Search found 429 matches

by smrl
Mon Jan 13, 2020 5:24 am
Forum: Music Tech DIY
Topic: PCBs as Front Panels ?
Replies: 179
Views: 14721

Re: PCBs as Front Panels ?

I have yet to find out how to make oval holes and milled cutouts (for sliders and displays for example. If anyone has tips on that, please :) I don't know specifically about how to do this in Eagle. But in KiCAD I've had luck specifying slots as custom footprints, and using oval hole shapes to spec...
by smrl
Thu Sep 12, 2019 7:23 am
Forum: Eurorack Modules
Topic: Starthief's Eurorack adventure, 2016-???
Replies: 549
Views: 43267

Jason from Starling here :) Seems like you're understanding it all really well, happy to see that. A few points that might help: The "Z" input in Via land is the 1v/oct input, it's more precise (doesn't much matter in this case) but we can't digitize it as quickly. So it's a wavetable morph paramete...
by smrl
Fri Aug 30, 2019 10:30 pm
Forum: Music Tech DIY
Topic: Analog Switch Confusion
Replies: 11
Views: 654

VL sets your switching logic levels. You should supply it with the voltage used for your microcontroller supply - if the microcontroller outputs 5V signals, put 5V on VL.
by smrl
Tue Aug 27, 2019 10:33 pm
Forum: Music Tech DIY
Topic: STM development board
Replies: 7
Views: 606

You're more likely to have a problem with soldering/desoldering/resoldering a chip trying to accomplish this than just to flash the chip after installing it. Also flashing a chip can help troubleshoot potential problems, so if your crystal isn't oscillating or if your power supply(s) aren't function...
by smrl
Mon Aug 26, 2019 2:53 pm
Forum: Music Tech DIY
Topic: Trapezoid VCO
Replies: 74
Views: 5881

i thought it was just a capacitance matching thing, increasing the similarity between the two integrators, since any imbalance will create asymmetrical waveforms. But then I noticed they're connected to + and - supplies. Balancing charge injection spikes between the supplies rather than coupling to ...
by smrl
Sun Aug 25, 2019 12:23 am
Forum: Eurorack Modules
Topic: Anything else out there like the WMD Geiger Counter?
Replies: 17
Views: 763

Starling's Via SCANNER module is designed to do just this, and in 3 dimensions (3 CV inputs for the "remapping")

https://starling.space/via/scanner
by smrl
Sat Aug 17, 2019 6:57 am
Forum: Eurorack Modules
Topic: MI Tides 2018 - Just Intonation Chords List
Replies: 8
Views: 729

One more example. Look at this chord in particular: { { 1.0f, 1 }, { 2.0f, 1 }, { 3.0f, 1 }, { 5.0f, 1 } }, // CCGD 1.0f is unity, the output frequency is the same as the reference. 2.0f is an octave. Octaves are identical between just intonation and equal temperament. It's a doubling of frequency. ...
by smrl
Sat Aug 17, 2019 6:30 am
Forum: Eurorack Modules
Topic: MI Tides 2018 - Just Intonation Chords List
Replies: 8
Views: 729

right, exactly. It will track a pitch perfectly. That becomes its tuning center. The derived pitches (the chords) will be intoned differently than in equal temperament. In 12TET, you don't have to worry about where your tuning center is, all the pitches are always in the same spot. On an equal-tempe...
by smrl
Sat Aug 17, 2019 4:34 am
Forum: Eurorack Modules
Topic: MI Tides 2018 - Just Intonation Chords List
Replies: 8
Views: 729

Yes, just intonation can sound close to equal tempered depending on which ratios you choose but they're not exactly the same. The perfect fifth for example is less than 2 cents off. See here: https://en.wikipedia.org/wiki/Equal_temperament#Comparison_with_Just_Intonation And I got curious so i looke...
by smrl
Thu Aug 15, 2019 9:54 am
Forum: Eurorack Modules
Topic: Oscillators, LFOs and EGs with bounds modulation
Replies: 33
Views: 1716

I'm not positive, but it looks like the ADDAC 506 min/max values control the minimum and maximum rate for the rise/fall slopes rather than the voltages. The 501 looks to set the bounds of the random values in this same sense. The bounds are independent of frequency here.
by smrl
Thu Aug 15, 2019 9:41 am
Forum: Eurorack Modules
Topic: Oscillators, LFOs and EGs with bounds modulation
Replies: 33
Views: 1716

Interesting. That looks to be an implementation of the technique I mentioned above involving rectification, which is one of 3 distinct "bounds modulation" techniques we've been discussing. Depending on your definition of bounds modulation of course. Personally, I don't know that any of them are defi...
by smrl
Thu Aug 15, 2019 8:22 am
Forum: Eurorack Modules
Topic: Oscillators, LFOs and EGs with bounds modulation
Replies: 33
Views: 1716

