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Vintage threads from the first ten years

Marshall Mods/Trace Allen/etc......

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9/30/1999 7:04 PM
Fj	Marshall Mods/Trace Allen/etc...... Holy-Sh%t dude!!!...tacked in a 350pf onto the .022 orange-drop on my PLEXI/JTM 45...(didn't have a 330pf!)...smooth, SWEET, FATTER...LEADS!!!...cool, thanx!...Frank.

9/30/1999 7:51 PM
Fj	now...can ...or...will this "mod" funtion correctly in my 76' MV Marshall?...also...in what way will a 500pf vs. a 250pf cap across pin #2 of PI effect tonality?...(brighter...500pf...or...brighter...200pf?)

9/30/1999 8:09 PM

quote:
"now...can ...or...will this "mod" funtion correctly in my 76' MV Marshall?"

It should work fine. Put is across C9 (.022uF)in the 2203/2204 amps. It's the .022 that goes from the Master Volume to the Grid of the phase inverter tube. I've installed this in many Master Volume Marshalls and it's always sounded good.

quote:
"also...in what way will a 500pf vs. a 250pf cap across pin #2 of PI effect tonality? ... (brighter ... 500pf ... or... brighter...200pf?)"

I assume you mean across the .022 cap that goes into pin #2? If so, I've found that the 500pF makes the tone much "fatter" and much more obvious than than the 330pF. The mids become even more "in your face" and the over all tone is more "compressed." You may like it, try it and see. Again, 330pF was the magic value for me is all. The 250pF cap will make the effect less noticeable. If you go up in cap size you get a more compressed tone and trim more highs.

let us know how it works for you!
Trace

9/30/1999 7:59 PM

quote:
"Holy-Sh%t dude!!!...tacked in a 350pf onto the .022 orange-drop on my PLEXI/JTM 45...(didn't have a 330pf!)...smooth, SWEET, FATTER...LEADS!!!...cool, thanx!...Frank."

I'm glad you like it Frank :-)

:-)

Now that you have that in your amp maybe you can describe in words what it sounds like and what it adds to the tone! (ha, ha) I've had a hard time describing it so people get the idea of what it does.

PS: try tacking a 300pF (or what ever is close) across the 47pF cap that is connected to pins #1 and #6 of the phase inverter tube. It sounds pretty cool.

Thanks!
Trace

9/30/1999 8:17 PM

ok here goes :}...when you listen to the TROWER "LIVE" album, he uses a wah-pedal to "catch a sweet-spot" for his LEADS...ok...in a way, this amp was kinda' harsh (lots' O ' gain)...VIA Hoffmans' "GAIN MOD" that I also have tapped into this amp...enter 350pf...it kinda "hones-in" on that elusive "sweet-spot" (the wah pedal thing)...while ADDING, IMHO, a titch-more upper- LOW-END kinda' vibe...also a little LESS harsh...Frank

10/1/1999 12:38 AM
Blues Lyne	Trace, Any reason this wouldn't work on a BF Fender? Blues

10/1/1999 1:03 PM

That's the thing with Trace's mods. You just have to try them and see what happens. That seems to be how Trace works, and I've had such amazing results I guess he must have a pretty keen pair of ears.

I'd suggest you have a go at these type of tricks with any tube amp with similar circuit topology. You might have to try a few values before you get what you want, but the right values are bound to be in there somewhere. Rotary switches with a good few alternative capacitors to select are quite a nice way of testing. It's nice to be able to compare directly.

If you don't try it, you won't learn anything!

Liam

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