I made a start on converting Polykits Pico DCO into cosmo format. There is goign to be a main board with the ribbon connector that can go either to a 1/4" Jack board or on to the ADSR.
1st part was to re-lay the main PCB…
few final tweaks and it’s ready ( version, credits, graphis, etc )
Next up the front panel.
Front Panel Main
Front Panel Jack Board.
Cheers to Poly for sharing his designs.
Nearly missed this… Added a midi input tell tale and schmits to clean up the edge of the signal.
1st fix on the main front panel. needed to do the Jack board one to get the graphics ligned up
On a Role… FP done for the output module.
Now just the boring stuff of checking , routing, fills.
January 27, 2023, 4:18pm
Looks amazing - are you going to put detune and stacking controls on the front panel too?
Might be less useful in a modular build, but I use them all the time. It’s great to be able to switch to mono and stack up your voices.
January 28, 2023, 1:22pm
Wow, looks awesome! I’m definitely going to build one. In newer versions there is also a FM input. Maybe you can add that as well. Thanks for all the effort
@jkb , is that new in the last few weeks? the repository was only cloned recently.
Easy enough to add, although space is getting short. May have to have a side module control board that could also have stack and de-tune
The jack board has in/out connectors with the out being Normaled from the Jacks. Making it up as I go along
January 28, 2023, 1:27pm
No, it has been contributed some time ago and is in the end just using one of the ADCs for frequency modulation.
@savt22 , there’s a header on the board to connect to unused pins on the PICO.
Not really looked at the code but I assume the header is for “Future Use” and as such I could do other things with it on a side module. So I guess yes there is potential for stacking and detune.
Ahh I see the functions are already there, should have read further through the page on the github.
I think I am out of space on the main board. and it’s ready to print. Will have a think tomorrow.
January 28, 2023, 9:38pm
I think it’s fine. You’re bringing out all unused pins of the Pico so it can be easily added.
January 29, 2023, 2:07pm
As I mentioned it’s likely much less useful for modular, but I use the stacked and mono options all the time. 6 voices slightly detuned as a mono voice sounds so fat…
I built the pico dco though as a self-contained polysynth though.
@jkb the code on the FM input mentions a hardware fix for a voltage offset… Could you expand on this? the next parts willl be the ADSR, VCA and aditionla controls so would be good to understand the FM stage…
It’s been sent of to JLC, with some other projects. because of the weight the postage is with Fedex rather than China Post, so it could be here next week.
Made a start on the ADSR, removing two of the 8 chanels and making revisions mostly to fit with my overall plan.
I expect the boards, along with some others I slapped in the order may be here this week… Gives me a chance to finalise the ADSR v1 and get it in the pipeline if the VCDO works…
I like the idea of the LMNC 1222 ( or more correctly the analog vco ) but it’s been a barrier to me getting any consistent notes out of it ( or my own clone ) so hopefully the DCO will give me hope that I can manage to knock out a hardcore banging twinkle twinkle little star in tune
It’s so near, yet so far… Not even in the country yet
At local FedEx facility, Package not delivered/not attempted,GRETNA GREEN, DG, GB
At local FedEx facility,GRETNA GREEN, DG, GB
Delay, Package at station, arrived after courier dispatch.,GRETNA GREEN, DG, GB
Progressing ok with the build,
Found an unconnected ground from two power leds,
After finding out that ( See the Litany thread
A litany of dumbassery - #939 by twinturbo )
My brain was disengaged when using a 74LS14 on a 3.3V design
even if it was correct having no power at all connected to the chip was a sure fire failure.
I bodged the power to the 3.3V rail and ordreed some 74HC14 Hex Inveretes instead.
Stage one complete, I can see the midi comming to the board
I think everything else is populated apart from the IDC boxes for the output.
I have added the details of the input circuit to a GIT repository
Staggeringly it seems to work , i did spend the morning bashing my brains wondering why it would only play every 6th note, i did only have one output mixed though.
It dawned on me eventually that the code was always assigning the next note output in sequence rather than starting from zero even if it was note off.
The output jacks have actually proved useful , even if i did make the jack board with 0 at the bottom and 5 at the top.
Into the mini mixer
And it works but theres background noise , sounds Digital .