Slope Resistor Values - JCM800 2204 / 2203

[solterramatt]

Hi Guys,

what values do you guys prefer for the slope resistor in a 2203/2204
marshall amp?

33k? 56k? other?

how do the different values affect the tone of the amp?

i've got a JCM800 2204, so far i've done the following to it:

- removed the first treble peaking circuit, and replaced with a 68k resistor
- removed the 470pf cap from the second treble peaking circuit.
- changed the cathode resistor on V1B to 4.7k
- changed the slope resistor to 56k
- upgraded to Sozo caps.

at the moment i'm fairly happy with the results. haven't played the
amp enough yet for the Sozo's to form, so that should be interesting in
time. i've got more than enough gain to keep me happy.

the amp though is sounding a little bit too 'heavy' for my tastes, so
i'm starting to question my choice of the 56k slope resistor, but its
been a few months now since i replaced the stock 33k so i'm also
wondering if my mind is playing tricks on me! :S

just curious to see what you guys opinions on slope resistor values before
i start messing around with the amp again. also considering asking my
tech if he can install like a toggle switch in the back of the amp where
the DI output is, so i can switch between a couple of different slope
resistor values.

for reference, i dig more classic marshall tones, stuff like led zep, ac/dc,
but i also like to be able to go a little bit heavier than that gain wise.
i also hate it when my amps sound harsh.

cheers,

matt

[Billy Batz]

Use some jumpers to parallel a 68k with the 56k you have in there and see

[myker]

i like 47k
mike