JCM 900 MKIII & SL-X + Hot Mod V2 (Clips Added)

[marshallmellowed]

Just curious how many own a MKIII and their thoughts. Picked up a 2500 50w MKIII, as I've been curious about the single channel with the diode clipping for a while now. May end up trying it and flipping it, but one just never knows until they spend some time with an amp. I've got a 2500 50w SL-X that I'm curious to A/B it with. The circuits are very similar, aside from the diode clipping in place of the SL-X added tube stages. I'm planning on trying a Hot Mod V2 in the MKIII, which should be an interesting comparison, an MKIII with a Hot Mod vs. a stock SL-X.

 

[LPMarshall hack]

I have a MKIII 2500, from 1990. I have NOS RFTs in it. I love it. I use it like this:

Pre amp: 8-10
Gain Sensitivity: 0

I keep the Gain Sens off because I don’t really like all that gain. Sounds too fuzzy to me if you crank that knob too high.

I dont use the FX loop, so I put a patch cord in it and adjust the mix knob to about 11 o’clock. This adds a noticeable boost. I don’t know why it does from a technical standpoint, but maybe someone else does and can chime in.

I generally run an SD-1 in front set to clean boost.

It’s a beast of an amp and I’ll probably never part with it.

I think a Hot Mod would sound great with it and I’d love to try one…maybe someday.

I have no experience with an SL-X.

Hope that helps.

 

[LPMarshall hack]

Heres a couple of videos comparing the two amps (and also a Dual Reverb).

 

[marshallmellowed]

I have a MKIII 2500, from 1990. I have NOS RFTs in it. I love it. I use it like this:

Pre amp: 8-10
Gain Sensitivity: 0

I keep the Gain Sens off because I don’t really like all that gain. Sounds too fuzzy to me if you crank that knob too high.

I dont use the FX loop, so I put a patch cord in it and adjust the mix knob to about 11 o’clock. This adds a noticeable boost. I don’t know why it does from a technical standpoint, but maybe someone else does and can chime in.

I generally run an SD-1 in front set to clean boost.

It’s a beast of an amp and I’ll probably never part with it.

I think a Hot Mod would sound great with it and I’d love to try one…maybe someday.

I have no experience with an SL-X.

Hope that helps.

Alright, got one user, thanks. From what I've read, and looking at the schematic, the Sensitivity control brings in the clipping diodes. With that control at zero, the diodes have little to no affect, which is kinda cool in a way.

 

[marshallmellowed]

Heres a couple of videos comparing the two amps (and also a Dual Reverb).

Funny, I watched all those videos before buying the amp, pretty informative. I had decided against the Dual Reverb, as I'm not crazy about the design, mostly op-amps. The MKIII (non-reverb) and SL-X both caught my interest.

 

[LPMarshall hack]

Alright, got one user, thanks. From what I've read, and looking at the schematic, the Sensitivity control brings in the clipping diodes. With that control on zero, the diodes have little to no affect, which is kinda cool in a way.

Yes, the Gain Sensitivity knob brings in the diodes. With it on zero, the diodes are bypassed. This supposedly makes it identical to a JCM800, according to some experts. But I also have no experience with an 800 so I can’t confirm.

I’d be interested in your thoughts on the differences between your two amps.

 

[LPMarshall hack]

I played in a band with a guy who played a DR. It sounded awesome as well. I’d have no problem playing one of those.

 

[V-man]

Unfortunately, you cannot use a hotmods on a JCM 900. However Armored Amps offers an additional preamp tube at the input stage that requires replacing the jack.

 

[blue]

I have a MkIII 2500. I must admit, I haven't used it for 2 or 3 years! I had the same thought as you though, trying the hot mod in it to make it a sort of SL-X. I have checked the Legendary Tones website and the Mark III is listed as being compatible.

 

[marshallmellowed]

I have a MkIII 2500. I must admit, I haven't used it for 2 or 3 years! I had the same thought as you though, trying the hot mod in it to make it a sort of SL-X. I have checked the Legendary Tones website and the Mark III is listed as being compatible.

Yes, the "Standard Wiring" version is compatible. David (Legendary Tones) had mentioned that his 1st customer was a MKIII owner.

 

[Mitchell Pearrow]

I have zero experience with either the
SLX
or the MK lll
But I have had good times with a DR 50 watt

 

[paul-e-mann]

Ive played all 3 900's a little and liked them all but didn't play them enough to say I liked one better than the others. I thought I'd like to get one some day but I dont know which one to get.

 

[marshallmellowed]

Ive played all 3 900's a little and liked them all but didn't play them enough to say I liked one better than the others. I thought I'd like to get one some day but I dont know which one to get.

