Presenting: Crowminius

[Troubleshooter]

Hi,
sorry to bother but is there any chance to get in Europe (Italy) this opto coupler ?

PC900V0NSZXF

Even a replacement would be fine if there's any...

Thx

https://www.conrad.nl/nl/optocoupler-fo ... 84098.html

or EBAY like I did

[colorbars]

For anyone who's interested I'm selling my crowminius from the first run of boards here for roughly what it cost me to build...

viewtopic.php?t=187530

Hope it's ok to post this here, if not please delete

[Godric]

I carried this error forward onto my panel and didn't notice it until after fabrication - sigh!

To answer this question this was me forgetting to change the panel graphic to the reverse saw on osc3. This is only on a few of my early panels.

Crow
/**/

A question, some half of the crowminius fronts I have seen have the reverse saw on OSC3 the other half have the 3 times the same saw/tri mixed waveform. Wich one should I engrave for the rev.3 board?

[stringsthings]

I'm at the stage where I'm doing the mass of offboard wiring for my Crowminius build. I've got a question for the people who have finished their build ( or almost finished ). Did you need to use shielded wire for any of the offboard pots, switches, or jacks?

I can see the possiblility of shielding the wires to the outputs ( jack, pot, switch ). But if I don't have to shield, I won't bother. Doing all the pots and switches and jacks is enough of a headache.

[Troubleshooter]

I am about 50% done in wiring mine and took the risk to not shield anything. I will put my AC transformer in an external box however.
I never shielded anything in my DIY stuff except for a few cases (tube
guitar amps, backlit LCD displays close to audio chains, etc...). Since my cabeling is longer than usual also I don't really know what to expect. Fingers crossed.

I'm at the stage where I'm doing the mass of offboard wiring for my Crowminius build. I've got a question for the people who have finished their build ( or almost finished ). Did you need to use shielded wire for any of the offboard pots, switches, or jacks?

I can see the possiblility of shielding the wires to the outputs ( jack, pot, switch ). But if I don't have to shield, I won't bother. Doing all the pots and switches and jacks is enough of a headache.

[JanneI]

@oldcrow:

I'm back at troubleshooting my crowminius build. Still the cv from midi/tune/pitchwheel is way out of scale:



..so I was thinking could the problem be somewhere in the cv summers (IC1?), feedback resistor value perhaps?

What I have is (pcb1.1.3):

IC1A=TL072:
R1 = 301k
R2 = 100k
R390 =
R3 = 1M24
R4 = 102k
R5 = 100k
R6 = 121k
R7 = jumper

IC1B:
R13 = 69k8
R17 = 90k9
R19 = 53k6
R21 = 49k9
R22 = jumper
R23 = 2k32

R392 = 1k
R200 = what this should be?

If these are correct what should I try next? Thanks!

[stringsthings]

JanneI, what values did you use for resistors R23, R63, R101A?

These 3 resistors are related to the tempco resistors R24/R24A, R64/R64A, R102/R102A. If you got these mixed up, it might be the cause of your problem.

[JanneI]

Sorry, I edited the list above. So
R23 = 2k32
R24 = 1k tempco smd under the c3046.

Should my R23 be 23k2 with the 1k tempco?

[JanneI]

Should my R23 be 23k2 with the 1k tempco?

Yes! I just tried with 22k (R23) resistor for VCO1 and now it's much better, so I guess that was it. Now I just need to change it to correct value for all the oscillators. Thank you!

[stringsthings]

Should my R23 be 23k2 with the 1k tempco?

Yes! I just tried with 22k (R23) resistor for VCO1 and now it's much better, so I guess that was it. Now I just need to change it to correct value for all the oscillators. Thank you!

You're very welcome. As you found out, R23, R63, R101 should be 23.2k if the tempco's are 1k.

I'm finally finishing up my build. All that's left is wiring up a couple of LEDs and calibration/tuning. My MIDI keyboard broke, so I need to order a new one. So I've been testing it with CV/Gate.

[wahee]

just wondering if there is a way to permanently set the MIDI channel on the Crowminius and OMNI off

[Troubleshooter]

I have made the first test run yesterday.

Adjusted PSU to -10,00 and +10,00

VCO's are working and tunable. However the range seems just out of reach of the trimmers. So I will have to change a resistor value. I also notice that my SAW wave is not symetrically (completely negative) and half of the amplitude of the TRI / TRAMP waves wich are symetrical. I have this in all 3 VCO's.

Noise is working

MIDI 2 CV/GATE is working

LFO LEDS are blinking

VCF/VCA seems to bee the problem child. The filter acts more like a LO-FI equalizer with limited range. It does affect the sound as a filter but doesn't have the required range (doesn't fully open or close) not by dialing the pot or contour or key track or trimming the range.
Emphasis is not working either. Moving the Emphasis knob or trimmer doesn't affect the sound at all. Also the main/headphone outputs are very very weak. The VCA however does close perfectly to silence. Balance 1 trim does reduce the "Click" sound.

