#1
Thought you guys might be interested to see these clips.

I've recently recapped my Marshalls, the JMP is a '71 and the JCM is a '81.
The replacement caps were all TADs.
I also did some minor mods, listed below.
The recordings were made with SM57 > MBox > MacBookPro > ProTools with no effects or processing.
The video follows a very rough step by step pictures of the work done.

The JMP has had the channels internally jumpered and has the LarMar type PPMIV. It's also had it's PT and switch replaced along the way, before I got it. I got a really nice deal on it because of that!!
The speaker here is a G12H and it's miked midway between centre and edge.
I was trying to keep it close to the original, classic crunch tones with less head mushing volume involved.
The MV is set to 3/4 here, and it's bearable in my bedroom/workshop/recording studio.
http://www.youtube.com/watch?v=wdfvC7xEm6s

The JCM800 is fitted with KT77s, has a resonance mod, some gain mods and a bootstrapped master volume. The MV is only set to 2/3 here and it maintains the low end much better than the standard 800 MV, does still loose some gain though.
The speaker here is a V30, again midway between centre and grill. The V30 really helped bring out the snarl of the 800.
I was going for that boosted 800 tone (but without a boost obviously!!), with some more pronounced lows and low mids, kinda like a Zack Wylde tone, as it fits with the band I'm in at the moment.
http://www.youtube.com/watch?v=gXKe_1K05uI

I'd be interested to hear what you guys think.
#3
Quote by WtrPlyr
I think the JMP sounded a little harsh, still nice though. Love the JCM800. You gave me GAS for one


Cheers, the 800 is my go to amp.
The JMP does a real nice job of cutting through in a band situation though.
#4
The 800 sounds great! I love it. The KT77's have a great low mid crunch.
I have a Peavey VTM right now, a JCM800 ripoff, I love it, but if I ever got my hands on a JCM800 2204, I'd want to give it KT77's. Mind sharing that particular mod?

The JMP had a hi-fi kind of sound that I normally associate with KT-88 modded Marshalls (here's a VTM with 6550's. Same kind of character, I think. http://www.youtube.com/watch?v=3K4s_esDuiw ), wasn't a big fan, but it sounds good.
Last edited by forsaknazrael at Dec 14, 2009,
#5
Quote by forsaknazrael
The 800 sounds great! I love it. The KT77's have a great low mid crunch.
I have a Peavey VTM right now, a JCM800 ripoff, I love it, but if I ever got my hands on a JCM800 2204, I'd want to give it KT77's. Mind sharing that particular mod?

The JMP had a hi-fi kind of sound that I normally associate with KT-88 modded Marshalls (here's a VTM with 6550's. Same kind of character, I think. http://www.youtube.com/watch?v=3K4s_esDuiw ), wasn't a big fan, but it sounds good.


Wouldn't really call the KT77s a mod.
They drop straight into the EL34 sockets, you just need to bias 'em up.
The depth mod has also added a real nice kick to the bass/low mid region.
I'd probably end up trimming some low end away to fit in a mix with a bass and kick drum though.

Thanks for the comment.
#7
this got me thinkin, how hard would it be to add on of those switches to switch from 100w to 50w like they had on the slash sig
Quote by gatechballer
SoLgEr is the ****ing man!!!!!
#8
Pentode/triode switch
Quote by envoykrawkwar7


edge11
that was an epic win
best thing ive read all day

[feel free to sig this statement]

Gear:
Esp Ltd Ninja 600
Esp Ltd F-50
les paul elite
5watt jcm800 clone
Roland jc-55
Crate V33
Jca20H
Ibanez tubescreamer ts9
Keeley ds-1
#9
Pentode/Triode switches are more for tonal differences.
The volume difference is not much.
Same applies to half power switches that "turn off" two of the valves.

If you want "the tone" @ lower volumes then you need to be looking at something like a THD HotPlate.
Crank the 800 master to 4/5 and have the THD set to -8dB is perfect for playing with an aggressive drummer.
Any lower settings on the THD or below 4 on the master is just loosing tone IMO.
#11
Quote by forsaknazrael
The 800 sounds great! I love it. The KT77's have a great low mid crunch.
I have a Peavey VTM right now, a JCM800 ripoff, I love it, but if I ever got my hands on a JCM800 2204, I'd want to give it KT77's. Mind sharing that particular mod?


i dont have a cab to play my VTM through but do you know any common mods for it?


7 String+ ERG Legion!!

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#12
Quote by SYLrules88
i dont have a cab to play my VTM through but do you know any common mods for it?

Yeah, I've done quite a bit of research.

The easiest and also among the most effective mods are:
- removing the bright cap (remove C2 from the control board)
- replace R2 with a higher value, maybe 220K (where I have it) or 330K. Should remove a lot of fizz. This is on the preamp board. It needs to be a 1W resistor.
- replaced R8 with 50k pot and 5k limiting resistor. Replace R9 with a 3K resistor. This will allow you to warm the bias of the VTM up a lot. The stock bias is at like 15mA or so, which is REALLY cold.
Last edited by forsaknazrael at Dec 18, 2009,
#13
Quote by SYLrules88
i dont have a cab to play my VTM through but do you know any common mods for it?


IMO, it's always best to start of with an idea of what you'd like to change as opposed to what mods are available.
Most things are achievable, more gain, more clarity/focus, more low end etc. etc. but I think it's important to have an idea of what you want first.

What sort of tones do you have in your head?


Never tried the re-amping via a separate power amp forsaknazrael.
Do you have any sound clips I can hear?