Valveking 100 Mesa Mod

[rednax]

What does the Mesa mod do to the sound of an amp? From what I’ve read people use it with the preamp volume really low. Since I have a master volume, would it sound better since I can turn the preamp volume up?

[Enzo]

How about you tell us what the "Mesa Mod" might be, and we can look.

[rednax]

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

Apparently the low gain channel sounds like a soldano and high gain like a mesa

[loudthud]

I have a much more basic question. What's a Valveking and why would anybody want to mod one ? If there were two amps sitting side by side, could I tell which one has been modified ?

[Enzo]

Valve KIng is a popular Peavey amp. The "sounds like another brand" descriptions are usually remote at best.

I found the parts, took a while for R4 and C2. Those are in one of the tone stacks, lower left. R122 is a feedback resistor in a gain stage upper right. R116 is the cathode resistor of that stage.

[J M Fahey]

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

Apparently the low gain channel sounds like a soldano and high gain like a mesa

Beginning from the end, NONE of that.
Modifications described are minuscule and make as much effect as "replace the square mirror by a round one, lower windows half way, inflate tires to 10 psi less than Factory recommended and your Honda Civic will now become a Volkswagen Beetle"

1) V1b and V2A make a gain stage, with gain fixed to 100X thanks to R122/R123 220k/2k2 ratio.

Removing R122 makes stage open loop,so more gain, say 4X or 5X more.

But shorting R123 with Q103 does the same (kill NFB), so you are not getting anything you didnīt have before.

2) first time I see a "Mod" which states: "leave X part as before" (R124) ... why waste ink on what is NOT done?

3)

R116 to 10k

this un-Mods the previous Mod of replacing the cold cathode clipper mode by a regular bias one, which in dues time WAS a real Mod.
So switching back and forth 10 times between 2k2 and 10k might count as 10 Mods?
Again both values used a zillion times.

4)

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

Big blanket statement with not much substance to it.
C2 to 470pF makes a Fenderish treble control more of a Marshallish one.
Millions of amps with one or the other, that alone does not make them more or less "Mesa sounding".

R4 (bass slope) from 56k to 47k has even less influence, less than 20% variation, the classic Leo Fender "changes nothing" tolerance.

In fact associated C4 which is probably a cheap ceramic (simply because is not critical at all) will have worse tolerance than that, go figure.

In a nutshell and NOT dissing theP who asked in good faith:

5) MOST of those Guitar Forum "Mods" are suggested by non-Techs, in general change nothing or t least nothing as expected, but are considered VERY GOOD!!!! by those who suggest them (Builder Pride ahem!!!!)


6) most characteristics which define Boogie/Peavey/Fender/Marshall/etc "sound" come from the combination of 200-300 factors .... modding 2 or 3 WILL NOT TURN ONE INTO THE OTHER.

7) what many see as a certain Amp/Guitar/Pedal/whatsoever "sound" comes from MusiciansīFINGERS and there is no Mod to get that.

Consider this:

Exact same VOX AC30 was used by: Hank Marvin - Beatles - Stones - Status Quo - Queen.
Does ANY of them sound like the other?

Same Dual Showman Reverb with 15" JBL was used by Jerry Garcia - Dick Dale - Ted Nugent
Same thing.

Same Marshall Plexi or Mark2 (basically same thing) on 10 was used by Jimi Hendrix - Jimmy Page - Ritchie Blackmore - Ramones - Van Halen - Yngwie Malmsteen _ Angus Young - Eric Clapton - 10000 more, all different.

So tiny Mods are irrelevant in the great scheme of things.

If you put 2 heads side by side, modded and unmodded, same speakers, guitar and player and *quickly* switch back and forth , you will hear some change, no doubt.

But you leave amp in a rehearsal room one Saturday, during the week little Tech gremlins perform some Mod unknown to you, and you arrive next Saturday for rehearsal with friends, maybe you notice "something", not much, not sure what it is.

You will definitely NOT say "wow!!! Now my Peavey sounds like a Soldano .... Or a Mesa!!!!"

One extra example: a Peavey Butcher IS a JCM 800 on steroids, meets or surpasses the original any day of the week , and *some* users who listen with their ears and not their eyes have found so, simply by playing both side by side.

But 99% "listen" by looking at the magic script logo instead of the ugly angular one, also "listen" at the price label, and prefer the British import, go figure.

[glebert]

I just sold off my Valveking 212. I hadn't had one before and got it super cheap because it needed work, but I gotta say I was really impressed at how good the sounds were (and I am pretty sure it was not modded). My only real problem with it was how ridiculously loud the lead channel was, maybe it was modded after all

[rednax]

I'll probably just try it because it doesn't cost much and to find out if it actually makes a difference.

[35L6]

Let us know . Negative results are still data .