I'm continuing to explore the tap looper concept and have come up with this schematic for a variable length, tap programmable looper (click the above image to open it in a larger window). The great thing about being able to vary the length of the register is that you can then create sequences in alternate time signatures as well as 4/4. This variable shift register IC the MC14557 can be programmed to create any register length up to 64 bits..in the video below I am using 48 bits to create a 2 bar 3/4 time signature using 8 bits per 1/4 note resolution. I am pleased with this design (mostly as really it is the first thing I have designed from scratch based off the info in the datasheet) however it has the same shortcoming as the 4031 based tap looper- that it only maintains resolution at faster tempo's. I plan to experiment with cascading 2 of these registers, doubling the length of any given loop so that I could create 4 bar sequences at higher tempos and 2 bar sequences at lower tempos whilst still maintaining enough resolution.
Feel free to use this schematic however you like but give me a credit if you can :)
3 comments:
Can you run any type of audio into this, like e output of a drum machine, or synth, instead of CMOS synths?
I love the blog BTW, keep up the good work!
Cheers,
Matt
Cheers for the comment and compliments sir. You can only do CMOS stuff with this actual looping shift register, however the shift register could control an envelope generator that could be beeing fed audio...I'll give this a try at some point when I get some time.
Thanks for reading the blog.
You could use a pot connected to an a/d converter to select the length of the register to fun effect. What happens to the values in the register if you were to shorten the loop then make it longer again? do the previous values persist? this could be a fun project!
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