make this sound like early AC/DC; I have read that you need to keep gain low and crank up the mids, but @ThePrettyDamned said that this (unmodded) pedal works best with gain cranked up. Is the mod worth doing if wanting to keep gain low? 

Cheers,
Jon

Voxman

Yorkie said:

My apologies in advance for digging this out. I have just received a GV2 I found for £30 on eBay. Have no idea if it’s been modded, but will find out later. My question is about the settings to make this sound like early AC/DC; I have read that you need to keep gain low and crank up the mids, but @ThePrettyDamned said that this (unmodded) pedal works best with gain cranked up. Is the mod worth doing if wanting to keep gain low? 

Cheers,
Jon

The C22 mod simply makes the GV2 a little brighter. I've not done it to mine as I have a Boss G7 EQ at the end of the signal chain on my pedalboard that gives me extra EQ control. 

ThePrettyDamned

Just play it and see what you think. I think you'll be surprised.

It's not a high gain pedal. 

Yorkie

I think I’ll have to reset the Katana’s EQ. I had increased the bass response to suit my taste, but now the combination with this thing’s ‘deep’ sound is making the headphones shake. 

Jon

Voxman

Yorkie said:

I think I’ll have to reset the Katana’s EQ. I had increased the bass response to suit my taste, but now the combination with this thing’s ‘deep’ sound is making the headphones shake. 

Jon

The deep control is what makes the GV2 sound like it's going through a 4x12! 

smudge_lad

I have two GV2’s - one modded and one un-modded. As previously stated, the mod definitely makes the pedal brighter, and personally I prefer the modded pedal.

The biggest flaw of the pedal is with the gain low. It’s just doesn’t react well at all, which is a real shame. Gain cranked to mid/high gain, it absolutely wails! 

I don’t think I’ve ever tried rolling the guitar volume off though, which might work. But running the pedal itself in lower gain sounds really bad unfortunately 

Voxman

smudge_lad said:

I have two GV2’s - one modded and one un-modded. As previously stated, the mod definitely makes the pedal brighter, and personally I prefer the modded pedal.

The biggest flaw of the pedal is with the gain low. It’s just doesn’t react well at all, which is a real shame. Gain cranked to mid/high gain, it absolutely wails! 

I don’t think I’ve ever tried rolling the guitar volume off though, which might work. But running the pedal itself in lower gain sounds really bad unfortunately 

That's very odd. My GV2 sounds good at all gain levels. My amps are a Laney Cub12R, Laney VC30-210, Marshall Valvestate Mk1 8080, and Marshall JCM2000 DSL401. 

Im aware that different distortion pedals sound better with different amps. You wouldn't be going through a Fender per chance? 

smudge_lad

Voxman said:

smudge_lad said:

I have two GV2’s - one modded and one un-modded. As previously stated, the mod definitely makes the pedal brighter, and personally I prefer the modded pedal.

The biggest flaw of the pedal is with the gain low. It’s just doesn’t react well at all, which is a real shame. Gain cranked to mid/high gain, it absolutely wails! 

I don’t think I’ve ever tried rolling the guitar volume off though, which might work. But running the pedal itself in lower gain sounds really bad unfortunately 

That's very odd. My GV2 sounds good at all gain levels. My amps are a Laney Cub12R, Laney VC30-210, Marshall Valvestate Mk1 8080, and Marshall JCM2000 DSL401. 

Im aware that different distortion pedals sound better with different amps. You wouldn't be going through a Fender per chance? 

No, currently using a JVM410h and a Bad Cat Black Cat 30. 

I just don’t like the way it responds with the gain low. It just doesn’t seem very alive and maybe a bit flat. It definitely doesn’t sound like my Marshall or other MIAB pedals with the gain set low

relic245

Voxman 

Im aware that different distortion pedals sound better with different amps. You wouldn't be going through a Fender per chance? 

I think the gv2 sounds ace through a fender. At least it does through my hrd with a v30 in.

Grumpyrocker

I haven't used my GV2 for ages. My Tone City Model M does the Marshall in a pedal thing so much better. 

thermionic

I read somewhere that they copied most of the tone stack from the original Guv’nor, but scaled down all the resistor and capacitor values by a factor of 10 - but they forgot to change C22, which is ten times too big. Replacing it with the “correct” value should in theory yield better results than removing it completely. Maybe I’ll try it one day…

Yorkie

Voxman said:

Yorkie said:

I think I’ll have to reset the Katana’s EQ. I had increased the bass response to suit my taste, but now the combination with this thing’s ‘deep’ sound is making the headphones shake. 

Jon

The deep control is what makes the GV2 sound like it's going through a 4x12! 

That’s what the manual says, yes. But with the Katana’s EQ set to boost bass too, the whole thing was displacing an unsettling amount of air. I shall reset it tomorrow when I have access to a computer. 

Jon

Yorkie

thermionic said:

I read somewhere that they copied most of the tone stack from the original Guv’nor, but scaled down all the resistor and capacitor values by a factor of 10 - but they forgot to change C22, which is ten times too big. Replacing it with the “correct” value should in theory yield better results than removing it completely. Maybe I’ll try it one day…

I’ve also read that they left C22 as it was because a lower capacitance would cause problems with feedback (?) because of the way cables are bundled inside the pedal… having just opened mine (unmodded, btw) I can only nod. But the board is soooo neatly annotated. I like it

Edit: here is the source - https://www.marshallforum.com/threads/marshall-gv2-guvnor-plus-overdrive-distortion-pedal-how-it-works-mods.93225/

thermionic

Interesting stuff, thanks @Yorkie. Lots of clever stuff going on in that pedal, almost makes me feel nostalgic for running Spice simulations!

Yorkie

thermionic said:

Interesting stuff, thanks @Yorkie. Lots of clever stuff going on in that pedal, almost makes me feel nostalgic for running Spice simulations!

Me too! It’s been a while… 

andy_k

Good read, I always preferred the Mk 1, so it is interesting to see how the circuit differs. I'm sure all the tone is in the Mk2, it is just a bit harder to dial in, option paralysis sets in, and I have settled on using a Fuzzdog Angry Andy for my MIAB pedal.
It is quite amazing how versatile that pedal is (based on a JHS AT model) considering how few parts are in the circuit, and the way the tone circuit is set with just 2 knobs makes things simple. There is a 3 way switch to set 25 / 50 / 100watt  headroom which has fairly drastic effects.