Bad Monkey mods for you

[grolschie]

(re-posted as a new topic)

does naybody kno, any mods for the digitech bad monkey?

TS808 mods are possible, R52 is the shunt resistor and C32 is the coupling cap after the output buffer transistor Q9. There is no series resistor, but one can be added. The signal forks after Q9 into the coupling cap (normal output) and the amp sim ouput.

D2 is a surface mount dual diode combo. Replace this with clipping diode combinations of your choice.
The TS808 mods are subtle at best. Even removing R52 completely sounded pretty much the same. The stock BM is a winner already.

[grolschie]

I will simplify this somewhat with pictures. Bajaman helped me do mine, as the SMD stuff is a pain and I kacked mine up and tore a track whilest fidding with a SMD resistor.  Arrgh!  Mess! Also, thanks to Bajaman I learned that you don't need to use SMD components! You can stand resistors on their ends!!!

Please note that this not real tidy looking, but it works! :-)

The Bad Monkey to TS808 mod (well kinda):
-ref: http://www.geofex.com/Article_Folders/TStech/tsxtech.htm#obuffer

- The Series resistor:
A 100ohm series resistor needs to be added between the output buffer transistor Q9 and C32. You can easily do this by de-soldering the positive leg of C32 and attaching one side of a 100ohm resistor to the leg, and the other side of the resistor to the board. You can see this here:
http://s220.photobucket.com/albums/dd249/grolschie/Digitech%20Bad%20Monkey/?action=view&current=badmonkey_series_resistor.jpg

- The shunt resistor:
R52 needs to be changed from 100k to 10k.  In the previous picture you can see where I messed up by tearing the R52 track. Instead Bajaman soldered a resistor to the back of the PCB as shown here:
http://s220.photobucket.com/albums/dd249/grolschie/Digitech%20Bad%20Monkey/?action=view&current=badmonkey_shunt_resistor-1.jpg

Diode Mods:
Bajaman also removed SMD D2 diode combo and replaced with a triangular arrangement of normal diodes (1 silicon diode going one direction and 1 silicon + 1 germanium going the other). The good old goop to the rescue held it in place nicely. Afterward I added a switch to short the germanium diode to return it to stock setting.
http://s220.photobucket.com/albums/dd249/grolschie/Digitech%20Bad%20Monkey/?action=view&current=badmonkey_diodes_switch.jpg

Installing the switch:
Not much room for a switch, but I managed to squeeze one in. It was a tight squeeze between the input jack and the gain pot:
http://s220.photobucket.com/albums/dd249/grolschie/Digitech%20Bad%20Monkey/?action=view&current=badmonkey_diodes_switch2.jpg

I quite like the germanium diode feel, but not the asymetric clipping. So I might modify this slightly to switch in and out 2 germaniums instead of just one.

[JHS]

The BM is a stock TS-9 clone with an added bass control. The 100E is factory installed (2x220E parallel) , so there's no need to add it.
I recommend to connect the 4,7k/47n RC-combination, wired to VREF on IC1a, to ground for a more natural disrtortion.

JHS

[wampcat1]

The BM is a stock TS-9 clone with an added bass control. The 100E is factory installed (2x220E parallel) , so there's no need to add it.
I recommend to connect the 4,7k/47n RC-combination, wired to VREF on IC1a, to ground for a more natural disrtortion.

JHS

Thanks JHS! Any idea what type of bass control? probably just a quick and dirty gyrator at about 150hz or so?
bw

[MKB]

It also helps to replace the op amp (the one near the clipping diodes), I replaced mine with a RC4558, really smoothed out the tone.  But it required wiring a normal DIP8 op amp to a SO8 footprint, which was HARD.  Luckily there is quite a bit of room between the PCB and case above the op amp for the sky wiring.  And in this case as well, epoxy is your friend.  It's too bad Digitech used SMD components and the wierd pots in this pedal, it would be fantastic for modding if it had through hole components.

[grolschie]

After recently installing MOSFETs as clippers in a TS-7, I did this also to my Bad Monkey today - but with different germaniums. Is MOSFET clipping supposed to distort a whole heap more than silicon diodes? The pedal seems a heap more dirty, and more bassy too. Cleaner sounds are not as easy to obtain now - which is ok, but not what I was expecting.

[ninjaaron]

Has anyone tried replacing one of the diodes with an LED?

also, first post, yay.