Boss Tap Tempo DIY

Here is my latest build, a very simple tap tempo pedal for a Boss DD7 pedal (or any other pedal with external tap tempo). It is very simple : one mono jack, one momentary SPST! Very easy build, I think it is the perfect build to begin with DIY! Tap tempo is very useful if you play in a band, so I think this is really a great way to improve your beloved DD7 guitar pedal.

I used a Hammond 1590LB enclosure, which is really small. However, I did not centered the momentary switch because of the lack of space.

Boss tap tempo pedal



Unfortunately, these kind of enclosures are not available in a pre-painted form, so I had to paint it myself. I really do not like to paint enclosure, for many reasons, however I applied 3 layers of a very nice paint (Games Workshop Chaos Black spray ^^), that is actually quite nice for painting aluminum. It makes very thin layers that can last long I think. Then, I applied 3 layers of mat varnish. Lets see how it will age!

Boss tap tempo pedal


How does it work?

Ok, so the schematic is very simple, I have warned you:

Boss tap tempo schematic

No polarity here, very simple as I said. Only problem: some manufacturers use normally open switches, others uses normally closed switchs (Boss)! Pay attention to it.

It is a simple momentary switch that connects the 2 ring of the jack. Usually tap tempo is detected by a numeric IC by changing temporarily a 5V tension to 0V by connecting the pin to the ground while pressing the switch:
tap tempo schematic

This way, the microprocessor can calculate the time between each tap and adjust the tempo of the effect! This is the way my tap tempo Montagne Tremolo works.
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4 Comment
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Hi, do you think it's possible to add a LED that flash at the same time of the time?

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I think it would be possible but quite complicated. You'll have to "sense" the tempo that you used with your foot. From an electronics point of view it is quite a complex process that would require a microcontroller.

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BTW, is it a normally closed switch you are using?
Thanks

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