NAD - Marshall JCM 900 SLX 50

Bad.Seed

Well-known member
Man, the amps are really starting to stack up.

Picked up a whole JCM 900 SLX half stack for a great price last night. Pretty pumped to have this amp back in my hands, honestly. I sold it and my JCM 2000 DSL when I bought my Friedman JJ 2 years ago, and have missed them both ever since.

This one is in great shape, with only 2 minor bumps to the front, and no other damage to note. Master Volume A is scratchy but still easily usable. This one has quite a bit more gain than my last one, to the point I was actually quite surprised. This one also feels tighter. The owner just had the Power Transformer replaced, but seemed to have no knowledge of what was actually used, and all fresh tubes put in it.

Question on the Trannies: I know a lot of guys swear by big iron. Yet, a lot of guys say it's not necessary. I guess what I'm asking is, would it be worth it to put 800 style transformers in this thing? Would it make any difference? It's more of a curiosity question. Just wondering what the general consensus is.
 
ive never heard of anyone putting 800 transformers in a 900. not sure that would help your resale value either, i know if i was buying an SLX which i plan on doing id want a stock one
 
RaceU4her":22n57uv3 said:
ive never heard of anyone putting 800 transformers in a 900. not sure that would help your resale value either, i know if i was buying an SLX which i plan on doing id want a stock one
Totally understood. I'm not really concerned about resale, as I have pretty much nothing into it.

I recall reading a thread where someone has put 800 style trannies in a JCM 2000, which uses the same trannies as the 900, and noticed a marked improvement. But, it could jsut be internet BS.
 
I’d put a choke in the amp instead of whatever part/parts they sub in for a choke, put in a low end density/resonance pot and if you really want transformers spring for the Mercury Magnetics ones.
 
Nice find. As far as Iron, I am not sure how the 800 stuff compares the 900 stuff, but it is something that can turn a 'good' amp into a 'great' amp. As far as MM goes, I am honestly not sure if I am sold on them for the price gap with them and heyboer/ClassicTone, et AL. But that's your deal.
 
The iron I'd be looking at is the Classictone Upgraded 800 transformers. I will be adding a choke for sure, and a resonance mod is a must on the 900's, they tend to sound a little thin, although I've never played the MKIII model.

Again, the transformers are theoretical. I haven't even had a chance to turn the amp up since I bought it. Just thinking out loud and waiting for someone to tell me it's not worth it. I have $350 into the SLX, and it's already getting a tech visit. My tech is taking me under his wing and allowing me to watch and study his repairs, starting with this amp and the cap job on my 2204.
 
Brent Gutierrez did a great mod on an SLX I got from juggernaut. Loaned it to mailman,he loooved it. I think gsxrbusa has it now.
 
rottingcorpse":1rh4mtap said:
Brent Gutierrez did a great mod on an SLX I got from juggernaut. Loaned it to mailman,he loooved it. I think gsxrbusa has it now.

Any idea what was done?
 
So upon inspection, the amp has new caps on top of new tubes. I still haven't gotten to turn it up to see how it does, but I'm curious. I already know it has way more gain than my prior SLX, which is nice because I had to nearly max that one out to get good saturation.

I talked to my tech, and he said an Adjustable resonance control is easily possible. I may also install a choke as well. He's going to walk me through all these items and let me watch as he does the for me to gain a little experience.

Either way, I'm excited to have this amp!
 
When I had mine I also put in a larger value Bass pot (I forget what it was but I found it on the Marshall forum) and I ran it with real, NOS KT88s in it ( mine was a 50), I wanted to do the MM transformers but I ended up selling the amp...
 
PAULYC2":37mrgkwt said:
When I had mine I also put in a larger value Bass pot (I forget what it was but I found it on the Marshall forum) and I ran it with real, NOS KT88s in it ( mine was a 50), I wanted to do the MM transformers but I ended up selling the amp...

How did the kt88's sound? Too bright and HiFi or ok?
 
