| Author |
[IN STOCK] L-1 Basic VCO. Eurorack. [Mouser cart p.4] |
| L-1 |
http://l-1.su/BasicVCO.html
Finally I had time to work on the VCO. I finished the second prototype and prepared docs for ordering a final prototype.
This is basic VCO because has only basic functions.
Triangle core with sync possibility based on the THAT2180 and OPA2604 chips. Regular TL07* opamp doesn't work here because of high wave amplitude. Limiting wave with diodes as were suggested gives problem with sync. So, only OPA2604 in the core.
VCO range is from 8 Hz to 14 kHz. VCO/LFO switch between timing capacitors. I used 100p and 10n 1% polystyrenes. So LFO range is 100 times slower than VCO.
No expo converter here because THAT2180 has expo responce. CV circuit is tempereture compensated with two 2K tempco resistors.
I used BCM847BC matched pair for sinewave circuit.
I used LM4040 precise voltage source for offset voltages to minimize pitch flow. I tested during 4 hours - pitch was stable in range +- one cent.
I installed Schmitt trigger on the sync input. So any wave is good for sync.
I was able to achieve cent-by-cent tracking as on the first prototype.
The VCO - left board the core, right board - saw, sine, PWM circuits:
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| djpasica |
why 
i think there is a lot of basic modules (osc)
IMHO
if it will not cost  |
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| andrewF |
| djpasica wrote: | why
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The joy & satisfaction of DIYing his own VCO and seeing it work  |
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| L-1 |
| djpasica wrote: | why
i think there is a lot of basic modules (osc)
IMHO
if it will not cost |
What for example? For DIY Euro, not digital, without timers or logic. Classic analog design.
1. 258J from Thonk.
2...  |
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| Randy |
I could see this being handy for smaller systems or adding polyphony. Make it 4hp and I'll buy it!
Randy |
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| andrewF |
| L-1 wrote: | | djpasica wrote: | why
i think there is a lot of basic modules (osc)
IMHO
if it will not cost |
What for example? For DIY Euro, not digital, without timers or logic. Classic analog design.
1. 258J from Thonk.
2... |
2... this one?  |
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| CJ Miller |
| This seems to be an interesting design! I hope I can buy a few boards eventually. |
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| L-1 |
Yes andrewF.
The second reason why I make this - it's local musicians. They require from me a complete system. |
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| andrewF |
| L-1 wrote: | Yes andrewF.
The second reason why I make this - it's local musicians. They require from me a complete system. |
Pretty lucky DIYers in your town 8_) .
the locals here in P-town have to endure my half-assed insanity  |
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| livefreela |
| i would frame that proto photograph for my wall EDIT now it's my computer desktop. awesome. l-1, way to be man, way to be! |
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| Reality Checkpoint |
Well I very much like it and applaud the classic analog design.
And I will no doubt end up with one or two in my system. |
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| bkbirge |
| andrewF wrote: | | L-1 wrote: | Yes andrewF.
The second reason why I make this - it's local musicians. They require from me a complete system. |
Pretty lucky DIYers in your town 8_) .
the locals here in P-town have to endure my half-assed insanity |
Don't sell yourself short man, there's nothing half-assed about your insanity.
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| cane creek |
I'm in for one of these  |
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| horstronic |
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| makers |
| I would also like to build two of these! |
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| Barcode |
| Single PCB? No wiring? Awesome in my book! |
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| stereonoss |
| L-1 wrote: | Yes andrewF.
The second reason why I make this - it's local musicians. They require from me a complete system. |
+1
I have Quad VCA/Mixer and Tube VCA from you ) it sounds perfectly and i will buy system complete from L-1 Corporation ))) |
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| stereonoss |
| L-1 wrote: | Yes andrewF.
The second reason why I make this - it's local musicians. They require from me a complete system. |
+1
I have Quad VCA/Mixer and Tube VCA from you ) it sounds perfectly and i will buy system complete from L-1 Corporation ))) |
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| euromorcego |
| Quote: | | They require from me a complete system. |
As do we!  |
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| Stides |
| Looks nice to me. Reasonable size to feature ratio, and seems to have a minimal component count. Always comes to price and availability, but your stuff always is reasonable. |
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| synthcube |
| Can't wait for this one!, |
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| sonicwarrior |
Would have been nice to an attenuator for the PWM input. I always need an attenuator plus offset there.
FM is linear I hope?
Only 3 trimmers look like fun to calibrate. I'm always intimidated by the many trimmers on most VCO PCBs. 
Edit: Does it run with +/- 15 V? Would be fun to squeeze this into a single width MU panel although it would mean panel wiring. |
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| L-1 |
| sonicwarrior wrote: | Would have been nice to an attenuator for the PWM input. I always need an attenuator plus offset there.
FM is linear I hope?
Only 3 trimmers look like fun to calibrate. I'm always intimidated by the many trimmers on most VCO PCBs.
Edit: Does it run with +/- 15 V? Would be fun to squeeze this into a single width MU panel although it would mean panel wiring. |
No place for PWM attenuator sorry.
No linear FM, only exp. 2180 chip has exp response, and needs another matched transistors pair for linear.
About 15V. It can I think but some resistors changes will need. There is 10V source for offset voltages.
I plan to make more advanced dual osc later. I will include there lin FM and many other possibilities. |
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| L-1 |
| synthcube wrote: | | Can't wait for this one!, |
I already prdered boards for a prototype! |
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| L-1 |
| Quote: | | Only 3 trimmers look like fun to calibrate. I'm always intimidated by the many trimmers on most VCO PCBs. oops |
Really I added fourth. Will be:
- v/oct
- offset
- saw symmetry
- sine symmetry |
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