Dismiss Notice

Psst... Ready to join TalkBass and start posting, make new friends, sell your gear, and more?  Register your free account in 30 seconds.

Big Muff Mod

Discussion in 'Effects [BG]' started by Basstyra, Apr 29, 2005.


  1. Basstyra

    Basstyra Commercial User

    Apr 3, 2005
    France
    CTO @ Two notes Audio Engineering
    Would anyone be interested in my mods on my Big Muff ? Hm, I don't really care, I like to share what I'm doing, especially when it's working ! :smug:

    So, the subject is my russian muff. I allready add a boss type DC input. I switched for a blue led, as Fozzy did (I really LOVE that mod !! :hyper: ), and I'm curently working on THE big mod : adding a // dry loop right inside the box (and True bypass mod of course, but that's the easy part).

    Indeed, you all noticed that the muff used alone eat all your attack and bass. For me, it is simply unusable like this. I use my Boss LS-2 to add a // dry loop, but I want to free the LS-2 for other purposes. And as an electrical engineering student, I wanted to work on real projects, because theory is good, but I realized soon that it's nothing when it comes to reality...

    So, the facts.
    Here is my current schematic :
    [​IMG]

    The caps are 0.1 mF.
    It works, but I don't know if it will be the final schematic. I have to make tests on my amp.

    Here is what my bed looked like 1 hour ago... :)
    [​IMG]

    I think I will finish this next week. I'll let you know, and if someone is interested, I can give all the infos. It would work with any pedal.

    Feel free to ask any question or make any remark !

    I'm really happy, my first real electronic project is working ! :hyper: :hyper:
     
  2. tplyons

    tplyons

    Apr 6, 2003
    Madison, NJ
    I've done it a few times, but I usually make a seperate, small wet/dry loop box. Looks liek yours will work.
     
  3. fozzy

    fozzy

    Jun 21, 2001
    Riga, Latvia, EU
    Yes, i think that stand-alone dry/wet box will be more useful. You don't need to modify BigMuff itself. This is what i'm doing myself(ok, ok, guitarist helps me, he's better at electonics and stuff than me). All I can say - good luck :D
     
  4. mosca

    mosca

    Feb 7, 2005
    what is a dry/wet box? do you have a picture of one?
     
  5. tplyons

    tplyons

    Apr 6, 2003
    Madison, NJ
    A wet/dry box is a looper with a blend control between the signal through the effects loop, and the original unaffected signal. This is quite useful in the case of effects that REALLY lose bottom end, you can get the grit you want while retaining the boom you crave.
     
  6. Basstyra

    Basstyra Commercial User

    Apr 3, 2005
    France
    CTO @ Two notes Audio Engineering
    The advantage of what I'm doing is that I can keep the original signal volume (passive blend pot allways loose a little volume).

    I tested today on my amp. It works, but it's a little noisy. Bad op-amp, parasites, DC problems, I don't know. I'll try some things, and if I can't fix this, I'll let it this way. The purpose is to do lots of noise with a Muff, so... :)
     
  7. Basstyra

    Basstyra Commercial User

    Apr 3, 2005
    France
    CTO @ Two notes Audio Engineering
    Here is my final schematic :
    [​IMG]

    I allraedy did the True bypass, I just have to make the circuit, and finished !
     
  8. Basstyra

    Basstyra Commercial User

    Apr 3, 2005
    France
    CTO @ Two notes Audio Engineering
    Job Completed !!

    Ok, it's late, I'm exhausted, but it's finished !!

    The board looks like that :
    [​IMG]

    Rear view :
    [​IMG]

    The whole thing inside the box :
    [​IMG]

    Lots of wire...

    And my Big Muff Basstyra's Custom all put together :
    [​IMG]
    [​IMG]

    I tested it (du to the time, I tested it at low volume...), and it worls, but I have to test it at normal volume.

    My first "real" project in electronic is working, I'm happy !!

    Thanks to Fozzy again for the Blue Led thing, it really adds something... Thanks to Moosapotamus, your webpage made me begin. The final stuff is a little different as yours, but the result is quite the same, I think.

    Oh, I almost forgot...
    :hyper: :hyper: :hyper: :D
     
  9. Nice job! Congratulations! If it's doing what you want and it sounds good, that's all that counts. :cool:

    So, what are you giong to build next? :eek:

    ~ Charlie
     
  10. Basstyra

    Basstyra Commercial User

    Apr 3, 2005
    France
    CTO @ Two notes Audio Engineering
    Hm, I don't know. I'm thinking next of a simple true bypass on my AX-1B (which isn's so simple because there isn't much room for a footswitch).

