1998 Jcm 2000 Dsl 100 Bias Drift Problems On All Units?

[glowrocks]

I'm about to buy a 1998 JCM 2000 DSL 100 amp and while tone wise (and price wise) this is the amp I'm looking for, all the articles about bias drift have me concerned.

The amp is said to be in fine working order, but little used.

I'm not sure everyone would notice bias drift, but since I'm aware of it, I would.

Any thoughts on how prevalent this problem is, especially w/an older unit?

It's on sale for $500, which is less than most Reverb offers, and so I wasn't planning on pushing on the price, but again ... bias drift.

Thanks!

 

[glowrocks]

Ah well, answering my own question, based on a bunch of reading, it very likely has the issue unless it's been previously repaired/modded.

It's still a better price than Reverb, but maybe those were newer units, after the problem was fixed.

I'll probably offer him $450 and buy the Dr Tube kit for 45 euros if necessary.

 

[ampmadscientist]

You are paying too much without knowing if it's been fixed the right way.

It can take a considerable amout of effort to get the bugs out of that amp. There are several other issues besides the bias drift.
Did you read:
http://www.marshallforum.com/threads/the-dsl-joey-mod-thread.13424/

 

[chiliphil1]

Yeah, scientist is right. I had one, a 1999 if I recall and it did have the drift issue. The amp seemed to play fine but over time it would start to sound worse and worse, one day I looked in the back and 1 tube was glowing red, I tried to shut it off but it blew the fuse before I could get to the switch. I did the dr tube kit and it completely cured the issues with bias but then it started having problems cutting out and sounding scratchy. To me those amps can be problem Childs of which I just don't want to bother.

What I would do if I were you and you're dead set on a DSL would be to buy a 2000 series made after 2005, or buy a Vietnamese DSL100H, they don't have the issues of the old one, everything has been corrected.

 

[Goldmember]

My JCM 2000 DSL 50 (made in 2000) has no bias drift issues. I did need to adjust the bias after replacing both power valves last year, but it has been rock solid gold. Shexshy and shmooth as a pancake!

 

[SG~GUY]

-The GOOD, The BAD & The UGLY-(love the old Clint Eastwood spegetti Westerns!!)-

-you've heard from the BAD, & The UGLY, guess its time for The GOOD!!-those early DSL 50/100's with DRAKE trannies are my favorite ones, they sound more like a MARSHALL....a lot more of that JMP/JCM TONE in its DNA, & it does have BALLS, from clean to mean, to a hot rodded 800!!

-there were problems with some of the PCB being thin boards close traces, and as the amp got warmer, it caused the bias to rise, and then the tubes got hotter, ,the tubes mounted to the board caused heat related issues, but its an easy fix, new board!! Poof! Done! easy to do your self, and the PCB's are not expensive!! And actually there are a few guys out there that sell a variety various versions of the PCB's, like stock, better components, vintage components & vintage voiced, and one offs, and in the same price range as a MARSHALL replacement! and there a chance, and a good one! That it's already been fixed!! I'd bring $400 and some lose change, TRY & BUY!!

 

[67mike]

I was told by many, that they revised the circuit in 2001 to fix those issues. So 2001 or newer are finr.

 

[glowrocks]

An hour in, and I LOVE THIS AMP!

My first Marshall, and (duh) quite unlike any of my Fenders (Champ, Princeton Reverb, Deluxe Reverb, Twin Reverb). Well, the cleans might be close to the Twin, but it's my least used amp, so can't say for sure.

The dirty channel is just amazing. I'm glad I finally got a Marshall, and despite the potential (easily dealt with) issues, I think I got the right one for me.

 

[Ghostman]

just more of a connection to be made to a chassis that is opened up and worked on.

Congrats, and Happy New Used Amp Day.

 

[devilRED]

I was told by many, that they revised the circuit in 2001 to fix those issues. So 2001 or newer are finr.

Mine is a 2001 model and had the bias drift problem, bought a new pcb to fix it

 

[johan.b]

You can Get your replacement pcb here.
https://www.proaudioservice.co.uk/product/marshall-dsl100-amp-pcb-board-jcm2-60-00-100w/
Is the best price I've found. Service was fast when i ordered.
The fact that you CAN buy a replacement pcb, to me, is a silent recognition there was an issue with the early pcb's ..i didn't have an issiue with my 1998 DSL. But it was easier to replace the pcb than buying new caps and doing all the work when i thought it was time for a cap job
J

 

[RickyLee]

An hour in, and I LOVE THIS AMP!

My first Marshall, and (duh) quite unlike any of my Fenders (Champ, Princeton Reverb, Deluxe Reverb, Twin Reverb). Well, the cleans might be close to the Twin, but it's my least used amp, so can't say for sure.

The dirty channel is just amazing. I'm glad I finally got a Marshall, and despite the potential (easily dealt with) issues, I think I got the right one for me.

I had a DSL100 made in 2005 for many years. It was not one of the "special" ones out of the factory as it had a bad fizzy character and the Red channel was so much brighter than the Green channel that it was very unpleasant to play much less try to use as a channel switcher. I ended up modding the shiznot right out of it.

Then a few years later I scored a '98 DSL100 for an incredible price. That amp right from the factory was what I think all these amps were intended to sound like when they designed this line. Red channel was the highlight on this one.

So, it sounds like maybe you got one of the above average ones as well. Congrats. And what a big difference from playing those old Fenders, huh?

EDIT/ADD: I forgot to mention as per thread title, I have not had any bias drift issues to date on this 1998 DSL100.