Flying Pig

TWANG

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It takes a lot of guts for me to show the crazy parts and assembly of this Pignose amp.
Some parts are just way huger than they need to be.. all I had.
and chasing the tone problems down meant swapping in and out and in and out.
But man.. it's humongous! I retro thieved .. using Jim Marshall 1959 amp.:hmm:

Now I have to go back in, fix the sloppy wiring they did, get my components in
so they wont go bouncing out when it's playing.
And find something to replace that giant yellow cap!

:dude:
 

TWANG

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The wiring was just sucky. nothing twisted, too many wires bunched together.
goofy grounding.
but it looked factory to me.

I am tempted to remove that component board the one in the back, and just
make a bigger one. And shorten all those wires to the sockets.
and twist the heater wires better.
It likes to hum a song, but all I get is the Johnny Cash intro.. hmmmmmmmmmmm.
 

TWANG

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I dumped it for a greenie!
I have like six of those giants which I thought were smaller when I ordered them.

C9 on V1B.. R12 to 2K7. Well, 3K I didn't have a 2K7.

http://www.blueguitar.org/new/schem/misc_amp/pignose_g40v.gif

I copied Marshall

http://www.webphix.com/schematic heaven/www.schematicheaven.com/marshallamps/jcm800_superlead_100w_1959.pdf

values in several places.

It's a little screamer.. and the lows are huge now.. the mids not so strong, which is what the guy wanted.
I still think he's going to wrestle with the right speaker though, Lyle.
 

TWANG

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It's right off the Marshall schematic.
the original 10K was pretty hot to start with.
some recommended 4K7 and lower.
I settled on this but it IS a bit hot.
Even a 12AY7 breaks up pretty quick.
 

Lyle Caldwell

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Whoa, a 3K on the second gain stage and bypassed too? That would be hot even without the cap. I've gone as low as 2.7k with a 470pf-1n cap across the plate but with a bypass cap - zoinks.

It's all subjective, of course, but I found that to be an unpleasant distortion. There is often something to be said for alternating hot/cold bias on subsequent gain stages.
 

Lyle Caldwell

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You can also play around with a 10k partially bypassed in parallel with a cap and resistor in series. Lots of the "Jose" Marshall heads love variations on that. You can dial in pinch harmonics, for instance.

NOT trying to tell you what to do. Just shootin' the shit late at night.
 

TWANG

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I'll take all the shit you can shoot, Lyle!

I put a 10k in there just to compare it since I've had 8K, 4K7 and even 15K in there.
I was thinking of a switch on the cap as well.

I aint done messing with it.. I never am. So back to the bench and more fun.
 




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