Who should I ask to mod JCM800 2204?

[Davey]

Re: Who should I ask to mod JCM800 2204?

thanks for the schems

[TwilightOdyssey]

Re: Who should I ask to mod JCM800 2204?

Brisk - I can't rave enough about the job that Jeff Seal did on my JCM800. I have the 2205 circuit.

Jeff, I didn't know you have a 2205 (same as me) ... I always thought you had the 100 watter!
How much butt does that amp kick?!!!

[Davey]

Re: Who should I ask to mod JCM800 2204?

just looked at the schems.. there's really not a lot in this amp... i had school projects that had more components (none of them worked properly, but thats a side note ROFL)

ok.. now does anyone have a picture/blueprint of the actual board? i'd hate to do this all point to point cos that'd be wire salad LOL, and where could i get the transformers? i got half of the components at home already.. all i'd need would be the tubes, sockets and transformers

[TwilightOdyssey]

Re: Who should I ask to mod JCM800 2204?

http://www.tubesandmore.com/

[Davey]

Re: Who should I ask to mod JCM800 2204?

coolness. i can get tubes here, but i'd like to get proper transformers cos thats pretty much the main part of any amp

thx man


sorry i hijacked the thread

[TwilightOdyssey]

Re: Who should I ask to mod JCM800 2204?

sorry i hijacked the thread

You went OT with TO!!

[Jeff_H]

Re: Who should I ask to mod JCM800 2204?

Jeff, I didn't know you have a 2205 (same as me) ... I always thought you had the 100 watter!
How much butt does that amp kick?!!!

Yup....I like the tone of the 50 watters much better, besides, in my den I'd never be able to turn the 100 watter up to get tube distortion....the 50 is bad enough.

I can't even begin to tell you how much it kicks. You'de have to play it to understand. The clean channel is really like a Fender Twin type clean. At times it's actually TOO clean and chimey for me....I have to throw in a little verb and back of the treble to warm it up.

The OD is seriously outstanding. Before mods my gain knob really had an effective sweep from 7-10...anything below 7 was really just volume reduction. Now the full range of the gain knob is effective, and I get outstanding AC/DC type crunch at a gain factor of 4 at tolerable room levels. Jeff also threw in a "quiet mode" or power reduction push/pull, lets me really crank things up at bedroom levels. I also have a bass boost function, a bright switch for the clean channel, a gain boost to take the amp into TSL gain territory (with the added noise of course). All without drilling the chassis or adding any switches....just a few push pulls.

Over the past few weeks I have noticed some additional hiss and channel noise that wasn't there before....this thing is usually almost dead quiet. I guess I need to check some pre-amp tubes to see if one of them is the culprit. If not I'm not sure what to do next....I guess I'll call Jeff.

[TwilightOdyssey]

Re: Who should I ask to mod JCM800 2204?

Sounds like a tube or two is dying ....
Playing loud isn't an issue for me ( ). I only had a power supply mod done to mine, to increase the current draw, which worked wonders, besides getting it pulled apart and put back together again.

Believe it or not, Jeff, the BIGGEST improvement to the head was putting in some early 70's Siemens NOS preamp tubes ... I can't believe how much better it sounds.

[Jeff_H]

Re: Who should I ask to mod JCM800 2204?

TO - I am a firm believer in NOS tubes. I have a NOS Bugleboy in V1 currently, an RCA Blackplate in V2, a German RFT in V3. V4 is a JJ as is my PI slot. My guess is one of my NOS tubes is starting to fart out. I don't have many hours on them, but NOS can be unreliable in life span.

I've got some new JJ's lying around that I'll probably throw in this weekend to see if that's the culprit. If not it may be time for power tubes, as the ones' I have are 18 months old or so. Again, not that many hours, but tubes are cheap, relatively speaking.

And what is this power supply mod? Is it something realitevly minor and inexpensive?

[TwilightOdyssey]

Re: Who should I ask to mod JCM800 2204?

I totally agree with you on the lifespan of an NOS tube.
For some reason, I've never been a fan of JJ tubes, even tho MANY guitar players in the know rave about 'em; I haven't auditioned them since about 2000 tho; do you know if they've done anything recently in production to improve 'em? I recall Svetlanas blowing 'em out of the water!

The work I had done on my 800 was by amp legend, Harry Kolbe. Harry's a great guy, but VERY slow!!! I had to threaten castration to get my 800 to me in time for a gig with Symphony X, LOL ...

I had an overahaul done, which is where he pulls it apart, does whatever repairs are needed, and resolders all the connections. Turns out I had a power cap that was starting to leak, and he had another 800, also from '85, right there, so he just used the caps from that one (at no extra charge).

The power supply mod is something I've only heard Harry speak of; in essence, with the increased current draw, the tranny acts like a boutique amp's tranny. (Like my Rivera) The whole repair, including the NOS tubes set me back only $300!!

Sadly, Harry recently stopped doing repairs and mods, as he's desiging a new amp line now, which is pretty hot -- Atomic amps, I think. This guy has done work for everyone: Yngwie, Satch, Iron Maiden ... his shop looks like a mad scientist's lair!

[Jeff_H]

Re: Who should I ask to mod JCM800 2204?

I don't know really if JJ has done anything to improve quality recently or not. I know that my NOS guy, Mike @ KCA stopped carrying them due to a 25% failure rate. I just happened to pick up 4 new JJ's from a board member for $20, just to have as extra's. I'll only put them in to see if the pre's are the problem. If they are then I'll order some more NOS tubes from Mike, or maybe try one of the GT-m's.

I'll check with Jeff Seal and Scott Splawn and see if either of them do power supply mods. I'd spend annother couple hundred if that would improve the tone. Not that I really need it to bang out AC/DC and VH riffs in my den, but I like to have the best tone I can....you never know when an opportunity to play with a group or even just jam will come up.