#1
I've got a frontman 15 I'm trying to improve (yeh I know, polishing a turd etc.) and I'm failing to understand the tonestack on it. Schematic can be found here http://support.fender.com/schematics/guitar_amplifiers/Frontman_15G_Schematic_68F.pdf

Basically I'm looking for a bit more of a marshally tone with less bass but if someone is able to explain to me how to follow it then I'll happily do the maths and changes myself.
Epiphone Les Paul Plus Top
Jet City JCA5212RC (SLO Modded)
Ibanez WD7 Wah
Mad Professor Sweet Honey Overdrive
TC Electronic Flashback Triple Delay
TC Electronic Trinity Reverb
#2
See R30-R34? Playing with those in addition to C20 will lead you in the right direction. I would try a 100n for C20 to start, after that, play with R33 in both directions, 100k trim should help you find a value you like. Another 100k trim replacing R31 & R32 using the wiper as the junction should provide some results, too. R34 in conjunction with the source impedance and C20 chooses the -3dB of the low-pass filter, and R33 allows you to dial in the bass somewhat. The rest of the stack is relatively unaffected by these changes.
#3
*hugs jared*

cheers mate, will try it out
Epiphone Les Paul Plus Top
Jet City JCA5212RC (SLO Modded)
Ibanez WD7 Wah
Mad Professor Sweet Honey Overdrive
TC Electronic Flashback Triple Delay
TC Electronic Trinity Reverb
#4
or I'll try it when I stop blowing fuses, gonna need to build myself a bulb limiter tomorrow for testing purposes *sigh*
Epiphone Les Paul Plus Top
Jet City JCA5212RC (SLO Modded)
Ibanez WD7 Wah
Mad Professor Sweet Honey Overdrive
TC Electronic Flashback Triple Delay
TC Electronic Trinity Reverb
#5
Here are layouts for Fender and Marshall tone stacks. I have never compared them to actual Marshall and Fender amps, so I ca'nt vouch for accuracy.
But It may be give you something to go on.




#6
My issue with that is that it isn't a standard FMV TS, that's why I specific to the schematic. If you are popping fuses left and right, you have a bigger issue than tone.
#7
wonder if you could put a FMV TS in on the pcb >.<

am aware I have bigger issues, paid a fiver for the amp :p just working on it as a side project
Epiphone Les Paul Plus Top
Jet City JCA5212RC (SLO Modded)
Ibanez WD7 Wah
Mad Professor Sweet Honey Overdrive
TC Electronic Flashback Triple Delay
TC Electronic Trinity Reverb
#8
For whomever is interested here is a Tone Stack Calculator for many popular configurations. If anything you can play around with resistor values and sweep through the estimated response curves. Pretty cool.

http://www.duncanamps.com/tsc/
#9
You probably could, I wouldn't though, just buy a small section of perf board and put the FMV on it, look at a way to mount the entire FMV tonestack on the pots, and just disconnect the tone stack section of the amp where it is, and connect to the FMV.

Good link LoveFuzz.