Anyone here mod their own amps?

j2b4osan

So I've been getting into amp modding so eventually I can move on to amp building. But I have manny questions and am not sure who to ask and prefer conversation to reading books because I can't ask a book what it means.

My main questions lie in what makes up a gain stage and how to manipulate it. For example will higher tolerance resistors and caps reduce or increase gain?

I have many others but let's start there. Thanks!

Fran

All i know is certain pre amp valves have more effect than others, like changing V1 is not as effective as changing V2 or whatever.

No idea at all on the caps and transistors. These are the guys you need to be mixing with...

http://www.vintageamps.com/plexiboard/viewforum.php?f=28&sid=a06e47ee66471b26fc74db2ebc58bb65

j2b4osan

ok so Ive started to mod the epi valve special so Im going to keep a log in this thread incase anyone wants to do it aswell.

here is the skeemat for it

http://www.sewatt.com/files/sewatt/sewa ... ematic.pdf

I have a different board but things are wired the same.

first thing I did was remove and bypass the dsp effects which opened up the amp cleared it up a bit and lowered the bass considerably (which I liked).

second thing I did was raise the gain by removing the resistors at R12 and R13. that made the gain come alive and give me some nice thick overdrive.

Ill be posting pics soon of the modded board so anyone can do it.

j2b4osan

put in all new apha 1meg audio pots in all positions. put in a 12" 8ohm warehouse retro 30 in it and the clarity is amazing. threw together a box quick cause the speaker didnt fit neatly in the other box. (other one was MDF anyway).