More Mods for my JCM800: New Grounding Scheme, Rework the Bright Cap Switch, Add a Switchable Clipping Circuit!!!

I took a couple of pics of what the chassis and its juicy bits looks like. Me thinks it looks cleaner. I also removed the earlier mod of adding that blue 1uF bypass cap across V2's 820ohm cathode resistor. Doing this also helped bring back the charm of the 2204's low input clean channel. The PT's centertap is grounded just to the left of the input jack. Output Jack is grounded to the 3rd ground point at the bottom of the chassis. And the PT's ground goes first to the cap and then to ground #5. Also got rid of the old massive dual cable that was connecting the effects loop board to the MV and treble pot, and replaced it with something sleeker:
New Ground Wiring Larry Style (2).JPG


A nice close up of the reworked bright cap. I love what I hear with the stock value 1000pF cap engaged... But it has to be loud for the magic to happen... REALLY LOUD!!! As an alternate cap value I'm digging this 360pF. I tried as low as a 250p, but settled on the 360p. I need to figure a simple way to secure the new fx-loop connecting cable... :unsure:
New Ground Wiring Larry Style (4).JPG
 
Today was the 3rd phase of mods that I wanted to introduce to this amp. I added a little pre-built circuit board that has two switchable mini-circuits, all in the name of Crunch and Distortion. The Mod Board, as it is called, is made by a Canadian who also makes some very interesting and killer amps. Welcome to V2 Amplification, and a big thanks to @Kerry Brown for letting me know about V2 Amps and the owner, John, who's a damn-good fellah... (y).

The board measures about 1" x 3", roughly:
80's Mod Board Install (1).JPG

And a link for some proper info on the Mod Board:
v2amplification.weebly.com

V2 Amplification - Amp Modules

Already own an amp but want to kick it up a little? Our Mod Boards can be added to existing amps to boost gain, fine-tune the low-end response, and put more tonal variations at your fingertips.
v2amplification.weebly.com

I had to drill a couple 1/4" holes, but all went well. And more importantly, it all works wonderful. A very cool mod indeed!
V2 Mod Board Installed (1).JPG

V2 Mod Board Installed (3).JPG


V2 Mod Board Installed (2).JPG
 
RVA said:
I imagine these amps get so personal at some point that it would be very difficult to part with them. Anyway, that is how I get about guitar creations
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Totally agree. This amp is an '82 JCM800 50 watt 2x12 combo, aka 4104, aka 2204. I bought this amp in '86 at a local Flea/Swap market for $200. The amp was in rough condition and needed some electronics works. Didn't know poop about maintaining an amp at the time. Fast forward to around 2005, and that's when the madness started. This amp has been my guinea pig for just about everything that has introduce me the world of modding. Which also opened the door to modding or building pedals, and modding or assembling guitars. This baby ain't going anywhere and it's my desert island amp... and I don't care if there ain't no electricity either...

and-thats-all-ive-got-to-say-about-that.jpg
 
--- wait wait wait -- I have a solid state Peavey that was BLOWN UP in a NUCLEAR accident -- and I BUILT a SH-iTTY wood cab for it -- and it works -- was THAT "maintenance"?
bandit 112.PNG

wow ----- the Jackson Lives with Robert in Californication----- the KUSTOM is long gone the MESA is left the realm of logic.........................still have the Hartke-- the strat and the dog toy! BUWAHAHAHHAHAHAHAH
 
syscokid said:
Today was the 3rd phase of mods that I wanted to introduce to this amp. I added a little pre-built circuit board that has two switchable mini-circuits, all in the name of Crunch and Distortion. The Mod Board, as it is called, is made by a Canadian who also makes some very interesting and killer amps. Welcome to V2 Amplification, and a big thanks to @Kerry Brown for letting me know about V2 Amps and the owner, John, who's a damn-good fellah... (y).

The board measures about 1" x 3", roughly:
View attachment 42585

And a link for some proper info on the Mod Board:
v2amplification.weebly.com

V2 Amplification - Amp Modules

Already own an amp but want to kick it up a little? Our Mod Boards can be added to existing amps to boost gain, fine-tune the low-end response, and put more tonal variations at your fingertips.
v2amplification.weebly.com

I had to drill a couple 1/4" holes, but all went well. And more importantly, it all works wonderful. A very cool mod indeed!
View attachment 42586

