Posted: Fri Jan 06, 2017 4:56 am Post subject:
2017 Build Photos! Subject description: Show us what you have been building
I was hoping to finish this during the holidaze, but didn't end up having time due to visiting relatives.
CLK-OSC: clock oscillator module for a collective synth at the Eastern Bloc soundLab in Montreal... Some basic square wave oscillators: 2 with inverted outs as well, 1 normal, and one with mark & space control (i.e. adjustable duty cycle), all with 2 frequency ranges.
The LEDs are sanded flush with the wooden panel. It's a bit of a mess on the back... it was my first panel rather than a box, and probably it would have been better to mount the panel perpendicular. Oh, well.
.:James:.
Edit: replaced verso photo with updated circuit.
CLK_OSC recto sq768.jpg
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CLK-OSC module panel (front)
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CLK_OSC module - verso4-800.jpg
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CLK-OSC module (back)
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Last edited by RingMad on Sun Jan 08, 2017 8:11 am; edited 1 time in total
Does the duty cycle control work by using diodes to create separate controls for rise/fall times ?
Yes, exactly. And in this case I used LEDs for the diodes, which will blink in some cases. When I tried using LEDs with a higher forward voltage, it didn't work. Probably using 1N4148's is best, and driving separate indicator LEDs somehow, but I went with a basic circuit I've used before.
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
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Posted: Fri Jan 06, 2017 8:54 am Post subject:
ah so that's why I wasn't able to spot any diodes on the PCB. Makes sense about the forward voltage, it will probably depend a bit on the supply
voltage but if it is too large the voltage over the capacitor will never get high enough to go beyond the treshold level of the schmitt trigger inverters. _________________ "My perf, it's full of holes!" http://phobos.000space.com/ SoundCloudBandCampMixCloudStickney SynthyardsCaptain ColliderTwitchYouTube
Joined: Feb 16, 2007 Posts: 347 Location: Manchester UK
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Posted: Sat Jan 07, 2017 12:33 am Post subject:
I've finally finished it - Sparta Synthesizer, based on the ARP Odyssey with an extra VCO (Mono/3 VCO Paraphonic), Patch Points and Aftertouch/Modulation routing. I cheated a bit by using a CME Xkey 37 - I couldn't face all those J-Wires again.
I think I'm done with DIY now - I have no more room left and I need to reclaim my sanity.
ah so that's why I wasn't able to spot any diodes on the PCB. Makes sense about the forward voltage, it will probably depend a bit on the supply
voltage but if it is too large the voltage over the capacitor will never get high enough to go beyond the treshold level of the schmitt trigger inverters.
Re mark & space / duty cycle control: Since I still had it on the breadboard, I tried using 1N4148's for the diodes and simple transistor drivers for the LEDs, and it works much better. The output wave is cleaner (before, using LEDs, it wouldn't go all the way back down to 0V). With the drivers, the LEDs are good and bright. I had a little bit of space left on the perfboard, so I made the changes... I updated the photo above, so you might spot the diodes now .
Feel a bit reminded of old Serge modules... Can i ask what modules it contain?
Here's a list.
Panel 1
FlexWave Complex Dual VCO
Dual VCA (my version of the Mike Sims style pre-distortion VCA)
Dynamix (this contains two resonant LPGs, two linear slope generators, stereo output mixer, analog OR mixer to mix slopes)
Panel 2
DXOR (Schottky diode XOR circuit with logic and audio outputs plus a voltage controlled integrator)
DivisiClock (VC clock with /2 /3 and /4 divisions)
Bit Station (shift register based pseudo random CV, digital noise, white noise module)
MicroState Filter (state variable filter with two variable FM inputs, "Ping" input, etc.)
CV Processor/Offset Generator
Audio Mixer
Panel 3
UltraFlop 08 (sequencer with up, down, and pingpong counting, individual gate outputs, a combined gate output (post switches)
Two manual gate and manual DC voltage sections.
nice synth and a nice photo J3RK, would love to see a bit more of it. Love the arcade buttons
I still have a couple of those laying around here which I should use someday, hmm actually I might
have an idea. Thanks for reminding me.
I love arcade buttons. I actually occasionally build arcade controllers for MAME use, so I have these around sometimes.
I'll post a couple more pics as soon as I get a chance.
They look to be 5u, however pictures sometimes deceive.
I like how you mounted your boards.
The older I get the more I appreciate 5U, big knobs and everything out in the open. Ideally there will be normaling of signals coming and going on D connectors with a basic patch hardwired.
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