Search found 831 matches

by jorg
Fri Jan 22, 2021 4:14 pm
Forum: Music Tech DIY
Topic: A couple of DIY releated quesitons
Replies: 3
Views: 129

Re: A couple of DIY releated quesitons

I'm curious about the label printers you mention - been looking for one like that myself. Can you give a link or name?
by jorg
Fri Jan 22, 2021 3:41 pm
Forum: Music Tech DIY
Topic: How to get 128 MIDI values to map nicely to filter cutoff
Replies: 17
Views: 194

Re: How to get 128 MIDI values to map nicely to filter cutoff

Definitely you want your filter to be expo controlled; that's the bunching-up part of the problem if you don't do expo.

Also, you should put a simple lowpass filter inside your Arduino to smooth out the values before you output them.
by jorg
Mon Jan 18, 2021 4:51 pm
Forum: Music Tech DIY
Topic: Basic Noob Question Re: Potentiometers
Replies: 4
Views: 117

Re: Basic Noob Question Re: Potentiometers

One more detail: There are two main flavors of pot: Linear Taper, and "Audio" (or "Log") Taper. Usually, a linear taper pot, has a "B" in its description or part number, perhaps something like "B10K", and an audio taper pot's description or part number would have an "A" - something like "A10K". Doep...
by jorg
Mon Jan 11, 2021 4:03 pm
Forum: Music Tech DIY
Topic: AS3360 VCA oscillating
Replies: 11
Views: 203

Re: AS3360 VCA oscillating

Did you include compensation capacitors on the op amps? What op amps did you use?
by jorg
Mon Jan 11, 2021 2:40 pm
Forum: Modular Synth General Discussion
Topic: Why self oscillate a filter?
Replies: 25
Views: 2491

Re:

supposedly the sine is very pure - apparently some FM enthusiasts don't use VCOs - just sine waves from filters. Even the tiny glitch on a typical VCO's sine wave is enough to cause real sonic "damage" in an FM setup. I've had much better luck with self-oscillating filters for FM (when I want sine ...
by jorg
Mon Jan 11, 2021 2:22 pm
Forum: Music Tech DIY
Topic: AS3360 VCA oscillating
Replies: 11
Views: 203

Re: AS3360 VCA oscillating

Schematic, please.
by jorg
Mon Jan 11, 2021 11:42 am
Forum: Music Tech DIY
Topic: Bringing an old synth back to life
Replies: 8
Views: 440

Re: Bringing an old synth back to life

I had an old synth (Korg Poly-800 II) that went all nuts. I changed the battery, un-seated, cleaned, and re-seated all the connectors. That fixed it right up.
by jorg
Mon Jan 11, 2021 11:38 am
Forum: Music Tech DIY
Topic: Vias on pads at JLC assembly
Replies: 9
Views: 294

Re: Vias on pads at JLC assembly

At my employer, it would be unacceptable to place a via on a pad. JLC is correct.
by jorg
Mon Jan 11, 2021 11:28 am
Forum: Music Tech DIY
Topic: Harry Bissell's Fast Response Low Ripple Envelope Follower
Replies: 246
Views: 26797

Re: Harry Bissell's Fast Response Low Ripple Envelope Follower

roglok wrote:
Wed Jan 06, 2021 12:04 pm
jorg wrote:
Tue Jan 05, 2021 10:25 am
...full-wave rectifier...
That looks very nice! I should measure the attack response as that's one of the key points of the Bissell design but would have to get the scope out of storage for that...
Looking forward to your observations! :hyper:
by jorg
Tue Jan 05, 2021 11:05 am
Forum: Music Tech DIY
Topic: Self syncing VCOs
Replies: 22
Views: 605

Re: Self syncing VCOs

One more thing. Can you share how long the cable between your PSU box and main unit is? And what gauge wire you used between them. Which connector-s? EDIT: Deja-Vu on this PCB layout and expo. I participated in another MW thread not too long ago where I remember suggesting building a thermal insula...
by jorg
Tue Jan 05, 2021 10:25 am
Forum: Music Tech DIY
Topic: Harry Bissell's Fast Response Low Ripple Envelope Follower
Replies: 246
Views: 26797

Re: Harry Bissell's Fast Response Low Ripple Envelope Follower

I don't see how this beats a carefully crafted full-wave rectifier with two-stage rectified ripple filter.
Envlope 5c Circuit.PNG
Envelope 5c Waves.jpg
by jorg
Fri Nov 20, 2020 1:45 pm
Forum: Music Tech DIY
Topic: Can anyone share a V2164 / similar LTSpice model?
Replies: 28
Views: 565

Re: Can anyone share a V2164 / similar LTSpice model?

2164.zip
(2.86 KiB) Downloaded 18 times
This includes a 2164 model in PSPICE and Tina TI formats. I've used it to develop various circuits.
by jorg
Thu Nov 19, 2020 4:15 pm
Forum: Music Tech DIY
Topic: DC removal for VCOs with a simple CR passive circuit?
Replies: 3
Views: 577

Re: DC removal for VCOs with a simple CR passive circuit?

If we assume the next circuit has an input impedance of at least 10K, you could insert a 16uF electrolytic in series. That would give a cutoff of 1Hz (or better, with most downstream modules). Because you know there is a positive offset, a polarized electrolytic would be fine (+side faces the VCO ou...
by jorg
Thu Nov 19, 2020 3:28 pm
Forum: Music Tech DIY
Topic: DIY Real Spring Reverb Pedal?
Replies: 12
Views: 281

Re: DIY Real Spring Reverb Pedal?