Both VCA and VCF contours seem to work.

I havent tested any modulations yet.

I have built maby 20 DIY VCF's and never had one with limited range.
All tips for debugging filters are welcome since ladder filters are so hard to measure out.

All and all I am happy that it makes a sound from the first test.

[stringsthings]

Also the main/headphone outputs are very very weak.

Do you have J2 (Loudness) installed? This is a switching jack that needs to be installed ( or you can just jumper the Tip and Sleeve connections ) in order for the VCA to work.

[Troubleshooter]

Also the main/headphone outputs are very very weak.

Do you have J2 (Loudness) installed? This is a switching jack that needs to be installed ( or you can just jumper the Tip and Sleeve connections ) in order for the VCA to work.

Hi StringsThing, thanks for the tip but Yes I did. It has been mentioned a few times in this forum and I did read all 40 pages.

Do you know what peak to peak ampletudes are to be expected on the mixer bus, after VCF, hi and low output and so on? I would appreciate it if someone could make some measurements for me or even better some scope screen shots.

[Troubleshooter]

Also the main/headphone outputs are very very weak.

Do you have J2 (Loudness) installed? This is a switching jack that needs to be installed ( or you can just jumper the Tip and Sleeve connections ) in order for the VCA to work.

Hi StringsThing, thanks for the tip but Yes I did. It has been mentioned a few times in this forum and I did read all 40 pages.

Do you know what peak to peak ampletudes are to be expected on the mixer bus, after VCF, hi and low output and so on? I would appreciate it if someone could make some measurements for me or even better some scope screen shots.

Update:

Output volume and filter resonance are OK now! Found a short between 2 very close soldering pads in the filter section. Now it really sounds good to my ears.

Modulations are not working however. I can measure the modulation mix going into the resistor just before the LM13700. But the OTA doesn't output anything towards the TL072. I have rotated Q16 as shown on the silkscreen print. I'l have to keep on debugging a little more I guess.

Untill now using all unshielded cables doesn't seem to add any Humm, or signal bleed.

[stringsthings]

Modulations are not working however. I can measure the modulation mix going into the resistor just before the LM13700. But the OTA doesn't output anything towards the TL072.

Is the modulation LED working? I think it's LED 8. It's on page 2 of the schematic in the "modulation mixer" section. If the LED is working, you can rule out the circuit before that point.
If it's not working, I would feed it something from OSC 3 or the NOISE section and check around that part on page 2.

Modulation seems to depend on several parts of the circuit that feed the LM13700. To get something out of the LM13700, it needs input from both pins 14 and 16.

[Troubleshooter]

Hi,

The LED is working as expected on both noise (flickering) and OSC3 (blinking).
R359 and pin 14 receive the modulation mix. Pin 16 should pull a negative current trough Q16 and R394. Any idea what currents to expect with mod wheel up and down (measurable by voltage drop over 394)?

Kind Regards,

Gerd

Modulations are not working however. I can measure the modulation mix going into the resistor just before the LM13700. But the OTA doesn't output anything towards the TL072.

Is the modulation LED working? I think it's LED 8. It's on page 2 of the schematic in the "modulation mixer" section. If the LED is working, you can rule out the circuit before that point.
If it's not working, I would feed it something from OSC 3 or the NOISE section and check around that part on page 2.

Modulation seems to depend on several parts of the circuit that feed the LM13700. To get something out of the LM13700, it needs input from both pins 14 and 16.

[stringsthings]

Any idea what currents to expect with mod wheel up and down (measurable by voltage drop over 394)?

Mod wheel at minimum, I measure 0.029V across R394.
Mod wheel at maximum, I get 1.20V across R394.

[peAk]

Good luck getting a Modulation pot that works well with this.

Moog used a special tapered pot that's pretty much impossible to find. That, coupled with the modulation bleed through, makes going from nice smooth tones to vibrato somewhat impossible. At least it was for me. Not so bad with filter modulation but more so with pitch.

I'd love to hear from Crow or anyone else that has achieved satisfactory results. I realize that many people are using just a pot and knob for the modulation control which is going to be more extreme cause of the full rotation as with the wheel that limits it somewhat

[stringsthings]

Good luck getting a Modulation pot that works well with this.

Moog used a special tapered pot that's pretty much impossible to find. That, coupled with the modulation bleed through, makes going from nice smooth tones to vibrato somewhat impossible. At least it was for me. Not so bad with filter modulation but more so with pitch.

I'd love to hear from Crow or anyone else that has achieved satisfactory results. I realize that many people are using just a pot and knob for the modulation control which is going to be more extreme cause of the full rotation as with the wheel that limits it somewhat

Yeah, I just used a regular pot/knob for the modulation. And I did notice that the minimum modulation of pitch is pretty noticeable.