It's been years since I played through one of the 900's with the clipping diode circuit, so it'll sort of be like the first time for me, as I really don't remember. I remember having a JCM 800 2205 with the clipping diodes several years back and thought it was too thin sounding. Also had a 2555SL, which uses a clipping diode circuit in the "Rhythm Clip" mode. My main interest is in installing the Hot Mod V2 for more tube gain, and using the diode circuit minimally, just to add some variation. The same Hot Mod V2 (Standard Wiring) will work in my SL-X, which David (Legendary Tones) thinks should be similar in gain to a 5150.

 

[Deftone]

Congrats! Nice score!

I have an SL-X 2500 and a DR 4500. I love them both. Always wanted to try an MKIII.

 

[marshalled]

I have both amps ...different beast I don't need necessary mod the mk3.

Is important with mk3 up the volume... Not necessary with sl-x my 2 cents...

 

[mrjones2004x]

I’ve got the 2501 combo. Rehoused in a 2x12 vertical combo setup.
Mine is modded.
D1, D2, ZD1, ZD2 & C1 disconnected. NFB parallel 4.7k.
Fx loop is used for tc nova system and the pot set on max. Lower settings sound weak?
I play with the sensitive from half way to max usually and the preamp from half to three quarters up. Sometimes both are dimed. It never gets buzzy or sounds like distortion pedal sounds.
Mine seems to differ from everyone else’s experience as if I turn off my sensitivity knob it’s very thin sounding and really bright (not sure if gets thicker when played loud to be honest). My sensitivity knob is basically working like a body or resonance knob now. It adds gain still but really beefs up the sound.

Can’t comment on a stock one as I got it already modified. I love mine. I don’t have loads of gear and I flip guitars no end but this amp has been with me 5 plus years and I’d never sell it

 

[marshallmellowed]

I have both amps ...different beast I don't need necessary mod the mk3.

Is important with mk3 up the volume... Not necessary with sl-x my 2 cents...

Just FYI, but the "Hot Mod V2" is a plug-in module that adds a preamp tube, increasing the amount of gain on tap, there are no changes made to the amp internally. Pretty cool, actually.

 

[MKIII900]

I

Just curious how many own a MKIII and their thoughts. Picked up a 2500 50w MKIII, as I've been curious about the single channel with the diode clipping for a while now. May end up trying it and flipping it, but one just never knows until they spend some time with an amp. I've got a 2500 50w SL-X that I'm curious to A/B it with. The circuits are very similar, aside from the diode clipping in place of the SL-X added tube stages. I'm planning on trying a Hot Mod V2 in the MKIII, which should be an interesting comparison, an MKIII with a Hot Mod vs. a stock SL-X.

I Have a MKIII 2501 combo and I really like it. I was considering trying the hot mod out at one point, but after a bit of tweaking I found the sweet spot with the amp and I can go from clean to as mean as I generally need to be with the volume on my guitars. Even with the diodes dialed in a bit, it cleans up really nice for a Marshall. The presence control on mine really helps with heavier tones. Crank it way up and it starts to chug with the preamp dimed, and sensitivity up over half.
It can't do them all at once but it's a great amp for a lot of different styles. I really like the built in dual master volumes. The FX loop is a must for me. That's why I'm not using a single channel 800 from roughly the same era.
The combo format of the 900's is also really compact for a 50 watt tube amp. I like having a relatively tiny amp that can crank out such a big sound.

I'd love to hear yours with the hot mod if you have the chance to record and post clips in the future.

 

[marshallmellowed]

I

I Have a MKIII 2501 combo and I really like it. I was considering trying the hot mod out at one point, but after a bit of tweaking I found the sweet spot with the amp and I can go from clean to as mean as I generally need to be with the volume on my guitars. Even with the diodes dialed in a bit, it cleans up really nice for a Marshall. The presence control on mine really helps with heavier tones. Crank it way up and it starts to chug with the preamp dimed, and sensitivity up over half.
It can't do them all at once but it's a great amp for a lot of different styles. I really like the built in dial master volumes. The FX loop is a must for me. That's why I'm not using a single channel 800 from roughly the same era.
The combo format of the 900's is also really compact for a 50 watt tube amp. I like having a relatively tiny amp that can crank out such a big sound.

I'd love to hear yours with the hot mod if you have the chance to record and post clips in the future.

Yeah, I was buying another Hot Mod V2 anyway, as there are 2 wiring versions, and the one I have only works in my Reissue amps. It currently lives happily in my 2203x. I've got some earlier Marshall's that that require the other Hot Mod V2 wiring configuration, so it'll be trying it in some of those amps also. Can't promise anything, but I'll try and post some clips of the MKIII with the Hot Mod V2.

 

[marshallmellowed]

Changed the thread title, as my most recent interest is how these amps sound stock, and also with the Hot Mod V2 EVO installed. Just finished trying the HMV2 in the SL-X and was really impressed with what it does for the amp. Prior to installing the HMV2, the amp was a bit more compressed and not as open sounding as my 2203x. With the HMV2 installed the amp has taken on a new character, much closer to the 2203x. The MKIII 2500 is my next experiment with the HMV2, hope it sounds as good, or who knows, maybe better.