New Marshall JVM headshell...C83 mod info

* velcro-fly *

* velcro-fly *

Well-known member
Check these out....my buddy in Australia is building them. About a 500% improvement if you ask me. Between this and the "C83" mod I think I could almost get another one cheap and be able to live with it.

JVMHeadshell.jpg

JVMheadshell3.jpg

JVMheadshell5.jpg

JVMheadshell2.jpg


http://www.mccustomcabinets.com

Steve E
 
joshsage":1091f said:
BTW for folks like me not knowing what the hell is the C83 mod?
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From the guy that designed the amp:

"Removing C83 on the board will be the solution for what you are after. Just snap it off of the pcb and both gain and treble response are lowered while retaining the bite and not getting muddy. I also think that the gain control will be more usable in all its range and those modes more dynamic"

Clipping it will reduce the high end and have a usable gain range in OD1 & OD2 Orange and Red modes. Given range will be far more usable and the top end fizzle (prone to feedback) is gone

Response from longtime Gear Page lurker MRMOJORISIN, a high end gear owner that I've actually bought some stuff from and feel he know's whats up:

"Clipped mine this afternoon. The man wasn't lying. Eliminating a 5 cent cap from this amp took it from very good to great. It "feels" like an old Marshall now..."

and to answer "where the hell is C83 and is it marked" (from same lurker)

"Yes it is and its really easy to find. Front edge, left side of the board near where the input jack comes in. While you have chassis out, bias the damn amp right (about 42 ma). It will be an entirely different (better) beast after this 10 minute surgery."

FWIW - all the above is in a thread on TGP comparing a JVM to a Suhr Badger (pure genius :confused: ), I just cut and pasted the pertinent parts re: the mod.

Steve E
 
Riddick":762e3 said:
Does your buddy in Australia sell these head shells?
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Yeah man, it's his side business:

http://www.mccustomcabinets.com

The hardwood stuff is killer.

Brad is awesome, you couldn't ask for a better person to do business with. I don't know what the actual shipped cost is on them. I'll direct him to this thread, he can chime in and answer for you.

Steve E
 
Hey Brutha Steve ;)

Thanks for the compliments Sir!!!

It wasnt acually my idea to build the Plexi headshell for the JVM, it`s a customer request but i think it`s a big improvement on the original JVM headshell.
I`m also working on just making a replacement faceplate for this amp, i`m still experimenting with that idea tho. If you guys have any ideas or requests on the design i`d love to hear them.
I`m more than happy to ship these worldwide, PM me for details, just looking into a few different shipping options as we speak.

I`ve just done the C83 mod here just yesterday, came across it via a fellow gear head from Melbourne, it lowers the gain overall and also lowers the treble response, which is something that was irking me with the JVM. It is as simple as literally snipping the C83 resistor off alltogether, no soldering required at all. To my ears it gives the JVM a better overall voicing, instead of trying to dial out the upper mids it now seems to sound right.
There is still plenty of gain on tap, more than i need, but once again it`s a lot more useable. i would imagine with any such mod it`ll void warranty but well worth it IMO.

cheers
Brad
 
That looks absolutely amazing!!! :thumbsup:

Dave, to answer your question about the C83 snip and shrink wrap, i think It would definitely work.
 
Gainfreak":06d44 said:
That looks absolutely amazing!!! :thumbsup:

Dave, to answer your question about the C83 snip and shrink wrap, i think It would definitely work.
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I know jack diddly squat about amp mods....so this is just a general comment. I don't know where this cap is, (although I'm tempted to find out), but typicallly, leaving snipped components in a circuit is frowned upon, if for no other reason then it's a nice little antenna. It might be completely benign, or a big pain in the arse... Just somethhing to consider if you try it - and you find yourself picking up extra noise, don't immediately think the mod is no good - pull the cap entirely. Again - this would depend on where the cap actually is in the circuit. It'll be interesting to hear from people who do this mod....
 
Brad, what would the shipping damage be to the USA?

About this removal, I would de-solder one side first to make it easier to replace if I did not dig the mod. I dig the feel on od1 orange right now as it is, kind of boogie like feel.
 
SkyhighRocks":83327 said:
I really like the shell...I just don't really care for the Marshall logo that is on there. Looks too generic to me.
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I think the standard white / gold script logo would look cool.. No reason he couldn't do that as well.
 
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