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FINALLY! I believe I have gotten to the bottom of the invalid session and logout issues. Please continue to report your own experience in the appropriate threads in the "Forum Discussion and Requests" subforum. Thank you all for your patience and support! <3

Presenting: Crowminius
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page Previous  1, 2, 3 ... , 36, 37, 38  Next [all]
Author Presenting: Crowminius
p4rancesc0
thanks, more ore less it will cost the same with shipping to italy
clofstedt
anybody know how I can get a hold of a pre programmed midi Atmega chip? I am lost
oldcrow
I am going to stock more this weekend. --Crow

clofstedt wrote:
anybody know how I can get a hold of a pre programmed midi Atmega chip? I am lost
beedogs
Has the value of C119 changed in the 1.1.3 revision? Looks like it's a .47 uF film cap -- that's an awfully large (dimensionally) cap, it seems to crowd out the IC and the transistors around it.
lowell513mx
Is anyone familiar with the Social Entropy Engine sequencer? Will the Gate & CV on the Engine work with the Crowminius?

"Precise 16-bit outputs with a true bipolar output swing from -3V to +7V make it possible to get the most out of your analog synthesizers.

Gates output a +10V signal, which is perfect for triggering some older machines."
aquatarkus
Check this out - I think this may answer your question...

oldcrow wrote:
+14V gate would not harm anything, but it might make the EG action a bit strange as the input voltage would be greater that the supply rail. The easiest solution would be a 5.1v zener across C95 (anode to ground). This would clamp any voltages past 5.1v. --Crow

aquatarkus wrote:
Hey Crow -

I'm building the ARP 1601 sequencer clone when the 3rd run is available a little bit later. I was hoping to use it with the Crowminius, but after reading online it looks like the gate voltages are different.

The creator of the 1601 project said,

"I think you'd need to find out from the relevant developer/supplier of your intended modules whether a +14V gate is OK or too high, in which case a simple resistor/zener diode network, which you could even build into a plastic 3.5mm jack plug on a special patch cable, would do the trick. Failing that it would be quite easy to make up a simple voltage reducer for all these signals on a bit of strip board."

So - would the +14V gate be too high for the Crowminius and will I need to come up with a way to step that down to use with this synth?

Thanks!
lowell513mx
thumbs up

aquatarkus wrote:
Check this out - I think this may answer your question...

oldcrow wrote:
+14V gate would not harm anything, but it might make the EG action a bit strange as the input voltage would be greater that the supply rail. The easiest solution would be a 5.1v zener across C95 (anode to ground). This would clamp any voltages past 5.1v. --Crow

fomtoberheim
Hey if i wanted to build this with an internal power transformer and an iec cable. Would i be able to find a transformer that supplies power to both inputs on the "Power supply that does not suck". J19 J18 J17?
Le_paulf
Looking b25k, a50k potentiometers with a D shaft.

Anybody know where I can find them?

jimfowler
fomtoberheim wrote:
Hey if i wanted to build this with an internal power transformer and an iec cable. Would i be able to find a transformer that supplies power to both inputs on the "Power supply that does not suck". J19 J18 J17?


As per Scott when I asked him basically the same question it's totally fine to do so. Just make sure you get a correctly sized/spec'd tranny.
jimfowler
I don't plan on incorporating the pitch wheel...should I jump the potentiometer solder points, find a resistor that's the median value of the pot that would normally go there or just omit the pot entirely?

Thanks.
beedogs
Having MAJOR problems with the note scaling on a 1.1.3 rev board. It seems to be affecting every oscillator, no matter what I set the zero/scale/octave trimmers to. The voltages look correct up to and including pin 1 on IC1, but here's what a C major "scale" (from C to B) sounds like:

http://bitey.net/crow2.m4a

This is with both OSC1 and OSC2 sounding at the same time. You can hear the pitches are roughly the same, but they're just way too far apart from one note to the next. (This can be replicated using both MIDI and CV control.)

I've double-checked all the resistor values in the pitch circuitry and everything seems spot on. Really not sure where the problem could be. Any ideas? hmmm.....
beedogs
Welp... I give up.

Nothing seems to be even close to in tune, no matter what I substitute for R4, and I'm getting a whole lot of crosstalk somewhere in the output stage. Any time the PWM LEDs light, there's a burst of low-frequency noise on all outputs.

Has anyone actually successfully built a rev 1.1.3 board? seriously, i just don't get it
peAk
beedogs wrote:
Welp... I give up.

Nothing seems to be even close to in tune, no matter what I substitute for R4, and I'm getting a whole lot of crosstalk somewhere in the output stage. Any time the PWM LEDs light, there's a burst of low-frequency noise on all outputs.

Has anyone actually successfully built a rev 1.1.3 board? seriously, i just don't get it


Don't give up. I had very similar problems to you but finally worked it out by socketing a resistor (not looking at the schematic right now) on two of the oscillators in the scaling section of the circuitry and was able to finally get to scale by tweaking that resistor value. I always assumed it was a tolerance stack up somewhere, cause like you, I had triple checked everything and I had correct values. If you search back through these pages, you should be able to find my posts. I can also dive deeper if there is not enough info on the thread.

Unfortunately, like you, I get that noise when the pulse width LEDS light up too. I was able to minimize that noise by disconnecting the leds but it will still come back after some time. Something to do with heat because the noise is never there for me when it's just turned on. It's seems to start 30 minutes or so after its been on.

If you, or Crow, ever figure out what causes that noise, I'd love to fix that.
jimfowler
So, finally got everything wired up and I have no sound. I haven't programmed the atmega chip yet, so I can't test the 440 tone and thereby check the vca.

