Hot Switch Mod In My Plexi 50

[shortfuse]

I added the hot switch mod to my Hoffman Plexi 50 this weekend and wow it is a whole different amp.  I wired it up full time with no switch and I think it sounds better than my 2204 now.  But I will miss being able to blend the hi and low channels of the clean sound of the stock plexi pre amp.  So it's study time on Sluckeys dual pre amp layout.  I think I am going to try and marry the 2 together in one amp.
This is the 1st thing I have accomplished without messing something up.  Everything wired up correctly and worked the 1st time.  Even though the mod layout  http://www.el34world.com/projects/hotswitch.htm does not show it, I figured out the wiper of the new MV (which is labeled 8) went to V3 pin 2 because it shows it in the wiring diagram  http://www.el34world.com/projects/images/Plexi50HotSwitch.gif.  Which you think would be obvious because the wiper of the treble went there before.  I must admit, I did think of leaving the wiper of the treble hooked up to V3 pin 2 and just adding the master wire to it but it just did not look right.

[Madison]

What good timing.
I am just about to wiring mine up.
Is yours quiet?
Is there any chance, any chance at all, you could share a picture of the guts?
If not, that's cool.

I'm not worried about myself wiring it properly.
What I am super paranoid about which lines get shielded to keep it quiet.

[Tone Junkie]

Im with you Madison i like to shield any long run, I dont want any stray noise getting in.
Bill

[shortfuse]

Madison no problem.  I will pull the chassis again tonight and take a shot for you.  For the most part it is pretty quiet.  No more noisier than my stock 2204, or 76 JMP SL.   

[Madison]

That would be awesome!
Thanks for taking the time.

[EL34]

The hot switch mod is not noisy.
I guess you could make it noisy if you had horrible wiring skills.

The mod jacks up the tone becaus it pushes a stronger signal through the tone stack.
The amp seems to have more of everything.

The cool thing is that by adjusting the two controls, volume and master, you can get just about any combo you like.

Maybe not death metal, but you can get some heavy tones and some very nice clean tones

[Madison]

I had it hooked up on another build for a brief time, just to check it out, and loved it.

I am assuming I would just shield the input all the grids?
I am working with a pretty small chassis.

Thanks.

[topbrent]

The hot switch mod is not noisy.
I guess you could make it noisy if you had horrible wiring skills.

The mod jacks up the tone becaus it pushes a stronger signal through the tone stack.
The amp seems to have more of everything.

The cool thing is that by adjusting the two controls, volume and master, you can get just about any combo you like.

Maybe not death metal, but you can get some heavy tones and some very nice clean tones

Doug, 

A question that I have had for a while is about the general difference in tone between a Hotswitch Plexi vs. a 2203-JCM800 arrangement with the treble peaking stuff?

[shortfuse]

Here's the pic's.  I put one in of the stock 4 input wiring also.  The only thing I think I would do different is put a ground bus wire along the back sides of the pots and not daisy chain them.  But it works fine as is.  I am also running this with KT88's.

[EL34]

A question that I have had for a while is about the general difference in tone between a Hotswitch Plexi vs. a 2203-JCM800 arrangement with the treble peaking stuff

Not sure what this means

[shortfuse]

A question that I have had for a while is about the general difference in tone between a Hotswitch Plexi vs. a 2203-JCM800 arrangement with the treble peaking stuff

Not sure what this means

Topbrent
I think I know what you are asking as I have a 1976 JMP 2203 also.  The plexi with the hot mod has a much deeper and richer tone that the 2203 in my opinion.  I have the treble set at about 7 and the Bass at 6-7 on the plexi with the hot mod and my stock 2203 the treble is usually never past 4 or 5 and the Bass is at 10 all the time.  I also have one of Doug's original iron box 50's I picked up a few months ago (great amp I should post pic's it is like new condition).  This one has a switch to flip the hot mod on or off where the bright switch would have gone and again I found this amp to be much deeper tonally than my 2204 but not as deep as the Plexi 50 with the mod.  I wired the hot mod permanent on the Plexi 50 as I don't see the need to flip it on or off.  As Doug has stated in the past once you try it the switch will be left in the on position anyways.
Hopefully that sorta answers your question.  

[jerrydyer]

2 additional capacitors and one resistor change. 2203 2204 that is . Doug puts his cool mod up for free. Another dude is charging 500 bucks to do his "Van Halen mod"

add a PPIMV to youll be screaming