Mejorar un TURBO overdrive OD-2r de BOSS?

#1 por MIKE HAMMER el 02/10/2014
Hola a todos. Aunque ahora ando inmerso en varios proyectos abiertos (terminal mi kit de Marshall TMB 18W (al 90%), su correspondiente pantalla (al 85%), me tengo que hacer un delay (empezando), una caja AB+BUFFER otra caja AB de salida (proyectado) y terminar de montar una strato (que dejaré para tiempos mejores o cuando llueva mucho).... tocando en casa con mi antiguo TURBO overdrive OD-2r de BOSS, he pensado que mirando un poco por ahí, seguro que algo puede hacerse para "mejorarlo".

asique primero os pregunto a vosotros, expertos, que creeis o sabeis que puede hacerse en un TURBO overdrive OD-2r de BOSS para mejorarlo? Así a primeras lo primero que se me ocurre es que cuando activas el turbo (el pedal tiene drive y "turbo") el pedal suena mal de cojones, asique que creo que la mejor modificación posible está aquí.

empezaré en mis ratos libres a documentar sobre este pedal, si alguien se anima a ayudarme bienvenido sea.

un saludo

feel the hammer MF!/

#2 por MIKE HAMMER el 02/10/2014
He conseguido esto, para empezar no está mal
Archivos adjuntos:

feel the hammer MF!/

#3 por MIKE HAMMER el 02/10/2014
y en ingles he leido esto en otro foro:

possible mods, mess with the lp filter, r48, c32
r35, c22 HP filter
r33, c25 mess with gain on turbo
c31, mess with input cap on overdrive
r47, c30 mess with combo for gain structure, more/less gain on od
d9, d10, d11 diode changes
c35 output cap for turbo
c4/c5 final output cap (c5 affects bypass too)
c33 input cap on turbo

asique miraré si esto es correcto, porque me parece que se refiere a R38 (NO R33 Y C25) para lo que yo quiero

de todas maneras a ver si alguien me ayuda con el INGLES sobre todo esto:
I've just finished a round of interesting mods for the OD2. They're for the turbo section and sound really good to me. If I am mistaken about any info or calculations in this post feel free to correct me. Smiley

Here it is...

1) Cut the trace that leads from the r17, Q6 junction to R11. Make the cut right before the trace gets to r17 and Q6 were it's already pretty thin. This location will be the destination for the jumper in step #2 .
2) Run a lead from the Q1, r8 junction to the Q6, r17 junction. The step sends full power (8.2V) to Q6 instead of the starved 5.6V.
3) Remove D6
4) Adjust the RT1 trim (with you DMM) pot so that it splits the power evenly instead of the factory offset.

At this point we have made the turbo section receive full power just like the regular OD section so you'll no longer have the starved clipping op-amp sound. What's different is that the turbo section has 2 cascaded discrete op-amps instead of 1 like the regular section. So, now you can play with the gain response of the first and second discrete op amps to get a gain structure that you like. Both are set up with a gain of about 50 or so. Multiply those stages and you have a total gain of over 2500! I wanted to maintain some of the flavor of the regular section though...

5) Tack two (or three, or four, or...) diodes across C28 (might have to use leads or remove c28 and make a little diode/cap module) to put them in the
feedback loop just like the regular section of the OD.
6) I lowered r35 to 100k to bring the gain in stage 2 down to around 20 and left stage 1 the same for a total gain of around 1000 when maxed.
7) Reversed r39 and r32. As it is normally, it's about a 2 out of 10 volume. Reversed it's about an 8 out of 10. Much louder!
Cool Changed C33 and C35 to .1uf for more bass in the turbo stage.

I'm sure there are many thing one could do to the gain/voicing/clipping options of this mod to get a nice result. Maybe someone would rather have lower gain in the first stage and higher in the second, clipping diodes in the second stage, clipping diodes to ground between stages, etc. As it is right now I can't even believe it's that same turbo stage that I once hated. It's smooth, powerful, and much much louder than the regular OD. It can do clean boost well and with the gain cranked it's a pretty wild ride!
If you could manage to "borrow" (via a switch) the other half of the dual gang pot that is not in use when the turbo is engaged, you could adjust both gain stages in the turbo section simultaneously ala the BD2 and Mark Hammer's "The Crank". Both of the pedals mentioned use the dual gang pot in a different way so I guess it's up to the person to decide whats best for them. The one last thing I thought of is to rehouse it and have a foot switch for the turbo mode. Maybe someday...
My question is, can the diode compression trick be used here?

feel the hammer MF!/

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