NAD JCM 800 RI

[Erock]

Except for the caps, I think the reissue 800's are made better than the old ones. The wiring is neater, the boards are made closer to spec thanks to modern technology. Great amps!

Look at that PCB... seems almost transparent
Modern Marshalls are notorious for their cheap boards
If I had to get one of those modded, I'd have it completely rewired PTP
Everybody should have an 808

Damn, didn't notice that before, but you're right! It does look transparent, lol.
Oddly it doesn't feel as flimsy as a lot of boards I've looked at, it doesn't flex or anything, and no sockets or pots/jacks are wired directly to it. I've heard the same rumors for years though. That actually would be a fun project however, it looks very simple to trace this circuit, and all the values are easily visible.

Stumbled upon this:

http://www.harmonycentral.com/forum/forum/guitar/acapella-28/1599519-

Looks pretty cool. Obviously this is a long term project. The PCB is not going to crack if you leave the amp at home or in the studio.

Holy cow, that looks friggin awesome! Thanks for the link!

 

[Shiny_Surface]

Damn, didn't notice that before, but you're right! It does look transparent, lol.
Oddly it doesn't feel as flimsy as a lot of boards I've looked at, it doesn't flex or anything, and no sockets or pots/jacks are wired directly to it.

Nothing wrong with the reissue pcb imo. All the interactive components are chassis mounted so the pcb is isolated if you will as you stated.

The Dagnall transformers on the reissues are made in Malta/different factory and that was the reason I chased originals because I wanted to compare the old iron.

SLO pcb looks kind of transparent too, it's just the color of the material they chose.

 

[Erock]

Damn, didn't notice that before, but you're right! It does look transparent, lol.
Oddly it doesn't feel as flimsy as a lot of boards I've looked at, it doesn't flex or anything, and no sockets or pots/jacks are wired directly to it.

Nothing wrong with the reissue pcb imo. All the interactive components are chassis mounted so the pcb is isolated if you will as you stated.

The Dagnall transformers on the reissues are made in Malta/different factory and that was the reason I chased originals because I wanted to compare the old iron.

SLO pcb looks kind of transparent too, it's just the color of the material they chose.

Yeah, I'm not real concerned about it, I would be more worried about the little fx loop board tbh, it looks thinner than the main pcb. That would be a sick project though, did you see thst RI?

So after comparing iron, what was your opinion?

sounds nice, i like both clips.
nothing wrong with a boosted marshall, especially a 2203.
you dont really need to do anything other than add a boost, doesnt need modded unless you have a certain sound you want.

Thanks Tom, you've been telling me that for years haven't you, lol. I'm really impressed by this thing.

 

[Kapo_Polenton]

I gutted my LAney Pro tube and put in a PTP 2204 circuit... my advice is that if it isn't broken, don't fix it. Reason being, unless you are good with soldering and making everything look tidy, when you go to sell it, even though the PTP is an upgrade, someone will look at the work and think it isn't pro (even though old amps looked like rat's nests). I do like the ease of tweaking but ultimately i put the circuit back to more or less stock :-/ ..

 

[Erock]

I gutted my LAney Pro tube and put in a PTP 2204 circuit... my advice is that if it isn't broken, don't fix it. Reason being, unless you are good with soldering and making everything look tidy, when you go to sell it, even though the PTP is an upgrade, someone will look at the work and think it isn't pro (even though old amps looked like rat's nests). I do like the ease of tweaking but ultimately i put the circuit back to more or less stock :-/ ..

I'll be honest, it would take some serious problems for me to gut this amp, it sounds pretty killer the way it is.

Also you're right, i consider my work neat, but I don't do it for a living. The idea of wiring the whole circuit onto a board looks awesome, but would be a ton of work and time. I'm much better off working on my chops I think, lol.

 

[Erock]

Damn, didn't notice that before, but you're right! It does look transparent, lol.
Oddly it doesn't feel as flimsy as a lot of boards I've looked at, it doesn't flex or anything, and no sockets or pots/jacks are wired directly to it.

