I Own a 1992 4100 DR el-34 model that I bought few months ago , doomed with 3 IC's completely dead, no sound, for 300€, so ... Did upgrade all of them, full recap, couple of mods, bright caps, upgrading gain stages.. etc .. now I love it and it's a keeper .. underrated sleeper amp in the market... A real high gain monster... Specifically great on downtuned C# tuning....
I had a JCM 900 Dual Reverb that I bought new back in the 1990s. That thing ate tubes right and left, something that I put up with for about 20 years before I gave up. Fortunately, the board is easy to work on, otherwise not sure what my repair bills would have been (Laney AOR or Mesas - cough - are much more difficult to work on).
great amp, i use cliff stereo jack instead of mono jack and cut the middle lug pcb leg with a flush cutter, it helps to hold the input cable tip better. Thanks for your video.
I looked but didn’t see any. I usually replace that bridge anyway in these, get the new one up in the air. I didn’t mention in the video that R30 is toasty too.
My 2100 once had to be serviced because it was not turning on. I dont know what they did besides having a new tube set. One day I opened the amp and I noticed there was a big burnt hole right next one of the output jacks. The techiciant managed to re-routed it somehow and it got fixed. Thats what you say at 4'30'' ? I always though that someone tried to play it without a load in the rehearsal room...
Hey! Could I ask a couple quick questions? I'm thinking about replacing every single Cap on my JCM 900 4100 DR Head, and likely the Cement grid resistors, and just curious what your thoughts would be on just essentially re-doing the whole board, including all the resistors etc? For me, because it's an Amp I use a lot, and It's basically going on 25 years old, it would be more as a preventative maintenance kind of thing, plus there's also a few Components I wanted to replace anyway, including the jacks, so was just thinking maybe it's better just to do it all in one go, and since I have the time. It's also been a solid amp, and I've never had any real issues. It was definitely at the point a few years ago it totally needed new Can Caps, but the LCT's looked okay still, but I could just tell by the way it sounded, and it was noisy. After doing the Caps it was back to the Amp I loved, and super quiet. But yeah, basically just curious about your thoughts on an overhaul, and if you think there's anything that's not worth doing, or if you have any opinions/feedback? Cheers!
Nice, I'm restoring one at the moment! I've read a lot about the infamous BR3 on forums, but what's the best approach to correct that overheating issue? I'm thinking upgrading C8's voltage rating a bit and leaving CR3 alone (mine has a RC201 at the moment 2A/50v, not sure if that's the original part since the amp has been previously modified). Cheers from Mexico.
Well shit, Digikey sent the wrong part. Now waiting for a new Mouser shipment. Anyway, I replace BR3 with a new 2W02 2 amp bridge mounted about an inch off the board for better heat dissipation. I do this to all three bridges in this model, though BR3 is the main offender as far as heat damage goes. If the old bridge burned the board/pads/traces too badly, I install a larger bridge screwed to the chassis and run wires to the necessary points on the PCB.
@@PsionicAudio awesome, so in case I have to go with an off board bridge I guess it would not hurt going with a bigger voltage rated one if it's still 2A? Thanks for the info!
But it's premium! By the way your discussion of PI cap leakage and what can happen goes a long way toward explaining how the 400v caps Mesa uses in this section are underrated for the job.
I've owned one like this for years! He just stood around in the corner:-( I regret having bought it, it's a very boring amp. The preamp only works with full distortion. And the idea of 2 switchable power amps..can be nice..But doesn't do much. When I bought it in 1992, the seller said to me "Better buy the JCM 900 High Gain Dual Reverb. It's more versatile and just better". ...He was right ! I now have a JCM 900 High Gain Dual Reverb...and this is the best I've made!
Most forum warriors seem to think that the SLX and Mkiii is so much better than the Dual Reverb because of the diode clipping in it. Do you think it makes a notable difference since you’ve owned both models?
its likely that the one that you heard was out of spec. literally millions of guitar players are in line to " demand satisfaction " from your statement,,myself included
Thank you for saving another amp. Family, videos, and music is all that is left that is good in this world.
Pretty much.
I Own a 1992 4100 DR el-34 model that I bought few months ago , doomed with 3 IC's completely dead, no sound, for 300€, so ... Did upgrade all of them, full recap, couple of mods, bright caps, upgrading gain stages.. etc .. now I love it and it's a keeper .. underrated sleeper amp in the market... A real high gain monster... Specifically great on downtuned C# tuning....
Wow, what a clean break in the PI tube. Couldn't have done that had you tried.
I had a JCM 900 Dual Reverb that I bought new back in the 1990s. That thing ate tubes right and left, something that I put up with for about 20 years before I gave up. Fortunately, the board is easy to work on, otherwise not sure what my repair bills would have been (Laney AOR or Mesas - cough - are much more difficult to work on).
Man you know all your stuff very well. Makes me want to ship my two Peavey heads to you!
Was my first guitar amp way back in 1999. Bought a Marshall Slash 4X12 cab from Simon McBride, the new guitarist for Deep Purple.