My +/-10V are spot-on...however, where I'm supposed to have -5V I have upwards of -10V (except for pin 3 of IC2 - there I have exactly -5V). Specifically, at A6/C6 of the octave selectors I'm not getting the right amount of juice. At pin 7 of IC2 my voltages jump from 0 to -5.XX and on up to about -7.85 as I'm clicking through the range. I have -9.7V at all legs of Q1.

I'm good enough to bumble my way through tube gear but this shit is over my head. Any pointers would be most appreciated.

- Jim

EDIT - fried Q1...replaced it and we're now making progress.
oldcrow
Is this pitch CV from external input or from onboard DAC? Each one needs a different resistor value for R4. (100K for DAC, 121K for ext CV)

beedogs wrote:
Having MAJOR problems with the note scaling on a 1.1.3 rev board. It seems to be affecting every oscillator, no matter what I set the zero/scale/octave trimmers to. The voltages look correct up to and including pin 1 on IC1, but here's what a C major "scale" (from C to B) sounds like:

http://bitey.net/crow2.m4a

This is with both OSC1 and OSC2 sounding at the same time. You can hear the pitches are roughly the same, but they're just way too far apart from one note to the next. (This can be replicated using both MIDI and CV control.)

I've double-checked all the resistor values in the pitch circuitry and everything seems spot on. Really not sure where the problem could be. Any ideas? hmmm.....
beedogs
peAk wrote:


Unfortunately, like you, I get that noise when the pulse width LEDS light up too. I was able to minimize that noise by disconnecting the leds but it will still come back after some time. Something to do with heat because the noise is never there for me when it's just turned on. It's seems to start 30 minutes or so after its been on.


That's what seems to be happening with mine, as well. When I haven't had it on for a while it seems normal, but once I've had it on for a while the noise starts, after about 15-20 minutes.
beedogs
oldcrow wrote:
Is this pitch CV from external input or from onboard DAC? Each one needs a different resistor value for R4. (100K for DAC, 121K for ext CV)


I've got it socketed now and have tried various values for R4 from 160k down to 100k, using both CV input and MIDI input from the onboard DAC. They all seem to give the same very very wide range of pitches.

What's strange is when I measure across pins 5 and 7 on IC1, the (MIDI) pitch suddenly becomes perfectly accurate with a 101k resistor in R4. When I take the probe off those pins, it's back to being extremely out of range.
blandoon
Anyone using the bottom-mount Alpha switches (from Jameco) for the waveform and octave selectors: what are you using for knobs? Those are 6mm D-shaft, and I'm having a hard time finding anything that looks right and has the right fit.
pokeyasd
Hello oldcrow,

I would like to ask if at this point you're able to disclose the future of this project? I'm highly interested in building this and I'm thinking of purchasing a bare PCB, as they are in-stock now, but I probably won't have the time or resources to build it for a long time yet (months probably, years maybe). Therefore I'd like to know will this be available as DIY project still for some time and will there be improved versions? I'm under the impression that at some point there will be ready-made product for sale, but I don't know if it will replace the DIY product.
peAk
beedogs wrote:
peAk wrote:


Unfortunately, like you, I get that noise when the pulse width LEDS light up too. I was able to minimize that noise by disconnecting the leds but it will still come back after some time. Something to do with heat because the noise is never there for me when it's just turned on. It's seems to start 30 minutes or so after its been on.


That's what seems to be happening with mine, as well. When I haven't had it on for a while it seems normal, but once I've had it on for a while the noise starts, after about 15-20 minutes.


any luck with the noise issue?
sk23
Hello,
I've a working Crowminius v1.1.
I would like to control via midi:
1) pitch bend
2) mod wheel
3) filter cutoff

With the actual firmware those control don't work via midi (I use the standard 4 pin DIN connector, no CV).

Someone can explain me please if it's possible to implement, and how, those functions.

Thank you

Regards
oldcrow
Make sure you are using a 12VAC wall-pak (or internal case transformer if that is the way you are going) that can supply 500mA. Lower current ratings will cause things to go all funny. --Crow

peAk wrote:
beedogs wrote:
peAk wrote:


Unfortunately, like you, I get that noise when the pulse width LEDS light up too. I was able to minimize that noise by disconnecting the leds but it will still come back after some time. Something to do with heat because the noise is never there for me when it's just turned on. It's seems to start 30 minutes or so after its been on.


That's what seems to be happening with mine, as well. When I haven't had it on for a while it seems normal, but once I've had it on for a while the noise starts, after about 15-20 minutes.


any luck with the noise issue?
ElSmurf
jimfowler wrote:
I don't plan on incorporating the pitch wheel...should I jump the potentiometer solder points, find a resistor that's the median value of the pot that would normally go there or just omit the pot entirely?

Thanks.


Did you get this sorted out? I'm not using a pitch wheel on mine either.
oldcrow
To disable the pitch wheel, you want to "lock" a DC voltage into the pitch wheel node of the CV input summing amp. The easiest way is to just use a couple of 10K resistors where the pot would go, one from CW to center, and one from CCW to center. This places 5V on the pitchwheel node, which is needed to get other things into the correct default range. -Crow

ElSmurf wrote:
jimfowler wrote:
I don't plan on incorporating the pitch wheel...should I jump the potentiometer solder points, find a resistor that's the median value of the pot that would normally go there or just omit the pot entirely?

Thanks.


Did you get this sorted out? I'm not using a pitch wheel on mine either.
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