[medbot]

I agree. The modulation pot gives me about 5% useful travel and the rest is full blast. If I was doing it again I'd use a trimmer for the mod wheel, set it at max, and then have attenuator pots for VCO and VCF modulation instead of just on/off switches. That way I could easily set precise amounts for each (I hate them sharing the modulation level). Hell, if I was doing it again, I'd have separate modulation pots for each oscillator. And route the filter EG to the VCOs, and add sync, and, and, and.......

[Troubleshooter]

Any idea what currents to expect with mod wheel up and down (measurable by voltage drop over 394)?

Mod wheel at minimum, I measure 0.029V across R394.
Mod wheel at maximum, I get 1.20V across R394.

Hi thanks for the reply.
As expected my voltages don't start at zero.
The funny thing is that when i short the 5k1 resistor before the mod wheel so the mod wheel pot receives the full 10V instead of 5V the mod wheel acts correct but whth less max modulation that it should.

[Bassmanfox]

Hey just finished building this moog. Trying to either program an atmega328 or just buy one. Can anyone sell me a pre-programmed one?

I spent about 5+ hours here trying to program one using an arduino uno r3. software 1.0.6 using the setup/directions found here

https://www.arduino.cc/en/Tutorial/ArduinoToBreadboard

First off I could not load the bootloader using my Mac Tower. It is running el capitan. Even After I check all connections and setting, it just never worked, but once I changed to a windows 8 machine it uploaded as expected. I'm 99% certain I got the bootloader loaded on to the atmega328p-pu.

Then I changed the wiring per the tutorial and tried to upload Crowminius MIDICV v2 to it.
I also added the dac/midi/adafruit libraries as described. but now I get a "midi was not declared in this scope error"
Crowminius_MIDICV_v2_release.ino: In function 'void setup()':
Crowminius_MIDICV_v2_release:232: error: 'MIDI' was not declared in this scope
Crowminius_MIDICV_v2_release.ino: In function 'void loop()':
Crowminius_MIDICV_v2_release:253: error: 'MIDI' was not declared in this scope

I tried everything I can think of, but arduinos are not my specialty. Might just have to grab a midi to cv converter for now, but it'd be rad to get the midi going. Let me know your thoughts or if you can just sell me one. Thanks!

[Troubleshooter]

You will need some sort of AVR programming device like the USBtniyISP for loading the bootloader. Then you need the right libraries installed in you arduino folder.

I just used the ARVDUDESS method as discribed on the CS80 crowminius page. This also requires a programmer.

Does anyone know a way to get velocity voltage out of the V113 board? I would like to mod the code and take the Bend Trim out since i have allready the Model D style pitch bend wheel. If I could send the velocity value to pin 8 of IC 26 instead of pitch bend I could connect it to a pot and jack like the model D reissue. I love velocity sensitive filter cutoff on a model D.

Hey just finished building this moog. Trying to either program an atmega328 or just buy one. Can anyone sell me a pre-programmed one?

I spent about 5+ hours here trying to program one using an arduino uno r3. software 1.0.6 using the setup/directions found here

https://www.arduino.cc/en/Tutorial/ArduinoToBreadboard

First off I could not load the bootloader using my Mac Tower. It is running el capitan. Even After I check all connections and setting, it just never worked, but once I changed to a windows 8 machine it uploaded as expected. I'm 99% certain I got the bootloader loaded on to the atmega328p-pu.

Then I changed the wiring per the tutorial and tried to upload Crowminius MIDICV v2 to it.
I also added the dac/midi/adafruit libraries as described. but now I get a "midi was not declared in this scope error"
Crowminius_MIDICV_v2_release.ino: In function 'void setup()':
Crowminius_MIDICV_v2_release:232: error: 'MIDI' was not declared in this scope
Crowminius_MIDICV_v2_release.ino: In function 'void loop()':
Crowminius_MIDICV_v2_release:253: error: 'MIDI' was not declared in this scope

I tried everything I can think of, but arduinos are not my specialty. Might just have to grab a midi to cv converter for now, but it'd be rad to get the midi going. Let me know your thoughts or if you can just sell me one. Thanks!

[JanneI]

I did some more digging on my crowminius build. Help would be appreciated.

Everything seems to work, except the output is extremely low on the high level output. I found out that all the oscillators work as should, but once connected to the filters 10uF cap, the oscillator signal goes from normal few volts (peak-to-peak) to just a few millivolts (around -1v). If non of the on-off switches are connected to "AUDIOMIX" I have normal signal on scoop on both sides of the R201 (33k), but once I connect SW5 pins 2 and 1 scoop only shows slight movement around -1V. All the "AUDIOMIX" inputs work the same way.

I have done external wiring, but problem isn't with that, because I removed all the switches and it still works the same way. I have jumpers on loudness etc. A440 works, but is as quiet as the rest of the synth. I did notice that for osc1&2&3&noise I had used B50k pots instead of B25k, does this make a difference? Or should there be a sort on the filter section on the pcb?

Filter works, vcf cv summer (aftertouch, mod section, key tracking), trimmers for range/reso/vca1/vca2, envelopes work..

It's got to be somewhere ;-)

Thanks!