CV Input Rehash

edited November 2010 in WTPA1 Mods
After viewing this topic ( and searching, I'm still not clear whether CV control of the WTPA's oscillator (via "sync") is possible. From what I glean, it is possible, but you have to go through some hoops to get it to work well.
Is there any way to get the WTPA to respond to control voltages within a common modular synth's range (+/-5V or even 10V...something like that)?
I apologize if I'm rehashing this discussion.
SMRL or Altitude, were you able to do this?


  • Hey d,
    The current WTPA uses an RC oscillator, so it doesn't take a direct CV in, but it will take a square wave via the sync input. So you can feed your CV to a VCO and then feed that to WTPA.
    You may need want to disable the main clock if you're gonna do that.

    WTPA2, whenever it sees the light of day, has a built in VCO so it can take CV inputs natively.

    Hope this helps,
  • Yeah, that totally helps! I get it now.
    As I have recently gotten into modular synths, I'm very excited to try this. (I only have 3 modules so far.)
    Can't wait to interface with the WTPA2. (Eurorack format?!?! Haha...probably not: you said that that pcb is going to be bigger and it'll have a daughter board as well. Still...there is a market for this sort of thing.)
  • You aren't the first person to ask. There are a lot of compelling reasons to make a smaller WTPA board, but it couldn't be a kit (the parts would have to be SMT). I've thought about it...
  • edited November 2010
    Not sure how worth it it would be, but you could provide a kit with a stuffed SMT PCB and a panel. That leaves the user to find jacks, stick em on the panel, and wire them to the board, and saves you the assembly time. I would definitely buy one.
  • True. It might make sense to sell _just_ the populated board, that way a user could stick it in whatever enclosure they wanted (eurorack, pedal, etc) and use whatever controls they wanted.
    Otherwise, it'd make sense to just sell as a finished unit. But that's still a ways away.
  • I am so afraid to feed a square wave from my +/-5V oscillator into the WTPA's sync input... but i think D4 and D5 are there to protect the Atmega from overload and negative currents, isn't it? I am thinking about adding a jack for feeding signals from my modular. It could be a switched jack so there would be no need to add a switch to disable the internal osc.. just thinking out loud!!
  • At 0-5v you should be fine, but yes, those diodes should save you from overvoltages. A switched jack might help you get a cleaner sync.
Sign In or Register to comment.