View attachment 42588


View attachment 42587
Click to expand...
Neat installation, well done. I'm kinda surprised that you didn't implement these mods yourself without purchasing the mod boards. The mods are derived from the standard "Josse" plexi mods, where the 2nd stage cathode is made similar to the first stage & a pre tone stack clipper is added (Josse used a master volume control rather than fixed resistors). The mods are easily tailored to ones personal tastes. Cheers
 
eSGEe said:
--- wait wait wait -- I have a solid state Peavey that was BLOWN UP in a NUCLEAR accident -- and I BUILT a SH-iTTY wood cab for it -- and it works -- was THAT "maintenance"?
View attachment 42593

wow ----- the Jackson Lives with Robert in Californication----- the KUSTOM is long gone the MESA is left the realm of logic.........................still have the Hartke-- the strat and the dog toy! BUWAHAHAHHAHAHAHAH
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You let go of the Mesa?
 
ivan H said:
Neat installation, well done. I'm kinda surprised that you didn't implement these mods yourself without purchasing the mod boards. The mods are derived from the standard "Josse" plexi mods, where the 2nd stage cathode is made similar to the first stage & a pre tone stack clipper is added (Josse used a master volume control rather than fixed resistors). The mods are easily tailored to ones personal tastes. Cheers
Click to expand...
Ha ha... Don't be surprised. After I was lead to the V2 website to check out the V2 amps, I noticed those cool mod boards that John from V2 was offering. I contacted him for more info, and he was more than willing to exchange any info. John does this stuff on the side, and seemed like a true amp nerd. So a little bit over a year ago I bought two of his Mod Boards. It looked like a very clean and easy way to apply and switch my two JCM800's into obnoxious amounts of gain when I'm in the mood. I had no idea that these circuits were related to the late Jose Arredondo's bag of tricks. When I tried to look at and understand the Jose mods, it was over my head and it seemed to be too risky for me to attempt.

And if you go to the V2 website, you'll notice that John likes to use those toroidal style transformers for the PT. I don't know anything about them, but they look like donuts. I think I want an amplifier with a donut for a power transformer... :giggle:
 
The boards definitely make for a neat installation & would make it easy for anyone unsure of the workings of these type mods.
Toroidal power transformers do have a few advantages over conventional types. As well as low profile, they radiate less of a magnetic field. The magnetic field is concentrated in the center of the toroid, making them more efficient. I have used a toroidal PT on a small (10 watt) homebuilt amp in the past. Cheers
 
syscokid said:
Today was the 3rd phase of mods that I wanted to introduce to this amp. I added a little pre-built circuit board that has two switchable mini-circuits, all in the name of Crunch and Distortion. The Mod Board, as it is called, is made by a Canadian who also makes some very interesting and killer amps. Welcome to V2 Amplification, and a big thanks to @Kerry Brown for letting me know about V2 Amps and the owner, John, who's a damn-good fellah... (y).

The board measures about 1" x 3", roughly:
View attachment 42585

And a link for some proper info on the Mod Board:
v2amplification.weebly.com

V2 Amplification - Amp Modules

Already own an amp but want to kick it up a little? Our Mod Boards can be added to existing amps to boost gain, fine-tune the low-end response, and put more tonal variations at your fingertips.
v2amplification.weebly.com

I had to drill a couple 1/4" holes, but all went well. And more importantly, it all works wonderful. A very cool mod indeed!
View attachment 42586

View attachment 42588


View attachment 42587
Click to expand...
John is also on the Canadian Guitar forum. He lives about an hour and a half from me. He invited another forum member and me over to try his amps. I was very impressed.
 
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Kerry Brown said:
John is also on the Canadian Guitar forum. He loves about an hour and a half from me. He invited another forum member and me over to try his amps. I was very impressed.
Click to expand...
John also seems to have some kind of connection with Phaez Amps, too.

And yet in another interesting development that I got wind of yesterday...: I think John (V2 Amps) is testing the waters for offering an amp kit based on his Caldera amp design. I sent John a message, asking him for more info. Haven't heard back yet. I certainly don't need more amps, but this is too interesting to pass up, ha ha... :BH:
 
Just confirmed that John McDonald of V2 Amps is going to round-up all the parts needed for one of his V2 Caldera kit's. John and his V2 Amps are out of Canada... Vancouver area? I forget who makes the toroidal power tranny for him, but he gave me a choice on the OT: Hammond or ClassicTone. I'm very happy with ClassicTone trannies, but I went with the Hammond to keep the Canadian connection intact! The toroidal PT is definitely a custom order for John, and depending on the logistics effects of the current crudyvirus, nobody's sure about how soon the special PT is going to arrive.

Anyways... I'm looking forward to this. New thread coming I suppose... :giggle::flash::giggle:
 
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