The Tap Tempo Tremolo is the first and only DIY trem project that allows you to tap in the rhythm with a footswitch. This capability makes it easy to synchronize a rhythmic trem to the beat of your song. Besides that, it’s a great-sounding trem, and certainly the most versatile DIY trem out there.

The TTT covers territory from smooth and deep “throb”, through the classic “repeat percussion” effects to hard chopping square wave. It features 8 different waveforms, and the wave distort function allows you to change the character of each wave drastically.

This PCB was designed for the original TAPLFO chip, but can be used with the newer version with the following changes:

1) Don’t solder in the crystal or the two 22pF caps next to it. The new chip doesn’t require a crystal.

2) Don’t solder in the 10K on the tap tempo switch input (next to the 22pF caps you just ignored)

3) Don’t solder in the 10K on the EXP switch input (furthest left of the three below where it says WAVE D|STORT). This is for the “Next Multiplier” switch, but this feature doesn’t appear on the new chip.

In addition, there are two new features:

1) If you add a SPST toggle switch between the two pads for the 22pF cap connected to pin 3 (e.g. pin3 connected to ground), you can select a new set of waveforms.

2) If you have problems with ticking, you can ground pin6. This activates the waveform smoothing filter giving all waveforms a 20msec rise/fall time. This should help reduce ticking noises.

The TTT uses a digital microcontroller to do the tap tempo and create the waveforms. It then uses an optocoupler to control volume. The audio path remains analog all the way through, while giving you the complexity and versatility of digital control.

The TTT’s digital LFO is designed by Tom Wiltshire.

Click here to download the Tap Tempo Tremolo build PDF. This file includes wiring diagrams, schematic, bill of materials, and details on adding useful mods.

Here’s a thread with questions, answers, build reports and photos of the TTT.

Here's an alternate way to wire the bypass switch,  which grounds the LFO signal when the effect is bypassed.