Think any of the euro spring reverb driver modules, but in a pedal. Maybe it doesn't actually exist other than that $300 French version ... I use an old speaker amp (just a few watts) with a series resistor to drive the spring. The series resistor is ~5x the DC resistance of the input coil; it flat...
by jorg
Thu Nov 19, 2020 11:52 am
Forum: Modular Synth General Discussion
Topic: Any advantages to Hz/Volt
Replies: 20
Views: 2911

Re: Any advantages to Hz/Volt

Surprised no one mentioned the effect on modulations. Ideally, a VCO has both an expo input for pitch control, and a linear input (V/Hz, but scaled automatically to the expo value) for FM. Linear FM is very useful for a wide range of sounds. Skipping the expo input merely transfers cost to componen...
by jorg
Thu Nov 19, 2020 10:12 am
Forum: Modular Synth General Discussion
Topic: Have you a bedside synth?
Replies: 44
Views: 1457

Re: Have you a bedside synth?

My studio is my bedroom, so I have a 9U Doepfer, iPads, drums, guitars, a 1980s Korg Poly 800 II, and miscellaneous pedals, FX, etc within a few feet of my bed. When I want to fall asleep doing synthesis stuff, I grab an iPad. Favorite apps: Audulus, Auria, Xynthesizer.
by jorg
Thu Nov 19, 2020 10:08 am
Forum: Modular Synth General Discussion
Topic: Modular Control via Brainwaves featuring TONTO
Replies: 9
Views: 361

Re: Modular Control via Brainwaves featuring TONTO

Delighted to see that TONTO has a happy home and a productive continuing life! Thanks for this update!
by jorg
Thu Nov 19, 2020 9:36 am
Forum: Music Tech DIY
Topic: DIY Spring reverb Q (spring tension)
Replies: 7
Views: 331

Re: DIY Spring reverb Q (spring tension)

Any type of transducer can work. Typically, big springs require big movements. Older reverbs took advantage of the parts that were available; speaker drivers and guitar pickups. But as long as you can transfer the audio signal to movement, you can influence a spring.... Are you driving the spring i...
by jorg
Wed Nov 18, 2020 9:15 am
Forum: Music Tech DIY
Topic: DIY Spring reverb Q (spring tension)
Replies: 7
Views: 331

Re: DIY Spring reverb Q (spring tension)

How do you drive/pickup a spring with piezos? Normally a rotary magnetic driver and pickup are used.
by jorg
Wed Nov 18, 2020 9:10 am
Forum: Music Tech DIY
Topic: FPGA-based music countdown timer
Replies: 5
Views: 308

Re: FPGA-based music countdown timer

I have no idea what this is about.
by jorg
Mon Nov 16, 2020 1:31 pm
Forum: Music Tech DIY
Topic: Battery Eliminators and "3.3v" instead of "3v" for two AAA Batteries
Replies: 11
Views: 320

Re: Battery Eliminators and "3.3v" instead of "3v" for two AAA Batteries

KSS wrote:
Sat Nov 14, 2020 6:32 pm
...some "dope" with a positive attitude comes along and convinces everyone to stretch a little farther, push a little harder so the water can be passed. Or maybe another "dope" is the negative type says just stop people, it's a lost cause...
:hihi:

Nerd joke alert! :foul:
by jorg
Fri Nov 13, 2020 5:03 pm
Forum: Music Tech DIY
Topic: Battery Eliminators and "3.3v" instead of "3v" for two AAA Batteries
Replies: 11
Views: 320

Re: Battery Eliminators and "3.3v" instead of "3v" for two AAA Batteries

I'll fess up to not fully understanding resistance, i.e. the resistance "inherent in a device" is something I hear a lot. Is that component based, like each piece of component is an adjustable nozzle? I'll just be as dumb as I am in this question. Metaphorically, is resistance a device's pushback o...
by jorg
Fri Nov 13, 2020 2:46 pm
Forum: Music Tech DIY
Topic: Need input on a DIY Logic circuit for modular synths.
Replies: 13
Views: 451

Re: Need input on a DIY Logic circuit for modular synths.

That's still not a schematic; it shows physical chip footprints, and you have said those aren't even the real chips.
by jorg
Fri Nov 13, 2020 11:48 am
Forum: Music Tech DIY
Topic: VCO with precise tracking in the MHz, for wavetable
Replies: 39
Views: 936

Re: VCO with precise tracking in the MHz, for wavetable

Back in 1982, I implemented a wavetable 3-channel oscillator without aliasing. It was based on a hardware frequency divider and a DMA chip. There is a tradeoff of the master clock frequency vs frequency accuracy (ability to use large fine-grained divisors). But there's no aliasing. Just make sure to...
by jorg
Fri Nov 13, 2020 11:11 am
Forum: Music Tech DIY
Topic: VCO with precise tracking in the MHz, for wavetable
Replies: 39
Views: 936

Re: VCO with precise tracking in the MHz, for wavetable

For a purely analogue approach, you could split the problem into two parts: an exponential converter, and a linear oscillator. There are plenty of examples of good expo converters around. For the linear VCO I would start here: http://cds.linear.com/docs/en/application-note/an14f.pdf You could look ...

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