    Or maybe I'll do what I planned some months ago, and never had the courage to begin : a double input preamp, which I would use for my lessons (I play on a PA in my music school, and it sounds awful. The double input is for when I play on a single input amp with a student.). It would be much cheaper and much more interessant to built it than to buy a Sansamp ! But it's still a lot of work, so I think I'll do that, but I don't know when...

    If I were really courageous, I would try to change some caps or resistors in the muff to see how the sound can be modified, but as I'm happy the way it currenctly sounds... I think I'll try to find damaged pedals to try things like that.

    Anyway, this achievement gives me self-confidence, so I think it's only the beginning ! :)

    EDIT : I just took a look at your page again, I found some interesting links... Tha Aron Stombox Forum seems interesting... :smug:
     
  11. fozzy

    fozzy

    Jun 21, 2001
    Riga, Latvia, EU
    Basstyra, we need the sound clips :D
     
  12. Basstyra

    Basstyra Commercial User

    Apr 3, 2005
    France
    CTO @ Two notes Audio Engineering
    I'm working on it. I hope I can do it today. ;)
     
  13. Basstyra

    Basstyra Commercial User

    Apr 3, 2005
    France
    CTO @ Two notes Audio Engineering
    Ok, the soundclips will come later. But for now, here are some more informations on how to do this mod yourself...

    First, I think a true bypass mod is more than usefull... While you're modding this pedal, why not take this opportunity ?

    So, the schematic is that :
    [​IMG]

    There is a Bias at 4.5V to allow a sweep from 0 to 9V. The opamp are powered with 9V.

    The dry loop volume pot is a log pot, of course. I put a 250k because I had this in stock, but I wonder if a 25k wouldn't be better.

    Notice that in order to true bypass, you'll have to mod the input jack :

    Behind,the circuit is cut :
    [​IMG]

    Front, the green wire takes the input signal :
    [​IMG]

    The green wire goes to the footswitch.
     
  14. dadodetres

    dadodetres

    Dec 19, 2004
    URUGUAY
    hey! im reciving mine in some days or weeks (hope its days) and want to know if i can do this mod for an USA big muff.

    i know VERY little electronics, and have ittle experience soldering, but i have big common sense, would i be able to do it myself? or should i ask as firend who studies electronics to help me out?
     
  15. fenderx55

    fenderx55

    Jan 15, 2005
    NYC/Queens
    hey, would putting a blue LED in a double muff work...and any thoughts on adding a master vol. pot to it? i'm in the same boat (little electronics knowledge...except i can solder...ish).
     
  16. Basstyra

    Basstyra Commercial User

    Apr 3, 2005
    France
    CTO @ Two notes Audio Engineering
    The blue led mod is "plug and play" on every pedal. Just change the led. Stomp the switch. Here you have ! :)

    Adding a general volume control is really easy. It's just adding a pot. You should add it "before" the bypass, at the end of the effetc. Locate the wire that goes from the effect (the board) to the switch. Desolder it from the switch, solder it to one end of the pot, solder the other end of the pot to the ground, and solder the switch, where was the wire before, to the center pin of the pot. But the exact location where you can/should put the pot may not be the same, depending on how the bypass is wired. For example, on the schematic down there, it would be just after the last resistor.

    Realising the dry // mod is not very hard, you have the schematic, I will put the perfboard schematic soon. But you probably should adapt it to your case if your Muff isn't true bypassed.

    You can do this on almost every pedal, every pedal with a mecanical switch.

    My full schematic is that, true bypass (the switch is a relay, but you'd better do this with a 3pdt, the 3rd way would be for the led) :
    [​IMG]
     
  17. seanm

    seanm I'd kill for a Nobel Peace Prize! Supporting Member

    Feb 19, 2004
    Ottawa, Canada
    Looks very professional :cool:

    Just curious though, why did you invert the output?
     
  18. since you inverted the output does this mean the inputs and outputs are reversed like my "special" big muff. it's odd alright
     
  19. Basstyra

    Basstyra Commercial User

    Apr 3, 2005
    France
    CTO @ Two notes Audio Engineering
    The schematics has been done with Orcad demo. ;)

    What do you mean, I inverted the output ?

    Here is the perfboard plan. You can see it up there.
    I put the numbers on the schematic, have a look.

    [​IMG]
     
  20. seanm

    seanm I'd kill for a Nobel Peace Prize! Supporting Member

    Feb 19, 2004
    Ottawa, Canada
    All the opamps marked "Buffer" are non-inverting, but the final opamp marked "Unity Gain Sum" is inverting. So the output will be inverted (180 degrees out of phase) from the input.