exp. pedal? how to not accidentally blow up my aleph

  • So I want to connect an expression pedal to the CV on the aleph (i think this was vaguely suggested as possible in some pre-release discussions)
    Before I plug it in i just want to check my thinking. I have a pedal with a trs jack. So I've soldered two mono 3.5mm cables into a stereo socket connector (one wired to tip, one wired to ring, then both grounds connected to the sleeve)
    In theory I plug one of my 3.5s into a CV output and the other to a CV input and the pedal should allow me to vary the voltage?
    Any chance I'm going to destroy the circuits on the aleph? (it's a Roland ev5 pedal, manual gives no clues as to its electrical stats)
    Thanks in advance for any tips! (or warnings :))

  • i've been wondering about this as well

  • i'm 95% confident you'll be fine. that is, if the pedal is just a potentiometer wired to the stereo jack (i assume so?) the worst that could happen is the full output voltage going to the input voltage (that's fine) or the output being shorted to ground.

    there's a current limiter on the cv outputs so i don't think it's possible to blow them up by drawing too much current. the inputs have voltage clamps so they can't go outside the prescribed range.

    the pedal is passive right? no power? if that's the case then i'd say go for it!

  • seems right to me

  • hmm.. well nothing happening at the moment.. if i set CV-IN/ENABLE to 1 and connect CV-IN/VAL0 to a BIGNUM I instantly get 4095 displayed on the screen. but can't get it to change no matter what the CV0 output value or the expression pedal is set to.
    going to check my wiring again :(
    anything else i should check?

  • as a first test to make sure the CV-IN is working correctly, connect a cable from cv_out0 directly to CV-IN0 and you should see the value at CV-IN follow cv_out.

    if it's an unpowered pedal, i can't see how it would report a higher voltage than you're sending out of cv_out. do you have a multimeter to test voltages?

  • Test the pedal and cables with a mult for resistance when sweeped?

  • @galapagoose CV-IN0 sends 4095 the moment it is enabled (and connected to a BIGNUM) regardless of whether anything is plugged into the socket or not. Is this normal behaviour for the CV in sockets (I don't have a 3.5mm patch cable to hand to test the direct route, will pick one up today).. maybe someone else could confirm?

  • ok.. so i've connected CV0 output directly to CV0 input with a 3.5mm cable (it's a stereo on, i.e. trs, would that be causing the problem.. if so scrap the next bit until i find a mono jack)
    and nothing comes through. if i connect CV-IN/VAL0 to control hz1 it just stays at 20.4534, but CV0 parameter is constantly varying.
    Is this likely to be a software or hardware problem? Can someone confirm for me that they've actually used the CV inputs successfully?

  • just tried it with a mono cable and still no luck :(

  • hardware. email info@monome.org . should have been tested with a loopback before shipping. did you try any other channels?

  • attached is the cvtest screen. use 0.4.2

    it works fine here. if it's not working for you, e-mail me and we'll do a repair.

  • on the github it goes 0.3.1 then straight to 0.4.4,
    where can i get 0.4.2 ?
    thanks

  • (tried with 0.4.4. .. totally fubar, doesn't work, and if i'm on the INPUTS page and I scroll down none of the parameter names display correctly, just a few @ symbols and then it freezes the device)

  • https://github.com/tehn/aleph/releases/tag/aleph-140402

    this says 0.4.1, but 0.4.2 is in the zip, sorry for the confusion

  • hold on, are you talking about the BEES version or the Waves version?
    That link takes me to bees 0.5.2?
    should I be running the test scene with BEES 0.5.2 and WAVES 0.4.2 ?

  • ack, sorry, you're correct. i'm confused. the scene was made running a clean install from the github linked

  • edited the release name to reflect waves-0.4.2. this was a minor update that fixes waveshape slew processing and shouldn't affect CV.

    in general: these version numbers use semantic versioning. that means you can assume that if only the last number changed, compatibility isn't broken. if the second number changes, compatibility is broken one way or another, and one must check the changelog and release notes.