Thinking Of Converting My JCM 800 - Advice / Suggestions

Jeff_H

Dean Hardtail Fanologist
I have a 2x12 combo that started life as a JCM800 4212 (2205 circuit in a combo), 2 channels. About 2 1/2 years ago, I sent it to Jeff Seal to be modded. What he did was completely remove the PCB board from the amp and constructed a new PTP wiring scheme inside the chassis using the existing chassis, transformers, tube sockets, ect. When I got the amp back, I also got the old JCM 800 PCB board back, intact with pots, ect...just removed from the amp.

What I would really like to do is take the new amp (wiring scheme) that Jeff created and put it into a head version, convert the 2x12 back to stock JCM 800 and probably sell it. I can probably get enough from the sale of the "stock" JCM 800, in the condition that it's in, to either pay for all of these changes + some extra, or to fund the purchase (at least partially) of a new/custom amp. I am aware that if I do this, I'll need a new chassis, head enclosure, trannies, faceplate, ect to "drop" Jeff's innards into.

My question is this. Worth it? How much do you think it would cost? I know I can get empty Marshall head cabs, new chassis, ect for not a ton of money. Good trannies will cost a bit, but not sure how much.

Opinions and advice would be welcome.
 
Re: Thinking Of Converting My JCM 800 - Advice / Suggestions

How much of a drag would it be to make the 800 "stock" again?

I'm guessing the PCM was stripped or at least partially stripped?
 
Re: Thinking Of Converting My JCM 800 - Advice / Suggestions

Maybe something like this.....$275 doesn't seem too bad for a head cab that looks like this.

bordmar1.jpg
 
Re: Thinking Of Converting My JCM 800 - Advice / Suggestions

How much of a drag would it be to make the 800 "stock" again?

I'm guessing the PCM was stripped or at least partially stripped?

Actually, the entire PCB was removed intact, so it would just need to be "reconncted" to the output trannies, tube socets & power. Nothing was stripped, removed or altered. Jeff did this specifically so if I ever wanted to take it back to stock, it would be a drop in procedure.
 
Re: Thinking Of Converting My JCM 800 - Advice / Suggestions

Ahhhhhhhhhh.

Schweet!



That head cab looks KILLER!

But would you ever want to take it out of the house to a bar gig???
 
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Re: Thinking Of Converting My JCM 800 - Advice / Suggestions

Jeff, As you may know? I built my own 2204. Plexi/JTM chassis are readily available. But I has a hard time locating a JMP/JCM 2204 chassis. I Imagine a 2205 chassis would be even tougher to scare up. I ended up having my chassis custom made for me by a guy in Texas. Trannie's for that amp will run around $100+ a piece the choke will be around $25.
 
Re: Thinking Of Converting My JCM 800 - Advice / Suggestions

Personally, I'd just buy that head cab and the proper chassis, switch it over, then you'll have a killer halfstack with that cane grill Marshall 4-12.

As for the combo cab and spare parts. Just sell it off. Too much of a hassle to rebuild it, if you can't do it yourself.
 
Re: Thinking Of Converting My JCM 800 - Advice / Suggestions

Jeff, As you may know? I built my own 2204. Plexi/JTM chassis are readily available. But I has a hard time locating a JMP/JCM 2204 chassis. I Imagine a 2205 chassis would be even tougher to scare up. I ended up having my chassis custom made for me by a guy in Texas. Trannie's for that amp will run around $100+ a piece the choke will be around $25.

Ken, do you have a link to the guy you got your head cab from?

Personally, I'd just buy that head cab and the proper chassis, switch it over, then you'll have a killer halfstack with that cane grill Marshall 4-12.

As for the combo cab and spare parts. Just sell it off. Too much of a hassle to rebuild it, if you can't do it yourself.

Joe, It should be a simple job for someone with soldering skills, and an understanding of amps, but that's def not me. I was thinking that if I could convert the old one back using all the existing parts, and then just get a new head cab/trannies/choke/chassis for Jeff Seal's circuit, all for around $500 or so it would be worth it.

I could sell the "stock" JCM800 combo w/new grillcloth on eBay for around a grand I think. Then I'd be $500 ahead, but not sure I can do the project for $500 total.

Just tossing the idea around. I should really PM Scott and see how much labor is involved in switching the two out. That will probably be the key factor, not cost of parts.
 
Re: Thinking Of Converting My JCM 800 - Advice / Suggestions

Ken, do you have a link to the guy you got your head cab from?
My Dad made my Head box for me :D My Chassis was made by R.Work of Bay City,TX I have his contact info somewhere? If ya need it? I'll find it for you.:) My Dad did a nice job on the cab. It looks cool, But it's light years away from being Pro Quality.:fingersx:
 
Re: Thinking Of Converting My JCM 800 - Advice / Suggestions

For a minute there I thought you were gonna sell a Jeff Seal creation (gasp!). I was worried.

Don't speak blasphamy Chops. I want to IMPROVE it. Too bad Jeff is soooo busy and not doing custom amp work any longer. I'd just send it back to him for the conversion.
 
Re: Thinking Of Converting My JCM 800 - Advice / Suggestions

Yeah...it's classy...

But I don't know if I'd gig with something like that.

Part of me would be thinking "DAMN...what if I get a scratch on that fine piece 'o furniture..."

And the OTHER half of me is thinking about all those old Boogie Mark 1x12's that are ALLLLLLLLLLL worn down, look RAD and fukkin' kick ass!






Besides....who wants THAT tasty wood when you could have a beat-to-crap Sound City 120 as a frame!

:chairfall
 
Re: Thinking Of Converting My JCM 800 - Advice / Suggestions

A piece of furniture like is fine if you never play out of your colonial home, but it doesn't look very roadworthy to me.

Jeff, you might want to pop the chassis out of the combo and stick it in a custom made head. Then a new faceplate or everything will be upside down et voila, you have a head you can take with you and a 2x12" cab at home so your huge cab(s) can stay in the studio.

Shoot me a PM if you want some desings on cab/face-/rearplate. Your chance to get all those new functions with push/pulls on the faceplate without whipping out the Dymo. ;)

Remember these ?
http://members.home.nl/vincenteisen/newamp/
 
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