I love this amp. Looks pretty nice inside.
great amp, i use cliff stereo jack instead of mono jack and cut the middle lug pcb leg with a flush cutter, it helps to hold the input cable tip better. Thanks for your video.
Spoilers!
I do the same. ;)
Marshall 1974x sometime in the future?
My favorite amp of the 90’s when I was playing heavy shit. Mine was modded. Wish I still had it.
Notice any burning / hot spots around the rectifier for the DC heaters (BR3)?
Yeah this is a super common failure mode in the SL-Xs.
I looked but didn’t see any. I usually replace that bridge anyway in these, get the new one up in the air.
I didn’t mention in the video that R30 is toasty too.
My 2100 once had to be serviced because it was not turning on. I dont know what they did besides having a new tube set. One day I opened the amp and I noticed there was a big burnt hole right next one of the output jacks. The techiciant managed to re-routed it somehow and it got fixed. Thats what you say at 4'30'' ?
I always though that someone tried to play it without a load in the rehearsal room...
Hey! Could I ask a couple quick questions? I'm thinking about replacing every single Cap on my JCM 900 4100 DR Head, and likely the Cement grid resistors, and just curious what your thoughts would be on just essentially re-doing the whole board, including all the resistors etc? For me, because it's an Amp I use a lot, and It's basically going on 25 years old, it would be more as a preventative maintenance kind of thing, plus there's also a few Components I wanted to replace anyway, including the jacks, so was just thinking maybe it's better just to do it all in one go, and since I have the time.
It's also been a solid amp, and I've never had any real issues. It was definitely at the point a few years ago it totally needed new Can Caps, but the LCT's looked okay still, but I could just tell by the way it sounded, and it was noisy. After doing the Caps it was back to the Amp I loved, and super quiet. But yeah, basically just curious about your thoughts on an overhaul, and if you think there's anything that's not worth doing, or if you have any opinions/feedback?
Cheers!
a 4 tube jcm 800 basically. underrated amp.
Plastic jackshave NEVER been a good idea.🤔
Thanks for the look inside of this Marshall. 😎👍
Nice, I'm restoring one at the moment!
I've read a lot about the infamous BR3 on forums, but what's the best approach to correct that overheating issue?
I'm thinking upgrading C8's voltage rating a bit and leaving CR3 alone (mine has a RC201 at the moment 2A/50v, not sure if that's the original part since the amp has been previously modified).
Cheers from Mexico.
Stay tuned, hopefully later today. Waiting on a parts delivery.
Well shit, Digikey sent the wrong part. Now waiting for a new Mouser shipment.
Anyway, I replace BR3 with a new 2W02 2 amp bridge mounted about an inch off the board for better heat dissipation. I do this to all three bridges in this model, though BR3 is the main offender as far as heat damage goes.
If the old bridge burned the board/pads/traces too badly, I install a larger bridge screwed to the chassis and run wires to the necessary points on the PCB.
@@PsionicAudio awesome, so in case I have to go with an off board bridge I guess it would not hurt going with a bigger voltage rated one if it's still 2A? Thanks for the info!
If you go offboard increase voltage and current. Costs pennies and then you’ll never have to worry about it.
@@PsionicAudio got it, thanks for the guidance !
Are you sure that tube wasn't just resting on account of being knackered after a long squawk? 🙂
Can't moving resistors and capacitors around after they've been soldered cause weak or cracked solder joints?
Could. But I’m going back in that area when I change the jacks and a few other bits. So all will be well before it’s done.
Wish you were local to me, you’d get all of my amps for checkup.
Hi, person who owns this amp!
You have great taste in amps! 😁
But it's premium! By the way your discussion of PI cap leakage and what can happen goes a long way toward explaining how the 400v caps Mesa uses in this section are underrated for the job.
Turn the tube into a mini slide!
this is a highly overrated amp but still badass, i wouldn't mind having one
I've owned one like this for years! He just stood around in the corner:-(
I regret having bought it, it's a very boring amp. The preamp only works with full distortion. And the idea of 2 switchable power amps..can be nice..But doesn't do much. When I bought it in 1992, the seller said to me "Better buy the JCM 900 High Gain Dual Reverb. It's more versatile and just better". ...He was right ! I now have a JCM 900 High Gain Dual Reverb...and this is the best I've made!
Most forum warriors seem to think that the SLX and Mkiii is so much better than the Dual Reverb because of the diode clipping in it. Do you think it makes a notable difference since you’ve owned both models?
@@SoDawn3 Absolutely ! The Dual Reverb has completely different options! The SL-X is boring! Only high gain!
I never liked the jcm 900. Worst amp they made imo.
I'm not saying you're wrong for not liking the JCM900. But it's not the worst by far. JTM60 might hold that prize.
its likely that the one that you heard was out of spec. literally millions of guitar players are in line to " demand satisfaction " from your statement,,myself included
Oddly enough it's the only Marshall I've played so far that I liked. You have to play them really loud though.
Actually a JCM900 HGDR 100w combo with 2x12 Celestions I had back in the 90s was the best Marshall I've ever played.
@@PsionicAudio I'm with you 😉 My 6100H might be even worse.