Nothing wrong with the reissue pcb imo. All the interactive components are chassis mounted so the pcb is isolated if you will as you stated.

The Dagnall transformers on the reissues are made in Malta/different factory and that was the reason I chased originals because I wanted to compare the old iron.

SLO pcb looks kind of transparent too, it's just the color of the material they chose.

Hi Tom, I gotta stop bumping my thread, but I have to pick your brain on transformers. I know we have similar tastes. Thanks man!

Eric

Edit: meant to be a PM, lol

 

[lespaul6]

there isn't a thing wrong with that pcb... marshall has been using that ST 1 board since the 70's and they are bullet proof. You can see through a Soldano pcb as well.. has nothing to do with the durability or the tone. In fact, my tech here locally said that the newer ST 1's are actually an improvement over the old "dog ear" boards they used in the 70's....had to do with the traces/pathways.

 

[Shiny_Surface]

Hi Tom, I gotta stop bumping my thread, but I have to pick your brain on transformers. I know we have similar tastes. Thanks man!

Eric

Thanks Eric I'm not an authority on transformers by any means , the original ones i played sounded different and overall warmer on average but that could have been due to other variables in the circuit/system in whole or part other than just the transformers.

A co-worker who builds amps on the side told me that just being old makes the transformers sound different. So if you went back in time and put reissue transformers in the manufacturing who knows how close they would sound to the originals now lol.

If it sounds good stick with it I say these days...

 

[JTyson]

That chandler is pushing that thing nicely
I know their mic pre's are pretty dam good, I figured that boost box would be a good race test candidate.
I would not worry about the paper thin pcb ( ), they have only logged more hours on the road than any amp ever made
I have several Marshalls with those same boards that are 30+ years old that have been rode hard and put up wet a thousand times with no board issue's whatsoever
Nice playing Eric

 

[Erock]

That chandler is pushing that thing nicely
I know their mic pre's are pretty dam good, I figured that boost box would be a good race test candidate.
I would not worry about the paper thin pcb ( ), they have only logged more hours on the road than any amp ever made
I have several Marshalls with those same boards that are 30+ years old that have been rode hard and put up wet a thousand times with no board issue's whatsoever
Nice playing Eric

Thanks man, appreciate that. The chandler is a blast, it's my favorite for the rock and hard rock tones. Also a sweet solo boost on the extreme setting. It just sweetens up the lows and highs while boosting, and keeps the bottom deep and thick. It's also got settings to take it from a clean boost to almost a fuzz, so it's like 5 boxes in one. Pricey little bugger though. I got a trial period and fell in love with it, otherwise I might not have ever gambled on it.

 

[Loudness250]

I had jcm800 2203 RI and I've also had a 2204 made in 86', I could swear the older 50w was louder than the RI 100w. It just didn't seem very loud. Was it the caps? I recapped it with f&t's and it didn't change at all. It sounded great but seemed like it should have been way more of a beast.

 

[Anonymous]

I've been looking for a beater jcm to send to FJA for some mods, and saw this 2003 RI in craigslist for a really good price. It's in surprisingly clean shape, just had some dirt and stickers on it. It was stuck in pawn when I got it, lol, so she's been around the block. The guts look really clean though, and she sounds great after a little TLC. I'm kind of surprised how well it's built, I thought the reissue would be made cheap, but it looks great. I'm really liking it, raw aggressive marshall tone. I didn't buy it for metal, but I can't imagine there is much ground these amps can't cover with a boost.

I did notice a couple issues with it. A couple caps were bulging, and it looks like someone added a half power switch. Other than that, it appears stock. I didn't think I would see caps bulging in a 10 yr old amp, but it's hard to miss. It still sounded ok, but I replaced them with F&T just to be on the safe side. So far, I really like the results. It's not a huge difference, but definitely better bass response and quieter at idle. Anyway, here are some pics.

