'76 Marshall JMP 2203 with Custom High Gain Mod

[Eddylenz]

Hi Everyone,

I just finished modding this amp with a custom 4 stage non-cf high gain mod. It's based on the gain channel of my 2 channel prototype, but I've tweaked it for a long time. It also has a tube fx loop.

There's a bass shift switch on the bass pot, a mid voicing switch on the gain pot, and a gain structure switch, that takes away some saturation.

It can do crunchy 70s, 80s Hard Rock/Metal, and more modern Metal sounds.

Let me know what you think!

 

[Old Punker]

Wow! If you are going straight into the amp then you have created a Metal Monster!
Sounds great with all of those guitars too.

 

[Eddylenz]

Wow! If you are going straight into the amp then you have created a Metal Monster!
Sounds great with all of those guitars too.

Thanks!
It's straight in

 

[bigbadorange]

Freaking awesome, right up my alley! I for sure hear detuned, and/or possibley a 7 string?

 

[Eddylenz]

Freaking awesome, right up my alley! I for sure hear detuned, and/or possibley a 7 string?

Thanks! I used my Charvel in Drop C with 10-52 for the intro

 

[southbound suarez]

Very interesting!
I have an old 77 2203 that was Demeter Modded according to the label stuck upon the rear.
It is stored in back on a pile of future amp projects.
I just had a newer 2203 across the bench last week and was impressed with how well and how good the tone was for a master volume amp. It had me jonesing on that old 2303 that I have as a project. Now I must go dig it up and see what was done with it... I know that it had been modded into dual foot switchable channels and utilizes dual gang pots with inner and outer shafts . Switching handled by a perf board loaded with several vactrol optical devices.... Hmmm???
I never was a fan of master volume amps but that last stock 2203 has me intrigued and now this..
Forgive my ignorance but you mentioned "non CF gain mod" what is CF Gain?

 

[Marshall50w]

Sounds awesome, all the sounds from great cleanish crunch through to glorious all out. Now I get the 'riding the volume pot' ! not forgetting, proper great playing.

 

[Eddylenz]

Very interesting!
I have an old 77 2203 that was Demeter Modded according to the label stuck upon the rear.
It is stored in back on a pile of future amp projects.
I just had a newer 2203 across the bench last week and was impressed with how well and how good the tone was for a master volume amp. It had me jonesing on that old 2303 that I have as a project. Now I must go dig it up and see what was done with it... I know that it had been modded into dual foot switchable channels and utilizes dual gang pots with inner and outer shafts . Switching handled by a perf board loaded with several vactrol optical devices.... Hmmm???
I never was a fan of master volume amps but that last stock 2203 has me intrigued and now this..
Forgive my ignorance but you mentioned "non CF gain mod" what is CF Gain?

Nice! It would be really interesting to hear that one.

CF is cathode follower. This one has a plate-driven tone stack.

 

[solarburn]

Hi Everyone,

I just finished modding this amp with a custom 4 stage non-cf high gain mod. It's based on the gain channel of my 2 channel prototype, but I've tweaked it for a long time. It also has a tube fx loop.

There's a bass shift switch on the bass pot, a mid voicing switch on the gain pot, and a gain structure switch, that takes away some saturation.

It can do crunchy 70s, 80s Hard Rock/Metal, and more modern Metal sounds.

Let me know what you think!

I hate reverse headstocks. The rest of the guitar is kill.

My mutherfucker knows how to tune a vintage Marshall. Sounds really wet without any lube. Sticky when you want.

Still? I prefer my Metal zone.

That shit does what I'd want a JMP to do. Loved the Lynch! I'll take 2!

 

[Eddylenz]

Sounds awesome, all the sounds from great cleanish crunch through to glorious all out. Now I get the 'riding the volume pot' ! not forgetting, proper great playing.

Thanks haha!

I love reverse headstocks and hate Metal Zones ;D

 

[solarburn]

Thanks haha!

I love reverse headstocks and hate Metal Zones ;D

That amp sounded so good. Killer!

 

[dslman]

Sounds great!! Very aggressive also.
Do you mind me asking what bright cap value, you have on the amp?
Thank you.

 

[Eddylenz]

Sounds great!! Very aggressive also.
Do you mind me asking what bright cap value, you have on the amp?
Thank you.

Thanks!
There's no bright cap on the gain pot. I always try to design my circuits without one, so you can really use the gain control as a gain and not a fatness control.

 

[dslman]

Thanks!
There's no bright cap on the gain pot. I always try to design my circuits without one, so you can really use the gain control as a gain and not a fatness control.

Wow, that’s pretty impressive then. Great work!

 

[Eddylenz]

Wow, that’s pretty impressive then. Great work!

Thank you!