silentrage
New member
Can anyone here help me out a bit with my rockmaster mod?
I tried a whole bunch of mods to see what differences they'd make, including:
C4 from .047uF to .47uF
C5 from 820pf to 2200pf
C17 from .47uF to 1uF
These are supposed to allow more lowend through.
R33 from 22kohm to 10kohm
R34 from 10kohm to 5kohm
These raised the preamp's voltage from 290v to 320v
R3, R13, R32 from 100k to 200k
These are supposed to cause harder clipping
After this the bass got too muddy so I restored the caps back to stock with the exception of C5.
Also played around with lowering R20 and R24, which seem to be V2's plate resistors, it made the distortion smoother but was too loose.
I did turn it on to hear how it sounds after each part swap, but somewhere in the process I noticed the bass was getting out of hand.
I remember before the mods with the boost pushed in the bass is kinda big and loose, and when pulled it's tight but a bit hollow. Now I seem to have made the pulled bass as big and loose as the "pushed-in" bass, and the current pushed-in bass is just overwhelming, flubby and not very playable.
Also there seems to be barely any distortion now withthe knob pushed in, and about 3-4 times the distortion with it pulled, I don't remember the difference being this big.
I've since restored each part to stock to see if it helps, but strangely enough I couldn't get the stock sound.
Right now I just have the R3,13,33,34 and C5 mods in place, the rest are all back to stock, and I've ran out of ideas.
Any help appreciated, the schematic is here.
http://www.schematicheaven.com/newamps/ ... preamp.pdf
I tried a whole bunch of mods to see what differences they'd make, including:
C4 from .047uF to .47uF
C5 from 820pf to 2200pf
C17 from .47uF to 1uF
These are supposed to allow more lowend through.
R33 from 22kohm to 10kohm
R34 from 10kohm to 5kohm
These raised the preamp's voltage from 290v to 320v
R3, R13, R32 from 100k to 200k
These are supposed to cause harder clipping
After this the bass got too muddy so I restored the caps back to stock with the exception of C5.
Also played around with lowering R20 and R24, which seem to be V2's plate resistors, it made the distortion smoother but was too loose.
I did turn it on to hear how it sounds after each part swap, but somewhere in the process I noticed the bass was getting out of hand.
I remember before the mods with the boost pushed in the bass is kinda big and loose, and when pulled it's tight but a bit hollow. Now I seem to have made the pulled bass as big and loose as the "pushed-in" bass, and the current pushed-in bass is just overwhelming, flubby and not very playable.
Also there seems to be barely any distortion now withthe knob pushed in, and about 3-4 times the distortion with it pulled, I don't remember the difference being this big.
I've since restored each part to stock to see if it helps, but strangely enough I couldn't get the stock sound.
Right now I just have the R3,13,33,34 and C5 mods in place, the rest are all back to stock, and I've ran out of ideas.
Any help appreciated, the schematic is here.
http://www.schematicheaven.com/newamps/ ... preamp.pdf