how I can mod the bass of one marshall 8080 (valvestate)???

[mr_winter]

I´m so sorry for the off-topic question...

hi friends!!!!

recently, I have a marshall 8080 valvestate & his bass control tone is too limited!!!

I try changing the pot (log. 100k... yeah... log... not linear...) for one 100k log & 100k lin... & nothing.... after for 250k... 25k... nothing!!!!

after, I change the medium pot (5k lin) for 10k lin & the bass dissapear!!!
I think that this is a balanced circuit... & the mid. section (in max. position) eats any bass presence & the bass that offer this amp is very limited... I need have much more bass!!!!
If I change the cap. of 22nf on enter of pot for another one of 47nf?

HEEELLLPPPPP!!!!!!!

[mr_winter]

the control pots are of clean/crunch channel...

I include image for analysis...

[smoguzbenjamin]

If you replaced the pot, for the same pot value but a different taper (eg lin or log) then you're doing something wrong. The bass control should work fine, or at least the same,  if you used the same value. Try putting the original back in and report back.

[mr_winter]

ohh yeah my friend smoguzbenjamin... I know... If I replace a lin for a log & viceverse, the response are not the same...
but the problem is that the middle pot response eats the sound of bass pot. & I have to put it in first quarter (middle pot.) of his travel...
...& come to me in this way!!! I need modify something of EQ circuit for obtain more bass...

[smoguzbenjamin]

You've got interactive pots then. Dang you'll have to use a completely different tonestack if you want to get rid of that. Or you could do what many people are starting to do and build your own amp!

[ahermida]

Have you tried running the tone stack simulator at Duncan Amps?  You can find out what the response of the circuit that you have now and by changing the components you can check what would happen.  

The link is at  www.duncanamps.com/tsc/index.html


Alf