Here are a couple quick clips

Splawn v30 x creamback 65

Updated added Mills acoustics j75 x v30

those sound REALLY good. when i click to get them to the youtube page though, they wont open. i like to keep the youtube vids open while i browse other threads. neither were listed on youtube though...

 

[Erock]

I had jcm800 2203 RI and I've also had a 2204 made in 86', I could swear the older 50w was louder than the RI 100w. It just didn't seem very loud. Was it the caps? I recapped it with f&t's and it didn't change at all. It sounded great but seemed like it should have been way more of a beast.

wow man, not sure, but that doesn't seem right. It should at least be perceived as being as loud as the 50W I would think. This amp will peel paint off the walls, it literally makes my teeth hurt when I get the master cooking. I can feel the hearing loss trying to get the goods out of the powersection with this thing.

Here are a couple quick clips

Splawn v30 x creamback 65

Updated added Mills acoustics j75 x v30

those sound REALLY good. when i click to get them to the youtube page though, they wont open. i like to keep the youtube vids open while i browse other threads. neither were listed on youtube though...

thanks man, glad you liked them. I had them set to unlisted, but I've changed them both over to public, so hopefully that helps.

 

[born_hard]

I really like my Reissue JCM800 too. I replaced the power tubes with brown based Tesla El34 and now it sounds awesome.
I boost it with a Koko boost for some tighter heavier rhythm and for leads and the amp sounds very good. The overtones, the feel, its all there.
What i´m questioning, would the sound benefit by a Transformer and choke Change ? Has somebody tried it already?
Or is it not necessery?
I m lusting for this set:
http://www.classictone.net/Marshall-100 ... rmers.html

here is another actual thread with the same topic
viewtopic.php?f=3&t=155193

And what is this guy talking about the coupling caps in post 53?
https://www.thegearpage.net/board/showth ... 979&page=4

 

[Erock]

I don't know man, judging from what people are saying, it could be hit or miss. I'm not sure I would want it any brighter than it already is either. That clip from the thread did sound like quite an improvement though. It would be fun to try what glip suggested in that other thread, unsolder the original and just clip in one tap from the new transformer to hear it. I really liked what it did to the haze, but who knows the results with a jcm. I thought the stock transformers on the RI were supposed to be decent anyway, have you read/heard otherwise?

 

[Schaf]

I don't know man, judging from what people are saying, it could be hit or miss. I'm not sure I would want it any brighter than it already is either. That clip from the thread did sound like quite an improvement though. It would be fun to try what glip suggested in that other thread, unsolder the original and just clip in one tap from the new transformer to hear it. I really liked what it did to the haze, but who knows the results with a jcm. I thought the stock transformers on the RI were supposed to be decent anyway, have you read/heard otherwise?

I would't change it unless something's wrong with it. I doubt it'll sound "that" much better if any at all.

 

[Anonymous]

And what is this guy talking about the coupling caps in post 53?
https://www.thegearpage.net/board/showth ... 979&page=4[/quote]

coupling caps are usually between each gain stage, and among other things, they generally determine how much bass at a certain frequency gets through to the next stage. (this is a REALLY simple simplification just to answer your question)

the PI caps he's referring to are the final coupling caps in the preamp stage, each coupling cap coming off one side of the PI tube, and feeds each capacitors (or coupling caps) set of power tubes in typical 100watt guitar amp (or in a 50 watt, one power tube each).

usually, by raising, or lowering the value of the coupling caps, especially the PI caps, you can change the overall bass response of the amp....lower being brighter, and higher lets more bass through, so it sounds darker.

if you're REALLY interested in thinking that through, and learning a bit about guitar amps, you can check out this peavey 5150 signal flow diagram:



in that diagram on pages 1 and 2 c6, c2, c1, c57, c56, c58 are the interstage coupling caps.

on page 4 C29 and C28 are the PI coupling caps that feed each pair of output tubes.

raising these to .1 (or 100nf) as opposed to the stock .047 (or 47nf) would increase bass significantly

lowering them to .022 or 22nf would cut some bass.

 

[WizardSouth-JP]

run this thing into 2 Mills - just for fun try it