Yeah, I saw your design recently and thought it's an awful lot like an analog META! I think we're thinking along the same lines in lots of ways :) Another note: using 2 VCAs and half-wave rectifiers is definitely not the same, though it's another interesting approach - you're attenuating the positiv...
by smrl
Thu Aug 15, 2019 7:49 am
Forum: Eurorack Modules
Topic: Oscillators, LFOs and EGs with bounds modulation
Replies: 33
Views: 1716

Yes you could make that equivalence, if you scaled a CV so that it spanned 2 inputs. It's just an ordinary linear crossfader -- but the 2 VCAs that make up the crossfader are independently controlled. So for different Via firmwares we can use it to do different tricks -- we go into more detail on th...
by smrl
Thu Aug 15, 2019 7:42 am
Forum: Eurorack Modules
Topic: MI Tides 2018 - Just Intonation Chords List
Replies: 8
Views: 729

The intervals won't be the same as their equal tempered counterparts -- except for octaves. They're derived from simple ratios, like 4/3 or 3/2 or 45/32, rather than dividing up the octave into equally-sized steps. This means that there is a greater spectral similarity in the intervals (the harmonic...
by smrl
Tue Aug 13, 2019 2:30 pm
Forum: Eurorack Modules
Topic: Oscillators, LFOs and EGs with bounds modulation
Replies: 33
Views: 1716

I'm happy to see META sparking some conversation. I helped design it. Yes, what you're getting by injecting audio into the A and B inputs is AM, though you can do it simultaneously with two signals. Also, by multing the same signal into A and B and using the attenuverter on B you will get 4-quadrant...
by smrl
Thu Nov 01, 2018 7:35 pm
Forum: Music Tech DIY
Topic: STM32F405 troubleshooting
Replies: 4
Views: 343

make sure your crystal is oscillating.
by smrl
Tue Oct 30, 2018 3:38 pm
Forum: Music Tech DIY
Topic: Can Silkscreen Go Directly Onto Copper PCB Layer?
Replies: 5
Views: 528

Yes. I've heard it doesn't stick as well, but I haven't noticed any durability issues yet. At least for white, you will notice the translucency. Here's a few photos of prototypes. One shows the difference in contrast with the copper layer "bleeding through" a bit, the other shows how there can be an...
by smrl
Sat Mar 31, 2018 4:32 am
Forum: Music Tech DIY
Topic: 4 operator FM percussion module
Replies: 8
Views: 846

looks to me like when your decay-to-pitch level is all the way down your pot is shunting the output of the op-amp to ground... So if there's very little/no resistance at the bottom of the pot it's likely going to take the decay -> VCA signal down with it. I'd suggest putting a low-valued resistor li...
by smrl
Thu Jan 04, 2018 3:35 am
Forum: Music Tech DIY
Topic: 2164 analysis, and comparison to OTA
Replies: 17
Views: 2054

Thanks for the writeup!

Would you consider doing a comparison of the SSI2164's when they're available?
by smrl
Mon Dec 11, 2017 4:44 pm
Forum: Music Tech DIY
Topic: Implement constant +5 volts in a passive module... Diode?
Replies: 4
Views: 279

No, all you need is a resistor between 5v and your jack normal. Just trying to explain why. And if you choose to add additional passive attenuators, It may not behave exactly as expected. Not trying to discourage, just offering help. To be honest, it’s not clear how you expect this to work or how th...
by smrl
Mon Dec 11, 2017 1:26 am
Forum: Music Tech DIY
Topic: Implement constant +5 volts in a passive module... Diode?
Replies: 4
Views: 279

I'd suggest putting a resistor in series with the +5v. This will create a voltage divider with your LDR, so the max output will be something less than 5v, depending on how small of a resistor you use. Maybe 1k would work fine. Doesn't seem like you're concerned with precision with this circuit :hihi...
by smrl
Fri Jun 23, 2017 12:53 pm
Forum: Video Synthesis
Topic: LZX Cadet VCO layout DIY
Replies: 14
Views: 2928

yeah, I did mean pin 3. Sorry about that :)
by smrl
Fri Jun 23, 2017 11:01 am
Forum: Video Synthesis
Topic: LZX Cadet VCO layout DIY
Replies: 14
Views: 2928

Yeah, that net is connected to R8, R25, C18, and pin 2 of 74HC14 (U12). Nothing else.
by smrl
Sun May 21, 2017 10:12 pm
Forum: Video Synthesis
Topic: 3d image manipulator << SOLVED! >>
Replies: 22
Views: 3319

Yes, internally it is all OEI modules on daughterboards. It's just branded Data Check. I don't know if there were other manufacturers or not. https://www.muffwiggler.com/forum/download.php?id=11757 There is the documentation, also at one time I had the OEI 6125A datasheet (which is the rotator IC) a...
by smrl
Sun May 21, 2017 10:06 pm
Forum: Video Synthesis
Topic: 8 channel vactrol-based video sequencer
Replies: 79
Views: 12670

I still have a few built modules left, if any one is interested. $160.

j

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