PedalPCB Vibrobot/Frantone Electronics Vibutron 125b two mods

[OD is Glorious]

Build Rating

5.00 star(s)

I have built one of these before but it is long gone. This circuit has some wonderful tremolo and it can oscillate slower because of a mod suggested on this forum. It can also get helicopter tremolo with the toggle. This circuit is useable and I would be confident using it on my board. The Speed knob does what it says, it dials up speed... and the Depth knob controls intensity. The toggle goes between slow to fast and choppy. I have had the opportunity to build quite a few of the PPCB tremolo offerings but I think I like this one best so far. I have unity, when I noticed a volume drop on on tremolo, I adjusted the trim pot below 2N7000. Sounds great.

I used a 125b LMS limited powder coat drop called Killer Koi sparkle. I applied a film free decal and then applied a 2k clear coat. I like the look of blue with it, so I used a bezel-less 2mm blue LED and 20mm blue knobs. I love this limited orange color in person but FYI the enclosure's bottom is off by a shade or two. I used a PPCB top jack plate and enclosed jacks. Hot mink soft click footswitch with a PPCB 3PDT Breakout Board with LED.

The toggle is a Taiway DPDT on/on/on (type 2) with a dress nut. I built this one using two modifications which were discussed on the boards. Some builders in the forum suggested a larger capacitor at C6 to dial in slower tremolo. So For C6 instead of a 220nF film capacitor I used a 330nF. Some suggested a 470nF but this sounded sweet enough. I did socket it below the board so I could swap it out of 330nF did not accomplish slow enough tremolo.
For R21 instead of a 91k resistor I used a PPCB Trimmit with a 100k trim potentiometer (I set it at 93k) with a male/male pin header - note that I had to make bends in the pin header. For the 10u at C1 I used a non-polarized electrolytic capacitor.

See images to discover the way I did the small mods.

I tried the Davies 1510 knobs here but they looked out of place - see image.

Notes

1. For C6 instead of a 220nF film capacitor I socketed and soldered a 330nF. Some suggested a 470nf but this value sweet
2. For R21 instead of a 91k resistor I used a PPCB Trimmit with a 100k trim potentiometer (I set it at 93k because it was crisp) this mod was discussed as one to help stop distortion.
3. You have to adjust the trim potentiometer below the 2N7000 in order to dial in the tremolo. Small increments make big changes
4. You need a $5 ICL8038 PPCB has them.