JCM 900 50 watt head comments

[ErikH]

Re: JCM 900 50 watt head comments

Well, Dave (theodie) knows this amp pretty well too. I'm just sort of an activist for a better reputation of it so to speak..LOL.

Anyway, the tubes I was recommended from my tech are Svetlana EL34's and EH 12AX7's. They sound great and made it sound like a new amp. I'm not a big Groove Tubes fan. If you're not sure when it was retubed last, better to spend the extra cash now and get it done with a complete bias/cleaning. The pots just need cleaning, easy to do there and the tech will do that while the chasis is out to bias it. After the check-up/tune-up, she'll purr like a kitten but roar like a lion...LOL.

 

[Vasshu the humanoid typhoon]

Re: JCM 900 50 watt head comments

ok no burning then
Just burn on them then

 

[theodie]

Re: JCM 900 50 watt head comments

The tubes I use in my 2100 are Sovtek WXT EL-34's and Sovtek LPS 12AX7's. I didnt like JJ's that much (they were OK) and EH's were just OK IMO. The Sovteks were the winner by a decent margin!

 

[thucydides]

Re: JCM 900 50 watt head comments

As long as we're on 900s, has anyone retubed Dual Reverbs w/EL 34s? What, if any, improvement was there?

 

[ErikH]

Re: JCM 900 50 watt head comments

As long as we're on 900s, has anyone retubed Dual Reverbs w/EL 34s? What, if any, improvement was there?

Actually, the Dual Reverbs came with EL34's from their introduction in 1990 up through the model line wide change over to 5881's in late 1993 / early 1994. Changing the 5881 equipped models will require some changes in the power amp section though. It's not an even swap.

 

[thucydides]

Re: JCM 900 50 watt head comments

Thanks, EricH. I ask because I have a Dual Reverb w/5881s, and I'm not happy with it. I have a pretty good tech, but are the power amp mods problematic, or should it not be such a big deal for an experienced tech? Soundwise, will it take me back to a beefier Marshall tone? My 900 Dual Reverb is way too thin! I'm thinking that it might be cheaper to mod what I have, rather than dump it, and get a different model. But, if it is better to dump it, and get a different model, I'm quite willing to do that!

 

[ErikH]

Re: JCM 900 50 watt head comments

Thanks, EricH. I ask because I have a Dual Reverb w/5881s, and I'm not happy with it. I have a pretty good tech, but are the power amp mods problematic, or should it not be such a big deal for an experienced tech? Soundwise, will it take me back to a beefier Marshall tone? My 900 Dual Reverb is way too thin! I'm thinking that it might be cheaper to mod what I have, rather than dump it, and get a different model. But, if it is better to dump it, and get a different model, I'm quite willing to do that!

With EL34's the dirty channel on those is really nice. It should be simple work for an experience tech. I'm not an experience tech but swapping some resistors and changing the socket wiring a little bit doesn't look too bad to me. All they need is the schematic of the EL34 version. Go to http://www.drtube.com/marshall and go to the JCM900 section. There you'll find schematics for both version. This guy is really nice.