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Showing posts from 2018

Mad Bees! Avalanche Ramp Oscillator--Smells like Insect Spirit

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Greets again fellow synth nerds:

I broke my own rule of DIY and perfboarded a new design. The rule: I figure it's quicker these days for me to use Eagle to craft a PCB I want to mess with, kludge in any parts, and see if I can get it to work.  If I can great, if not, toss it and start over....but not this time....

The back story:

I was up late watching my usual youtube electronics vids to help me fall asleep (Carlson's lab is a favorite for that! 2+ hours of a Canadian tech saying "abooot" while restoring a tube amp? This guy is awesome!) and came across this Colin Furze clone DIY audio dude. At least he's a synth player, he doesn't ride around on jet powered bicycles and you gotta love that earring!

Close enough!

OK Sir Thomas Dolby-Colin Furze's kid brother has a super fun series of vids about using a NPN as an "avalanche oscillator".  (BTW I really like his videos! All kinds of great stuff! Mr. Carlson's energy and then some! Ah...to be …

Arduino based SYNTHDVM--Up and Running.

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Hello again, yes it all works.

The SynthDVM is as far along as I think i will take it.

For anyone who wants to catch up:

Part 1  is here--as I try to master the art of undocumented Arduino clones and parts

Part 2 is here. Design goals for the project.

Part 3 is here. Let's get the OLED meter to look "analog"

Part 4 is here.  clobber that op amp!

About the DVM, It reads DC from about -10.5 to +10.5V with an accuracy of better than 1% throughout its entire sweep--very close to .5% for say 5V and pretty much dead on between +/- 3V.  As they say (I say)  in audio DIYland "good enough".

If I designed a custom PCB for this, which I see little point in doing, with a good layout and large ground plane, it'd probably perform better but it's not bad for a sandbox PCB, a nano, and a handful of opamps.

There were some evenings of cursing over this one, I had some ripple on the Opamp + and - rails I couldn't get rid of, but I finally re soldered a few traces here an…

Synth DVM part IV: Neat Arduino Trick--good for Audio DIY--Crush that op amp!

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I finished (!!) my arduino based Synth DVM, it worked last night anyway; need to do a few final software tweaks then will post.  As always I am sure someone can improve it, but it's working well.

You can see part 1 here--I try to master the art of undocumented Arduino clones and parts

Part 2 is here.  Design goals for the project, Blah blah ginger blah blah.

Part 3 is here.  Let's get the OLED meter to look "analog"

How it looked about a week ago...front panel an "alubase PCB" from PCBWay....the PCB is already bolted on. Along the way I found a cool and easy way to make an Arduino treat audio like it's running through 4066 cmos switcher. Maybe better?

It's a nifty enough trick that I thought it should have its own post.





The hack goes like this:
If you've screwed around with Arduino for more than a few minutes you find the things don't like negative voltages w high current on their analog pinssince my SynthDVM is chock a block with negativ…

40106 Quad opto coupled VCO--Lunetta Lives!

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All hail Lunetta Synthesis--the CMOS anything-goes way of thinking about Audio DIY?



One thing that appeals: Stanley Lunetta is from the California Central Valley, same as me--from my reading his studio was about 40 miles from where I was recording back in the day.

Does this prove that we Central CA folks aren't all farmers and politicians?  Does it need to be proven? Growing up I remember a great music scene, at least in the 70s. Makes sense--there was very little else (legal) to do!

OK: In honor of Lunetta Synthesis and all Central Valley artists I decided to fab a quad VCO one of the great CMOS chips, the 40106.

I've messed with this chip before but this was my first attempt at doing something this, well, VCOish.

I went through a few generations of experimenter boards by designing in Eagle, and sending off to EASYEDA for a test fab.  I almost have given up on perf'ing things. It's faster and easier for me to have boards fab'd abroad, sent back to the US, and if …

DIY Synth and Electronics Pseudo Silkscreening using "Lazertran"--How To Do This!

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I am still trying to figure out how to make low-cost, low quantity front panel silk screen art but can't solve that one out.

And: I have tried etching/fabrication services like Front Panel Express but find their CAD tools difficult to use and their services expensive for one-offs.

The good news: I have been using a water slide decal process to get me close to silk screen type front panel finishes using something called "Lazertran".

That's what this post is about. No, I don't work for these guys. This isn't an ad but it is the best way to do this I have found to date however.

So if you already have your metal work done and want to get close to professional looking, one-off front panel art,  for about $1-$2 USD per panel, please read on.

Still with me?

First, go out and get this stuff: "Lazertran."  You can find it online direct, also at Blick Art, Amazon, and several other online suppliers.  Your local art store may also have it, or maybe can order it…

QUICK ONE: Super Microvcf--8 components?

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Quick one--

I am on a quest not sure why to find a VCF with the lowest parts count.  I could get one of those one Curtis chip clone solutions but that's cheating?

I created a long time ago a Vactrol VCF that's pretty low but I may have beaten it here....

I found this on the web.  8 parts!! It's from an old PAIA stompbox design.

I can sort of understand how it works I think, we are robbing current from the Op amp's feedback path, which changes the cutoff frequency.....but I was curious how it sounded, so I perf'd it.

I tried different cap values--anything from .01 to about .2 is worth a listen. The NPN can be whatever I figure, I used a 3904.  I used a 741 for the opamp since that seems appropriate for the era.

The 1MB values must be to not suck too much current out of whatever is feeding this filter I am guessing.  I didn't mess with those values, but overall, parts values are not critical; from messing with this micro circuit the caps can be different values f…

Creating Custom GUI Elements in Reaktor 6

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Putting down the soldering iron this week to focus on software that lets you DIY your own FX plug ins--Native Instruments Reaktor.

With Reaktor 6 you can whip up synths and what not, I feel Reaktor synths usually sound a bit thin, but for recording projects, Reaktor is VST duct tape, used to solve simple and maybe not simple problems.

Need to flip L and R channels in a WAV file?  Reaktor can do that (it's easy).  Need to make a stereo WAV into a mono file and control overall volume of the result?  Easy.  Need to rerecord a stereo file as mono, add EQ and a tape delay, then use the whole Mishpucha as a VST in Ableton, and then loop it?  You can do this with different software, but Reaktor makes it really easy.  Those are some damn clever guys at NI. Audio duct tape!  Yeh!!!!

For instance: I did a session the other day where the DJ dude wanted a drum roll that started at normal speed and slowed down in a controlled manner. There are probably 100 ways to do this, but to see if I coul…