I liked them a lot, between the choke, depth pot, increased bass pot value, the last pair of caps before the Phase inverter were changed to Super Bass values and the KT88s the amp had great low end for chugging and I never found it bright, brittle and HIFI, and it seemed to gain some volume. But I like 6550s in a Marshall WAY more than EL34s so I may not be the one to ask. The MM transformers may have been too much (both money and probably not needed) but would have been a cool experiment.
 
Managed to get some time with the amp tonight and I'm seriously impressed. This thing sounds killer! I am going to guess that the tech that looked this thing over for the previous owner replaced some stuff and really got the amp running right. It sounds excellent. No lack of bass whatsoever, especially through the Friedman 412 cab. The amp has some great, aggressive high mids, but doesn't lack fullness at all. Hell, it even sounds fuller than my 2000 dsl 50 that's been modded and sounds killer.

Here's a clip I grabbed right before I ran out for the night. boosted 900 through the friedman cab, sm57 on the v30, e609 on the greenback

https://soundcloud.com/kyle-bull-760574723/jcm-900
 
Bad.Seed":1hvxgi4a said:
Managed to get some time with the amp tonight and I'm seriously impressed. This thing sounds killer! I am going to guess that the tech that looked this thing over for the previous owner replaced some stuff and really got the amp running right. It sounds excellent. No lack of bass whatsoever, especially through the Friedman 412 cab. The amp has some great, aggressive high mids, but doesn't lack fullness at all. Hell, it even sounds fuller than my 2000 dsl 50 that's been modded and sounds killer.

Here's a clip I grabbed right before I ran out for the night. boosted 900 through the friedman cab, sm57 on the v30, e609 on the greenback

https://soundcloud.com/kyle-bull-760574723/jcm-900

That sounds absolutely badass. Seriously great tone and I can tell that it cuts nicely.

Sounded better than I remember even. Maybe the cab is playing a role with that though.
 
swamptrashstompboxes":3fn3oisj said:
Bad.Seed":3fn3oisj said:
Managed to get some time with the amp tonight and I'm seriously impressed. This thing sounds killer! I am going to guess that the tech that looked this thing over for the previous owner replaced some stuff and really got the amp running right. It sounds excellent. No lack of bass whatsoever, especially through the Friedman 412 cab. The amp has some great, aggressive high mids, but doesn't lack fullness at all. Hell, it even sounds fuller than my 2000 dsl 50 that's been modded and sounds killer.

Here's a clip I grabbed right before I ran out for the night. boosted 900 through the friedman cab, sm57 on the v30, e609 on the greenback

https://soundcloud.com/kyle-bull-760574723/jcm-900

That sounds absolutely badass. Seriously great tone and I can tell that it cuts nicely.

Sounded better than I remember even. Maybe the cab is playing a role with that though.

It's quite possible. The Friedman cab actually has blown me away. It sounds absolutely massive without sounding too boomy or hollow. It really fills out the missing frequencies on all my marshall heads.

It's got me considering letting go of a couple other cabs I don't use as much to fund another be for the stable.

But anyways, yeah this 900 slx sounds quite a bit better than I remember my first one sounding. I'm very happy with it.
 
Bad.Seed":3489mpp4 said:
swamptrashstompboxes":3489mpp4 said:
Bad.Seed":3489mpp4 said:
Managed to get some time with the amp tonight and I'm seriously impressed. This thing sounds killer! I am going to guess that the tech that looked this thing over for the previous owner replaced some stuff and really got the amp running right. It sounds excellent. No lack of bass whatsoever, especially through the Friedman 412 cab. The amp has some great, aggressive high mids, but doesn't lack fullness at all. Hell, it even sounds fuller than my 2000 dsl 50 that's been modded and sounds killer.

Here's a clip I grabbed right before I ran out for the night. boosted 900 through the friedman cab, sm57 on the v30, e609 on the greenback

https://soundcloud.com/kyle-bull-760574723/jcm-900

That sounds absolutely badass. Seriously great tone and I can tell that it cuts nicely.

