Anyone knows some mods for Boss MD-2?

[gigimarga]

Hello all,

After I've searched a lot, it seems to me that there are no mods for Boss MD-2 (Mega Distortion)!!!

That looks very strange for me, because for almost all others Boss stompboxes there are mods...

Anyone knows some mods for it or MD-2 is the only perfect Boss stomp?

Thank you!

[gigimarga]

 

[anchovie]

There are mods, but they are commercial rather than DIY. I think most people who aren't completely happy with the MD-2 replace it with another pedal!

[edvard]

What are you looking for that the MD-2 doesn't do?

Looking at the schematic, it's a differential booster -> 2-op amp distortion stage -> push-pull transistor stage (for a touch of  crossover distortion, I assume) -> rather minimalist EQ stage (low-pass tone and gyrator-based 'bottom').
So it looks as if this is one of the few pedals touting a "modern" sound that doesn't employ gyrator EQ'ing all over the place, although the choice of 3 different types amplification in one design is somewhat unusual...

I'm not exactly sure how to go about modding this one, but I imagine some sort of tone shaping is in order to overcome the op-amp clipping noise, which is about all there is to this circuit.

[gigimarga]

Thx to both of you for your answers, anchovie and edvard!

The only mod that I found on Google is "weed mod" (http://item.rakuten.co.jp/dbltrbl/weed-md2/), but I didn't understand anything!

As edvard guessed, I think that the only lack of this pedal is that it has no possibility to shape the mids, especially to scoop the sound...

Thank you very much again!

[gigimarga]

Nobody knows more?

[gigimarga]

 

[R.G.]

Blind Urge to Mod Syndrome?

What do you want it to do that it doesn't do? If you don't know where you want to go, any road will work as well as any other.

[edvard]

As edvard guessed, I think that the only lack of this pedal is that it has no possibility to shape the mids, especially to scoop the sound...

I think that's OP's intent.
Looking at the circuit again, I'm wondering if the  "bottom" control could be hijacked into a "mid" control if we choose components carefully.
The other option would be to put a simple bridged or twin-t circuit on a piece of perfboard and solder leads from it to either side of a cut trace just in front of the final op-amp stage.

I've just been messing around with the gyrator calculator at Muzique (http://www.muzique.com/lab/gyrator.htm) and I couldn't get it to do what I had in mind, but then I remembered that gyrator is there to simulate an inductor for a Low-Pass filter, not Band-Cut.
Hmmm...

[gigimarga]

Blind Urge to Mod Syndrome?

What do you want it to do that it doesn't do? If you don't know where you want to go, any road will work as well as any other.

You're right R.G., as usually...I have only a little time for DIYing, so I have a fever of modding

Anyway, all that I want from it it's a possibility of tweaking the mids

Thank you!

[gigimarga]

As edvard guessed, I think that the only lack of this pedal is that it has no possibility to shape the mids, especially to scoop the sound...

I think that's OP's intent.
Looking at the circuit again, I'm wondering if the  "bottom" control could be hijacked into a "mid" control if we choose components carefully.
The other option would be to put a simple bridged or twin-t circuit on a piece of perfboard and solder leads from it to either side of a cut trace just in front of the final op-amp stage.

I've just been messing around with the gyrator calculator at Muzique (http://www.muzique.com/lab/gyrator.htm) and I couldn't get it to do what I had in mind, but then I remembered that gyrator is there to simulate an inductor for a Low-Pass filter, not Band-Cut.
Hmmm...

Thank you very much edvard for your kindness and help...it seems to me that's too complicated to mod MD-2...maybe I will try to add a twin-t circuit as you said...many thanks again!

[WGTP]

It looks like the 10K/27n to ground are doing some high freqency shelving.  Might mess with that some in conjunction with the tone controls.  Also might be a place for the bridged T.   

[gigimarga]

It looks like the 10K/27n to ground are doing some high freqency shelving.  Might mess with that some in conjunction with the tone controls.  Also might be a place for the bridged T.   

Thank you very much WGTP!

I will make some tests as soon as I will have some time for modding

[frank5150]

Hi folks! (Sorry in advance for my bad english...) This my personal mod to Boss MD-2.  IMHO that's a very interesting distorion pedal but MD-2 needs more "body" and "fullness". That's my easy mod to increase the mid/bass response of pedal. If you see the board, you can find empty component position for R49 and C19. Try 1k5 in R49 and 1u5 in C19. http://mrotqch.webcrow.jp/stomp/zoo/Boss_MD-2.png
I hope you like this trick 

[frank5150]

Sorry, the empty cap position was C18 (try 1u5 electrolityc) and not c19

[czech-one-2]

Sorry, the empty cap position was C18 (try 1u5 electrolityc) and not c19

Thanks, that is a nice improvement! I used a 1uf cap. I wonder why they drilled the boards but omitted the components?

[Gila_Crisis]

Just found one of these for very cheap so I gave it a go, also to understand why everybody talks bad about this one.
Actually I like it, it has its own caracter and voicing (kind of a woody tone).

Here's what I did to mine, to remove the fix and add a bit more overall body to the pedal:
C9 47n
C10 2n7
C7 3n3
R21 47k
R73 Jumper
C40 10n
R49 1k8
C18 1uF

[Gila_Crisis]

I did few more fine tunings to the pedal.
I swapped R13 and R42 with 220 ohm resistors. It helps a lot! you have a bit less gain and fizz (well... if you max both Dist and Boost knobs you still have tons of gain available), and also a bit less floor noise.
Then in the Bottom control I tuned the gyrator so that is centered around 80-90Hz (I thing I always borrow from the HM2), which means C100 150nF and C30 82nF.

Then:
R69 10k
C40 22n
R77 (it's on the pot board) jumper (this way you have way less gain when Dist is at Zero, so that you can use only the Gain boost to achieve some cool overdrive sounds!)

I must admit with the mods you can fine tune this pedal a lot, and it's a very good pedal and interesting design. Odd that until now it received so less attention.