Marshall JCM800 Bass Series mods?

[MR MARCUS]

I just picked up a Marshall JCM800 Bass for cheap($900 shipped). I think I want to mod it but I heard some are worth a good bit of money. Mine is a 50 watt with 6550's and verticle inputs. I could do the master volume mod myself. I haven't had a chance to look at the schematic to see if anymore "simple" mods are possible.

 

[BSRIAudio]

The bass models are pretty different from the guitar models. They have a different tone stack and gain structure. Its not like a Superbass vs. Superlead thing. If you're looking for a modded 800 sound you would be better off starting with something in the standard 2203 architecture.

 

[MrDan666]

Yup you'll have to gut it and install a new circuit board if you plan on doing that stuff. In stock form, they aren't like a SuperBass.. They're an actual bass amp preamp circuit, with a 2203 power section.

I've modified plenty of them, but it was really a rebuild more than a mod. I'm talking completely new preamp circuit, all new pots/jacks/components, different filtering etc. Not a simple job!

Cheers,
Dan

 

[MR MARCUS]

Yup you'll have to gut it and install a new circuit board if you plan on doing that stuff. In stock form, they aren't like a SuperBass.. They're an actual bass amp preamp circuit, with a 2203 power section.

I've modified plenty of them, but it was really a rebuild more than a mod. I'm talking completely new preamp circuit, all new pots/jacks/components, different filtering etc. Not a simple job!

Cheers,
Dan

Damn!.!. I read otherwise. With this coming from you I know I read wrong. Maybe I can flip it.

 

[sjk]

Yup you'll have to gut it and install a new circuit board if you plan on doing that stuff. In stock form, they aren't like a SuperBass.. They're an actual bass amp preamp circuit, with a 2203 power section.

I've modified plenty of them, but it was really a rebuild more than a mod. I'm talking completely new preamp circuit, all new pots/jacks/components, different filtering etc. Not a simple job!

Cheers,
Dan

Damn!.!. I read otherwise. With this coming from you I know I read wrong. Maybe I can flip it.

Or just sink a little more money into it and install this, and then if you want to mod it you have a great mod platform!
https://www.ebay.com/itm/281507894745?_t ... EBIDX%3AIT

 

[glip22]

I'd flip that amp. Not worth dropping several hundred more

 

[MR MARCUS]

Why did Adam Jones like the JCM800 Bass? Super disappointed!!!!!

 

[smdb]

Yup you'll have to gut it and install a new circuit board if you plan on doing that stuff. In stock form, they aren't like a SuperBass.. They're an actual bass amp preamp circuit, with a 2203 power section.

I've modified plenty of them, but it was really a rebuild more than a mod. I'm talking completely new preamp circuit, all new pots/jacks/components, different filtering etc. Not a simple job!

Cheers,
Dan

I just traded for one of these modded by Dan Gower to a KK++.. It's an awesome sounding amp!

 

[RJF]

Why did Adam Jones like the JCM800 Bass? Super disappointed!!!!!

I don't like Marshalls, but even I think I can answer this one. The Superbass is not an actual bass amp. What you bought is an amp that is actually a full on bass amp, for bass guitars.

 

[BSRIAudio]

Why did Adam Jones like the JCM800 Bass? Super disappointed!!!!!

He was using a Superbass, not a JCM800 1992 bass model. He was also running it with two other amp heads so it was only part of the tone. A JMP Superbass is only a few values away from a Superlead. A 1992 is a completely different type of amplifier from a 2203/2204.

 

[MR MARCUS]

Jerry P said he can mod it.