Is this the lone tweak of Ed's plexi?
Posted: Thu Feb 23, 2012 6:32 pm
As many of you know I have the WoodyTone.com blog. Since I started that, several folks who appear to be in the know or were in the know about cetain artists' gear have posted comments that I haven't made public for various reasons. This is one I've been sitting on, had no luck getting in touch with the guy so here it is fyi. I am not an amp builder (yet), know squat about it so I can't comment on it...but I'm sure you guys can. Also, if it's old news, at least this may be some verification. Here 'tis:
Before the Dutch guy, before Suhr, the amp came to us at Soldano. I worked for Soldano in the late 80's-early 90's when Ed bought three SLO 100's (one of which he took to Peavey, which resulted in the 5150). Anyway, Ed's amp was totally stock except for the one little mod that everyone wants to keep secret. Well, here it is: On V2, there is a 820 ohm cathode resistor. Some plexis have this resistor bypassed with a .68 capacitor. Most Marshalls have no bypass cap here, just the 820 ohm. Well, Ed's amp had a 330uF electrolytic capacitor bypassing this 820 ohm resistor. If you look at Fender schematics for the tweed Bassman amp, Fender already tried this idea on the 5F6 Bassman (with a 25uF), but removed it on the next model, the famous 5F6A. Just adding that capacitor adds more gain than you might think. Add that cap to the Variac set at about 85 volts and all the other stuff, and there you are.
Before the Dutch guy, before Suhr, the amp came to us at Soldano. I worked for Soldano in the late 80's-early 90's when Ed bought three SLO 100's (one of which he took to Peavey, which resulted in the 5150). Anyway, Ed's amp was totally stock except for the one little mod that everyone wants to keep secret. Well, here it is: On V2, there is a 820 ohm cathode resistor. Some plexis have this resistor bypassed with a .68 capacitor. Most Marshalls have no bypass cap here, just the 820 ohm. Well, Ed's amp had a 330uF electrolytic capacitor bypassing this 820 ohm resistor. If you look at Fender schematics for the tweed Bassman amp, Fender already tried this idea on the 5F6 Bassman (with a 25uF), but removed it on the next model, the famous 5F6A. Just adding that capacitor adds more gain than you might think. Add that cap to the Variac set at about 85 volts and all the other stuff, and there you are.