Planning to mod my Valveking 112

TSE

New member
I want to do the "MESA" mod, the bass tightness mod so the bass rolls off at 700hz as poopsed to 300hz in it's stock form, and I want to remove the "class a/ab" knob and swap it with a noise gate by swapping R100 with a 1meg pot.

I'm pretty confident in the first two, but not sure about the last one. Which terminals of the pot do I wire to R100's lands on the board?
 
Re: Planning to mod my Valveking 112

My first response would be just buy a used Mesa.

be careful with doing any mods to a VK, it becomes an endless trap. For instance, after changing all the tubes, installing better OT/PT, doing various mods for more/less gain, swapping speakers, tighting up bass, swapping out cheap parts for quality parts, etc. you find yourself investing more oney trying to make the VK into something it's not.

It's like trying to soup up a Cavallier into a Honda.
 
Re: Planning to mod my Valveking 112

Are you enthused about learning to mod amps? Cuz this seems like a good case of "why don't you just buy the amp you really want rather than decrease the chances of selling your current amp".

But if you've heard that stuff all before and you know what you're doing, then I hope your mods go well.

The mesa one sounds like a good idea, after reading about it.
Do you need a noise gate? it sounds like the "regular" r100 mod is easier.
 
Re: Planning to mod my Valveking 112

Yes, I have modded amps before and like doing it:) I got my soldering skill because I work in electrical assembly. I like the Valveking tone already, I just like to tinker and make things preform to my specifications(mostly metal amp) so the Mesa mod and the other stuff would make the amp better for my needs.

The place where I got the info about the mods didn't really specify about the noise gate thing. He just said about the R100 mod that if you slam a 1meg pot in there it will be a noise gate like on the JSX. Not sure which lug gets soldered to what at the R100 reference destination.
 
Re: Planning to mod my Valveking 112

So, if you connect lugs 1 and 2 on the pot, and connect the spot that's the input of R100 to lug 3, and connect lug 2 to the output of R100, this will create a variable resistor (in place of the fixed value resistor of r100). I THINK...
the question then becomes which side is the input and which is the output of R100.

So I dunno, hopefully someone will tell me if I'm wrong.
 
Re: Planning to mod my Valveking 112

So, if you connect lugs 1 and 2 on the pot, and connect the spot that's the input of R100 to lug 3, and connect lug 2 to the output of R100, this will create a variable resistor (in place of the fixed value resistor of r100). I THINK...
the question then becomes which side is the input and which is the output of R100.

So I dunno, hopefully someone will tell me if I'm wrong.

Thanks for the help FuseG4. Would the test of you doods agree with that?
 
Re: Planning to mod my Valveking 112

Also, how much does capacitor voltage matter? Would it be a bad thing if I replace a .27uF 50V cap with a .47uF 100V? 500v? I think I can get most of the components from Radioshack, their cap voltages are higher.
 
Re: Planning to mod my Valveking 112

Higher voltage rating on the replacement caps is fine, at most it just means you're paying a bit more for a part better rated to stand up to harsh operating conditions than Peavey felt necessary. Avoid swaping in lower rated parts if possible. There's a risk of them not holding up for very long before burning out or exploding.
 
Re: Planning to mod my Valveking 112

it takes more than a few cap changes to make a mesa boogie.

Indeed, my goal is not to make a MESA or any amp. But to optimize the Valveking for metal tones exclusively, and the these mods seem like a good way to do it. I like to tinker, and having soldering skillz:yo: takes finding new tones to a different level for me. Just wanted a little help n' stuff, and this is a great place for that. Thanks:)
 
Re: Planning to mod my Valveking 112

you could put the bass caps in a dpdt toggle switch. once they are working, you can drill a hole in the face plate and have a kind of deep/tight switch.
 
Re: Planning to mod my Valveking 112

What are exactly the mods you want to do?

credit ilya-v)
MESA mod
It makes the gain channel million times better (exaggerating).
Mesa and Bogner like (Not exaggerating).

Remove R122 (no jumper needed).
Leave R124 in place (Don't touch it).
R116 to 10k (Wattage don't matter here).(10K has more gain, 22K has less... tightness of tone depends on EQ and setup)

The tone stack cap & resistor are crutial to Mesa sound;
C2 to 470pF
R4 to 47k

If it's too dark remove C149 (cut one leg of it).

The clean is unaffected.
You'll lose the low gain option (always high gain now, with less gain [10k]).
*But still can be very low or Very high gain.
The structure and articulation of the gain now is fenomenal .
The gain button now controlls C115 (470n) on/off, Soldano(off), Mesa/Bogner(on[tighter])
*If you liked the gain channel with a boost pedal, you'll "Die" from happiness on this mod. (it has plenty of gain now on the normal gain, and plenty & tighter gain on the
gain-on.

The Mesa mod removes the low gain mode completely.
And it lowers the high gain mode a bit and makes the sound much, much cleaner and defined but still with plenty of gain.

The gain switch now acts like a fat button.
What was the low gain (off) now has plenty of gain.
And what was with the gain boost on, now is a lot more
defined and clear.

(credit Stefan_L_01)
Just a note about the Mesa Mod: The higher the resistor value, the lower the gain. I tried once 39k and this almost disabled this stage, reducing it to the "normal" gain mode.
It´s logic, with a 100k or so you would have the cathodyan phase splitter with gain 1...

So if you want keep a noticable difference between the 3-stage gain and 4-stage gain, i´d use max. 10k. This already reduces gain a lot. You can compensate with a higher gain setting of the control, but again, the 2 gain channels get closer together.

If you need a low gain rock tone and a high gain mode ( cover band ), leave it the way it is, or increase it slowly and find the best setting for your style mix (2k, 4k, 10k, 20k).

credit ilya-v)
*Also made the Distortion channel tighter by changings the C103 from 2.2n to 1n.
made the bass roll off at 700hz (300hz old).

*Removed the A/AB class Pot. (Made the amp alot louder) no **** in the signal.

(Credit ilya-v)
About the R100 mod:

Remove the resistor and slam a 1M pot there.
What do you think the Noise Gate on the Peavey JSX is?


http://ultimate-guitar-valveking.wikispaces.com/Amp+Mods+-+Electronics
 
Re: Planning to mod my Valveking 112

^ it looks cool to me.
Do it, but record a demo before and after the mod to compare the results. Good luck.
 
Re: Planning to mod my Valveking 112

I can do this kind of thing and you're REALLY making me miss my old VK112...
 
Re: Planning to mod my Valveking 112

BLAST!! I have all the components except I'm not sure about these old caps I found to use for C2. Very uncommon and hard to find in town:/

For the MESA mod, I need to change the 270pF that's in the tone stack to 470pF. The caps I have say either RMC or RMO 470 10% on the front and Z5F on the back. I did a bit of research and the last number on caps can be a multiplier. So if this is true I have a 47pF cap, the numbering should say 471 to be 470pF.

BUT, I also read that on some of the older NOS/vintage caps they would just put the value in picofarads on the front and if it's like this then I should have a 470pF cap.

Confuddled...
 
Re: Planning to mod my Valveking 112

This is a cool thread. I love reading about amp mods. Good luck, and thanks for bringing all this information together here.
 
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