Home › Forums › Help/Technical Questions › Muff Fuzz Wiring?

Viewing 14 posts - 1 through 14 (of 14 total)
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  • June 6, 2009 at 5:42 pm #78362
    devnulljp
    Participant

    Can anyone tell me where the black – wire from the battery clip should go in an old IC Muff Fuzz?
    Mine goes to the sleeve of the output jack, which also then runs a wire across to the pot, doesn’t seem right.
    What’s the sleeve of the input jack connected to? Mine runs a wire across to the pot — I’ve seen gutshots of others where it looks like it connects closer to the edge of the board.

    I’m wondering if I’m missing some capacitors too…although there is a .1 uF on the underside of the board next to the output jack.

    Shouldn’t the input jacks be stereo with the -ve battery input going to the ring? How’s this thing grounded?

    Thanks

    th_mufffuzz-guts-04.jpg
    th_mufffuzz-guts-03.jpg
    th_mufffuzz-guts-02.jpg
    th_mufffuzz-guts-01.jpg

    I get lost trying to follow this schematic

    June 6, 2009 at 5:57 pm #97459
    The EH Man
    Moderator

    The sleeve of the jack is OK. It doesn’t use a stereo jack because when you turn the effect off it also disconnects the battery lead.

    June 6, 2009 at 10:56 pm #97470
    devnulljp
    Participant

    Thanks — any idea what would cause large amounts of white noise in that circuit? I cleaned the switch and the pot, but it’s really noisy.
    Capacitors next?

    June 6, 2009 at 11:03 pm #97471
    The EH Man
    Moderator

    Electrolytic caps would be next. Is that unit transistor or IC?

    June 6, 2009 at 11:19 pm #97473
    devnulljp
    Participant
    Quote:
    Electrolytic caps would be next. Is that unit transistor or IC?

    It’s a 1977 IC model.
    There’s one polarised electrolytic underneath the board, along with one of those little green chicklet caps and a big orange one, then there’s the ones you can see on top. Replace all the caps or just that polarised electrolytic? Those orange ones are ceramic?

    June 6, 2009 at 11:22 pm #97474
    The EH Man
    Moderator

    Just replace the electrolytic. If that doesn’t help, replace the IC.

    June 7, 2009 at 4:50 am #97483
    devnulljp
    Participant
    Quote:
    Just replace the electrolytic. If that doesn’t help, replace the IC.

    What’s a good choice op-amp? The one that’s in there looks like MC1458, but the schem I found has 4558, like a tubescreamer.
    (How about OPA2134 or TLO72? Totally unsuitable?)

    mufffuzz-opamp_0001-1.jpg

    June 7, 2009 at 10:30 am #97490
    The EH Man
    Moderator

    I’d go w/ 1458 or 4558.

    June 12, 2009 at 7:23 am #97780
    devnulljp
    Participant

    I swapped out the electrolytic and it made no difference. One thing I noticed though, if I touch my finger to the leg of the 470k resistor running off the op-amp the buzz drops to tolerable. Sound like I’m just grounding something or bridging something? Stray DC running to out?

    th_mufffuzz-guts-03-1.jpg

    I’m not convinced that resistor is in the right place from the schem but I’m not certain.
    In the pic above, the op-amp pins are ?:

    1—8
    2—7
    3—6
    4—5

    The schem has a 470k resistor bridging pins 6<-->7.

    June 12, 2009 at 10:55 am #97788
    The EH Man
    Moderator
    Quote:
    I’m not convinced that resistor is in the right place from the schem but I’m not certain.
    In the pic above, the op-amp pins are ?:

    1—8
    2—7
    3—6
    4—5

    The schem has a 470k resistor bridging pins 6<-->7.

    It’s hard to tell from the pics what’s there.

    June 15, 2009 at 10:23 pm #97947
    devnulljp
    Participant
    Quote:
    It’s hard to tell from the pics what’s there.

    I took some more pics — any idea? Thanks
    th_caps_0001.jpg
    th_caps_0002.jpg
    th_caps_0003.jpg
    th_caps_0004.jpg
    th_caps_0005.jpg
    th_caps_0006.jpg
    th_caps_0007.jpg
    th_caps_0008.jpg

    December 3, 2011 at 12:28 pm #116449
    Jasperdogg
    Member

    to: devnulljp

    I know this was an old post but I really gotta thank you for posting these pictures of the insides of the vintage Muff Fuzz. I have one that is in great condition, but I went to change the battery on it and the battery tumbled out taking the wires with it, breaking them clean off the solder points. I was totally clueless as to where the wires should attach even after using a huge magnifying glass. It just was such a clean break you couldn’t tell where they broke off of. From seeing your picture and reading a couple of the next posts I was able to repair my Muff Fuzz in totally good working order. It really was a helpful tool to know where to solder the wires back to. This was the only information that I found helpful after a ton of internet searches looking for clues. The schematic diagrams are not helpful to someone who isn’t into the electronics aspect of it and just looking for a simple repair.
    Any ways you might never read this since it’s been posted so long ago but much thank yous to you !!!! I thought my unit was done for .. but now it’s fixed!!!

    Jasperdogg

    December 3, 2011 at 12:35 pm #116450
    Jasperdogg
    Member

    to: The EH Man

    Thanks to your comment on the original post I was able to make a good decision on where to connect the black wire, and comparing that with the pictures taken on the original post I felt pretty confident that mine would be the same. My version was slightly different than the pictures but pretty close.

    Thanks! I was so happy to be able to fix my Muff Fuzz.
    I was also happy to see that they still seem to be much loved guitar toys still ;c) awesome sauce!

    -Jasperdogg

    September 21, 2013 at 5:36 pm #119365
    brucebennett
    Participant

    Thank you SO much for all the photos, I’ve had the same issue with my Muff Fuzz.
    and It seems that EH built these in several different versions.

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