Step sequencer tremelo?

[Gumby212]

Would anyone be able to point me in the right direction on building a step sequencer tremelo? I know nothing about step sequencers, but ive built a few optical tremelos, thoni am fairly novice at understanding the technical side of all this. But i was very intrigued when i saw the zvex tremorama and would love to play with a circuit like that, tho i cant find a schematic online. Surely theres two schematics i can lump together right? Doesnt seem like too crazy of a project to tackle. Any help would be much appreciated. Thanks!

[nocentelli]

Which optical trems have you made?

The sequencer part of the original Zvex seek pedals used a 4017 chip. This chip takes a clock signal from an LFO and uses it to sequentially output a voltage from ten pins, though you can switch the "last" pin in your desired sequence to a reset pin to give 2/3/4/6/8/whatever steps.

You would need to use separate potentiometers connected to each output pin to set the output signal level at each step and sum the outputs to send a control voltage to a single LED which would form half of the vactrol used as the control element in your tremelo circuit's audio path.

There is a posited schematic for the Zvex seek trem at madbean's page (although the posted schematic is slightly difficult to read) which is based on the madbean "digdug" circuit, which is itself based on zvex's seek wah, and also has a pseudo-random option on a switch. The seek wah is just a 4017 sequencer hooked up to a colorsound inductorless wah circuit, and is better researched+documented on the Internet than zvex's tremelo offerings

Alternatively, if you search for "baby 8" you will find lots of schematics for sequencer circuits based on the 4017, and you can experiment with hooking them up via an LED to any optical trem circuit you are familiar with in the manner described above.

[PRR]

ARP had a sequencer in the 2500 mainframe synth, circa 1971. Crazy. I have not looked at it in many decades. Plans:
http://www.guitarfool.com/ARP2500/1027.html

Not sure why it does not use a 4017; I don't recognize the counter chip/module they use. It has a ton of buffering after the counter (no LEDs, greedy incandescent step lamps). But then three columns of ten 10k pots, 10k mix resistors, and an active summer (plus inverse). Complicated "clock", cuz oscillators were a big thing at ARP.

[Gumby212]

The tremelo i built was one by grind customs. And i just built the layout straight to some perf board, so i didnt get as familiar with the circuit had i laid it out on a breadboard. Thanks for the info! Ill take it and see what i cant come up with. Im sure ill have many questions to follow

[cnspedalbuilder]

Try the madbean DigDug project. I dk if he makes the PCBs anymore but schematics ets should be available and there's someone in their forum (haberdasher) who will fab out of print PCBs for you.

https://www.youtube.com/watch?v=CsP5CAmRdC4

[nocentelli]

Not online anymore that I can find

[Ripthorn]

You could do this with a microcontroller and analog multiplexer pretty easily, if you know how to use the microcontrollers. Other than that, the dig dug is the only one I know of. Check the madbean archive.

[nocentelli]

Other than that, the dig dug is the only one I know of. Check the madbean archive.

Not online anymore that I can find

[bluebunny]

Not online anymore that I can find

http://www.madbeanpedals.com/projects/archives/TapTempo/DigDug.zip

[Gumby212]

Thanks for all the tips guys!