Sounded better than I remember even. Maybe the cab is playing a role with that though.

It's quite possible. The Friedman cab actually has blown me away. It sounds absolutely massive without sounding too boomy or hollow. It really fills out the missing frequencies on all my marshall heads.

It's got me considering letting go of a couple other cabs I don't use as much to fund another be for the stable.

But anyways, yeah this 900 slx sounds quite a bit better than I remember my first one sounding. I'm very happy with it.

I would be very happy with it too. The V30/GB combination is absolutely epic though, especially with mic placement being dead on.

I am scared to try a Friedman cab. Lol. I may never go back. Haha. I cannot justify what they fetch for as far as $$$ goes. I like picking up cabs loaded with British Celestions in them for $150.lol. I have nice cabs too, but I have not ever paid more than $400 for a mesa, avatar or orange cab.
 
I put Creambacks and V30s in an EVH 4x12 and it sounds awesome, but not as good as my Marshall 1960AHW with G12Hs.

BTW, the tone at 1:35 in that clip is what I'm talking about. Too much gain for me, but still great tone. I will grab one of these heads someday.
 
I had a Cali Mod Ceriatone 800 clone that had the original Ceriatone OT go out. I replaced both with Classictones, and the tone improved greatly. Way more Marshall 'kerrang' if you will....if you do a trans upgrade don't be afraid to save some cash and grab the Classictones over the MM...they sound killer.
 
swamptrashstompboxes":4oggn57s said:
Bad.Seed":4oggn57s said:
swamptrashstompboxes":4oggn57s said:
Bad.Seed":4oggn57s said:
Managed to get some time with the amp tonight and I'm seriously impressed. This thing sounds killer! I am going to guess that the tech that looked this thing over for the previous owner replaced some stuff and really got the amp running right. It sounds excellent. No lack of bass whatsoever, especially through the Friedman 412 cab. The amp has some great, aggressive high mids, but doesn't lack fullness at all. Hell, it even sounds fuller than my 2000 dsl 50 that's been modded and sounds killer.

Here's a clip I grabbed right before I ran out for the night. boosted 900 through the friedman cab, sm57 on the v30, e609 on the greenback

https://soundcloud.com/kyle-bull-760574723/jcm-900

That sounds absolutely badass. Seriously great tone and I can tell that it cuts nicely.

Sounded better than I remember even. Maybe the cab is playing a role with that though.

It's quite possible. The Friedman cab actually has blown me away. It sounds absolutely massive without sounding too boomy or hollow. It really fills out the missing frequencies on all my marshall heads.

It's got me considering letting go of a couple other cabs I don't use as much to fund another be for the stable.

But anyways, yeah this 900 slx sounds quite a bit better than I remember my first one sounding. I'm very happy with it.

I would be very happy with it too. The V30/GB combination is absolutely epic though, especially with mic placement being dead on.

I am scared to try a Friedman cab. Lol. I may never go back. Haha. I cannot justify what they fetch for as far as $$$ goes. I like picking up cabs loaded with British Celestions in them for $150.lol. I have nice cabs too, but I have not ever paid more than $400 for a mesa, avatar or orange cab.

I'm the same way. I've bought and flipped more than a few Peavey 412m, line 6 and Randall cabs loaded up with celestions. Within the last year, I've picked up a Diezel, Splawn, bogner and now Friedman 412, and they just seem to be on another level. They seem to be a good bit more full than the 1960, Peavey and even Mesa cabs (which I've never found to be boomy like the internet likes to say)

The Friedman fits the marshall style amps so we'll that I may just stick with it. Already ordered some bogner syle slide castor's for.kine. Cover is next for gigging as I'll definitely be bringing this cab with me for shows.

The slx sounds great though. The clip has a lot of gain and the dials have even more to go. Surprising really. I have a show in Canada at the end of them month and I'm debating bring the slx.
 
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