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Vintage threads from the first ten years

Plexi-clone "slope-resistor"...

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11/23/1999 12:09 PM
Fj	Plexi-clone "slope-resistor"... I know that this subject has been addressed in past threads...but...33K ,47K, 56K, 100K...which offers lowest-to highest frequency response parameter?...IOW...briter w / 33K...OR...briter w 56K?...Frank.

11/23/1999 12:48 PM
A.S	I´ve allways liked 56k and I think it´s brighter than 33k but you should check out this tone stack calculator and see for yourself. http://duncanamps.simplenet.com/tsc/ It seems like it has been updated so this goes out to all Ampagers - check it out! A.S

11/23/1999 3:51 PM

Hello guys....I don't agree with the 56k being brighter than Marshall's stock 33k...I have spent some time with this.My results....33k brighter,the amp appears to have more gain and is louder because the mids seem more apparant.

56K..WITH A 250 PF CAP in the tone stack..Is what Marshall used on their bass amps,and is more Fendery sounding....The 56k to me....mids scooped,warmer tone with less volume and less gain..This is Fender territory for sure..This will clean up your Marshall sound a little....maybe in the wrong direction depending on what you trying to achieve....I personally like the 33kwith the 500 pf cap in the tone stack for a Gibson Humbucker type guitar and the 47k for a single coil strat....Put a pot in place of that slope resistor,and see what you like....This is all subjective stuff..John S.

11/23/1999 10:16 PM
A.S	If you want to put a pot in place of the resistor, be sure to place a cap between the cathode and the tone stack. Otherwise you´ll end up with about 200V on the pot. A.S

11/23/1999 10:46 PM
Jeff	I have a '67 SL, and much prefer the 33k. I also like the nfb to be 100k off the 4 ohm tap. I run the head at 16ohms. Bias at 42ma. Jeff

11/24/1999 2:18 AM
John S.	Mine is pretty similar to yours,but I have a variable tone stack resistor pot on mine...I like 33k for the Gibson SG and close or at the 47k position for my Strats,but this also depends on the environment...Really helps tweak the amp to the cabinet.....John...

11/24/1999 4:53 AM
Jeff	John, What type cab/speakers do you use? I have an early 80's Marshall 4x12 with Celestion 65's. I was thinking about trying to find and old basket weave with greenbacks. Your thoughts? I'd like to know more about your Plexi too! Thanks, Jeff

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