Layout for Thomas Henry's LM VCO

softfin · Last edited by softfin on Thu Nov 08, 2007 4:33 pm; edited 1 time in total

Here's a layout for Thomas Henry's LM VCO.
The schematic can be found from his book An Analog Synthesizer For the 21th Century.

This is my most complex layout this far, so I can't promise with 100% certainty that it would be free of errors, but I've checked it various times and everything should be ok. I have also built it and verified it works.

C10 is off board and connected directly to the AC/DC switch.

Thanks to Thomas Henry and Magic Smoke Electronics for allowing me to post this, also thanks to Coriolis and Tim Servo for improvement suggestions.

LM_VCO.pdf

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LM_VCO.pdf

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xpmtl · Joined: Aug 10, 2007 Posts: 162 Location: Brussels, Belgium

Pin 16 of IC 1 is not connected to anything. Shouldn't it be tied to +15v via a 56K resistor?

softfin · Posted: Thu Nov 08, 2007 4:33 pm Post subject:

Thanks for pointing that out!
It seems I accidentally deleted R30 during my last modification of the layout. It's now corrected Smile

I also separated the pcb and overlay to two pages and improved the quality of the pdf.

forbin · Posted: Thu Jan 29, 2009 5:57 am Post subject:

Thanks for the layout! Worked well...
http://forbinthesynthesizer.blogspot.com/

softfin · Posted: Thu Jan 29, 2009 10:16 am Post subject:

CJ Miller · Joined: Jan 07, 2007 Posts: 368 Location: 127.0.0.1

This VCO is very much like the first useful ones I made, but mine were only tri and square. I had made dozens of 555-based oscillators and also used those as linear VCOs. But my layout skills were so poor that my perfboard tries at better VCOs never worked - except as AM radios! I had never soldered any projects bigger than a couple of 555s and I was determined to make an ASM-1 VCO. This was before I had internet to ask anybody, eventually I did it like two years later.

I learned about the 13600 and thought that it looked like one of the most useful synth chips ever... I built a synth out of 13600 VCOs, VCFs, and VCAs. I never enclosed it, the boards just sat on the table. I only got around to experimenting with envelopes around when I moved and put it away, about 1999.

It's making me a nostalgic fool, but these are cool VCOs. Cheap, easy, and they sound great. Mine didn't track so well on the high end, but I was amazed that it even worked. They kept me from throwing in the DIY towel. Also, if you look at the 13600/13700 datasheet, you'll see that this is easily adapted to a quadrature VCO.

adambee7 · Joined: Apr 04, 2009 Posts: 420 Location: united kingdom

Could you reupload the PDF. I've tried downloading it but it seems to be corrupted.

Cheers
adam

Junk Rhythm · Joined: Jan 07, 2008 Posts: 81 Location: San Francisco, CA

adambee7 · Joined: Apr 04, 2009 Posts: 420 Location: united kingdom

Tried to dowload again but says file damaged or corrupted. I have updated acrobat but still computer says no. will try it on my mates pc later.

fonik · Posted: Tue May 26, 2009 5:28 am Post subject:

Tim Servo · Posted: Wed Jun 03, 2009 11:56 am Post subject:

Tried with Acrobat 5, and could not open the file (errors). Tried with Acrobat 8 and it opened no problem!

Tim (definitely NOT an acrobat) Servo