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Re: Marshall Tone-tweak Question

2/17/1999 8:29 AM
Chip	Re: Marshall Tone-tweak Question I've spent a lot of time working this particular problem. Here's what I do to my Master Volume Marshalls (most is applicable to 4-input type as well): Remove the .001 that's across the Preamp Vol pot. Change the 470pf cap across the 470k resistor after the first stage to a 250pf. Remove the 470pf cap that's across the 470K resistor after the second stage. Change the tone circuit resistor from 33k to 56k and cap from 470pf to 250pf, as Richie suggested. Change the feedback resistor from 100k to 56k. I run my tone controls as follows: Presence - 5 Bass - 10 Middle - 4 Treble - 5 or 6 This gives me a very fat tone. If one plays at lower volume a lot, try O'Conner's trick of putting a 100k on the out from the MV pot...... Also, if this one has the 6550's in it, check the bias. Many were shipped without proper bias set up (they just yanked the EL34's and put in 6550's), and have never been rebiased, due to the longevity of the 6550's. Hop that helps.... -Chip

2/17/1999 8:29 AM

Chip

Re: Marshall Tone-tweak Question

I've spent a lot of time working this particular problem. Here's what I do to my Master Volume Marshalls (most is applicable to 4-input type as well):

Remove the .001 that's across the Preamp Vol pot.

Change the 470pf cap across the 470k resistor after the first stage to a 250pf.

Remove the 470pf cap that's across the 470K resistor after the second stage.

Change the tone circuit resistor from 33k to 56k and cap from 470pf to 250pf, as Richie suggested.

Change the feedback resistor from 100k to 56k.

I run my tone controls as follows:

Presence - 5
Bass - 10
Middle - 4
Treble - 5 or 6

This gives me a very fat tone.

If one plays at lower volume a lot, try O'Conner's trick of putting a 100k on the out from the MV pot......

Also, if this one has the 6550's in it, check the bias. Many were shipped without proper bias set up (they just yanked the EL34's and put in 6550's), and have never been rebiased, due to the longevity of the 6550's.

Hop that helps....

-Chip

Replies:

Bruce Try putting a .0033uF cap accross t... -- 2/17/1999 8:57 AM