it was aimed to fit onto one PCB and a small case
MIDI, dual LFOs dedicated to oscillator PWM, the Power Supply That Does Not Suck
and it does sound already – like this: http://www.cs80.com/crowminius/CrowminiusDemo01.mp3
and yes, it’s made to go around, so you might save $100 for the board and here’s the data (quoted):
- The circuit board is 8.5″ x 11″ (216mm x 280mm), the size of the DuinoKit Essentials PC board the aluminum case of which settled the form factor goal for the Crowminius project.
- The green things are some 3D-printed shelf clips I made that serve as makeshift pitch/mod levers. I will print better ones meant for this.
- There are three LFO LEDs, two are behind the PWM pots (top middle), the 3rd shows the rate of the control osc. and is over by the pitch/mod wheel pots.
- The vactrol/LDR is for MIDI modwheel action, which is kind of experimental at the moment.
- The A440 reference is not a Wein bridge sine oscillator, but rather is a DDS table-lookup PWM sine tone generated on the MIDI microcontroller.
- There will be USB MIDI, once I figure out how to do it. I rigged the hardware as per the V-USB spec but I am not a C programmer by trade. But, eventually.
- The power supply will run on a single 12VAC, 250mA wall transformer. The power supply that does not suck mode involves the use of two 12VAC wall transformers so as to provide full-wave rectification.
- The DAC is scaled to provide 5 octaves, F1 to F6 over a 4.096-Volt range. The DAC’s 2nd channel will operate the filter cutoff for assignable key velocity or whatever.
- I did not use ua726s as they are a pain to get and the thought of exposed parts heated to 80C meant someone would get burned. LM3046s are fine; there is a tempco resistor under the three arrays for the VCOs.
- The filter resonance pot is in fact a 50K reverse-log type, but I provided for using a linear pot+resistor to cheeseball it.
- Yes I will be offering bare boards. They will be $100.00. I have to correct a few cosmetic issues (mostly reversed knob and switch actions) but every part came from Digikey, Jameco, Mouser or Small Bear.
Forum: Crowminius (deutsch)