External sync of hardware/555 timer IC

[the19thbear]

Hi. I have an Elka wilgamat III
Im trying to sync it up via an external sync ( a metronome from my DA on my pc). But it wont work.. this works fine on my juno 6.

Could anyone tell me what i need to do to get it working?
As you can see the 555 timer is feeding a "sync out" and the CPU that sends pulses out to everything.(drums, arpeggio etc)

I tried inserting the metronome signal on the pin that says 17,5 on the 410CST1474(the top circuit), because it leads directly to the CPU coming from the 555 IC (IC 7) and also on right after IC's output (the sync signal comes from the 555 and goes into IC 9 and out)

Thanks:)


If i want to go the midi way could i then use this?
http://m.bareille.free.fr/mc628/mc628.html

[jksuperstar]

Got a probe to see what it does by itself? Or it looks like clk out is 5v at best, so maybe you can look at it with a protected audio input to see what it's up to?

[the19thbear]

I havent got a freq counter (i havent recorded the signal, otherwise i could find out that way). But my guess is that its about 30hz +/- whatever when you tune the tempo pot. - that will of course NOT work, since the metronome beat is nowhere near 30 hz
I cant remember exactly but i think the signal was about 2.2 volts and it went up a couple of 0.X's when i turned up the tempo (but im gessing the rise in voltage doesnt matter, it should only be the freq of the clock that matters..)

Do you think this would work?
http://m.bareille.free.fr/mc628/mc628.html

thanks!

[jksuperstar]

Since it has a clock output jack, I'd expect it to be a lot like DIN Sync, or similar.

If you have an available audio output, there's no reason you couldn't send pulses out and into that device. In fact, it'd be easy to add a switch to disconnect the 555timer connection at the RATE/EQUAL switch (labelled F/3), and allow that clock out jack to become a clock IN jack, instead. I can't guarantee it's all perfectly safe & ok, but I don't really see a reason why not. I'm not sure what chip 27 is, but it must be a buffer/inverter or something like it? I think R1/10K would keep you pretty safe from damage to your audio, especially if you use an AC coupled single-ended output.

After the above modification, drive a PWM type OSC/LFO to your audio output into that clock out jack. (or use an audio track in your DAW, or a wavetable osc). Here's the old DIN sync signalling as a reference. Make sure it is not a +/- signal, but positive only. If that doesn't work, invert the signal to the output.
http://en.wikipedia.org/wiki/DIN_sync

And this will probably help:
http://www.rv0.be/sudc.html

Just try to match 24ppqn for a given BPM, pulse width of and increase the volume until the unit begins to trigger

If that works, your MIDI to sync would also work. But I'd expect tighter timing possible from an audio pulse!

[the19thbear]

Thanks man!!:)

[the19thbear]

You mentioned that it has to be + only what i measured out from the "17,5" cable was +2.something volts. The output from my soundcard will be +/- - i guess i could somehow offset it only to be on the positive side.. how would you go about doing that? i guess i might be able to do it in mod3.

hmmm. couldnt get it to trigger with a normal +/- signal (of course)... even with the software solutions that you linked to. They did however work to sync my jupiter 4! so thats cool:) I even tried amplifying the sync signal via an external headphone amp before sending it to the elka.

Any hints are welcome and thansk ALOT for your help already

[jksuperstar]

I'll have to give it some thought. In the mean time, there's also SilentWay (from expert Sleepers). Which tries to use audio outs as CV control.

[dawman]

Espert Sleepers Silentway Suite doesn't try, it works.
Stick in Reaper and use the audio inputs of Modular and the audiorate modulation difference can be heard immediately. You'll need a larger patch for polyphony...

[the19thbear]

the thing im concerned about is ac/dc - constant plus volt/ swinging between plus and minus.
I would need a ac to dc converter somehow.. But i'll try expert sleepers and see if it somehow works (tried it before in reaper and couldnt get it to work - maybe because of the A16 ultra?

[jksuperstar]

What chips are 9 (inverter driving from 555 to the clock out), 27, and 28 (near the clock out)? Hex Drivers or Inverters? CMOS or TTL?

That might help know what it is sensitive to and what is sufficient to trigger it.

[the19thbear]

Update!
I actually got it working using expert sleepers and just a simple LFO signal.

I was having small problems with the timing sometimes... but who knows what that might have been.
I took the signal from DA conv. out into headphone preamp. then I disconnected 17,5 and connected connected F/3 to the cable coming from the headphone amp. Turned it up and it started triggering. I had to fiddle around with the waveform/offset/headphone gain before i could get a non-swing rythm from the elka (its supposed not to swing).
If i set the LFO to sync to DAW temp, then the beat is WAY too slow - its like 5 seconds between each hit (on a 180bpm tempo in the daw). The only way i could get it to do anything near a decent tempo was to set the LFO to free mode and turning it manually..So my question is, will the midi beat clock convert that i linked to in my first post work?? Will it spit out pulses fast enough?

Some other day when i have time, i might have to listen to the clock generated in the elka and the clock generated by expert sleepers and compare them to se if they are in the same freq area - otherwise i might need to tweek the waveform furter to do double trigging (if thats possible).
THANKS for all your help guys