FV-1 multi effects unit

This is my take on the FV-1 multi effects chip, I’ve taken elements from the datasheet, Hagiwos version and a couple of other FV-1 designs I found on the web.

I’ve added a version of my programmer to it to control an 8 channel DAC and a pair of shift registers to generate 16 switched outputs.

Using 3 external eeproms I can select upto 32 variations of effects and then create 999 patches of these using the 3 variables pots and the wet/dry mix pot.

It is midi controlled as well with each parameter available as a CC. And patch recall over midi.

Stereo/mono inputs and stereo outputs.
Thinking of adding a foot switch option as well to enable/disable the effect.


gr8 to see your still at it, with the GAZA stuff going on the “issues” in your neck of the woods are taking second fiddle. standards news broadcasting, old war , old news…

Anyway never seen the fv-1 befor , but your work on stripboard is always inspiringly complex!


Cheers, the FV-1 is new to me too, I only came across its used in the Jeannie synth that I’m building as a multi effects.

On our 11th air raid siren of the day, sleeping in the basement.


FV-1 was designed for guitar pedals. Probably the only IC ever designed specifically for guitar pedals. It is used in many, many guitar pedal designs. I have built 3 with it, a multi-mode reverb, a multi-mode delay, and a rainbow machine. Rainbow machine doesn’t even need the eeprom. It just uses the default program.

I didn’t realize that Hawigo’s multi effect module used the FV-1.

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I’ll be happier when work out how to use the eeproms, currently I’m stuck with just the factory settings until I can work out how to program chips.

Do you have an eeprom programmer? You can use a RPI or an arduino to program them, but an eeprom programmer is easier.

I have both, eeprom burner and plenty of arduinos etc.

Not sure if my burner supports 24LC32 chips, I need to check

Writing programs for these things looks painful. I think I will stick to the Daisy for my DSP programming needs.

Also, pedalpcb sells a pcb (and has the schematics if you want to make your own) that is a programmer/development platform for the FV-1. It is based around guitar pedals, though. May still get you going in the right direction if you need a development platform.

I don’t need PCBs, this is a one off at the moment, although I do have 6 more fv-1 chips to play with. I might build some add on effects modules for some of my synth designs, currently they are either effect less or using stripped down Behringer june-60 devices.

Shamelessly stole Hagiwos method for displaying parameters and added the patchname/number, bank number/effect and the effects mix, a tight squeeze. I’m thinking of putting a large 3 digit LED next to the display so you can see the current patch number from a distance.


I believe it’s pronounced Research?


Added the display today.


That’s another great looking peice of work

Very close to the finished article…



Well done.

(plus 20 character)


… This would be the said article. How, can you spare a moment to discuss your process/mindset when starting and finishing a project?

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sure, what do you want to know?


You are inspiring me to rack mount all my future projects.
I just wish the cases were cheaper.

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