Montarbo Sinfhoton

Here’s a pedal that caught my eye while looking for a new fuzz. It was made by an Italian company in 68.

It’s very Big Muff like in tone, but seems to have a bit more clarity in the notes, and no Fuzz control, just Bass, Treble, and Volume. In my search for the schematic I found that over time there’s been 3 different versions, so I made a layout for each, and then found that a few years ago by Miro actually made a layout for the later version. My layouts are a bit more compact, has less cuts & jumpers, and I put the CLR for the LED on the board, so I thought I would still post all of them, since while they have the same feel, each sounds a bit different.

Also, through my searching I found some mods people have done, and made a massively modded layout as well that I’ll post later with a description of it all.

The video compares the stock vintage unit to a clone made by Brad at Creepy Fingers. Not sure what the extra pot does, but since it’s full CW I can only assume it’s a Fuzz Pot.

Earlier Version

Later Version

2 Knob Version

Notes:

  1. You may need to adjust the 2 10k resistors to the Collectors of Q1 & Q2 to bias the transistors  right and have it sound good.
  2. Since BC149’s are hard to come by, although I’ve seen them on eBay, you may want to try the usual suspects with higher gain. So transistors like 2N5088/2N5089, MPSA18, BC109, BC108, etc.
  3. For the 2 knob version you may want to change the 2uF caps to 10uF caps like the later version.
  4. For more fuzz remove the 100k or 1M resistor parallel to D1 & D2. 
  5. I left out the usual 1M pulldown resistor as in all the videos I heard I
    didn’t hear a pop from the vintage unit, so I felt it’s not needed, you can always add it on the switch or just add an extra column.

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