'The sound of the search for OU'

[Slider2732]

Am posting this here, because, well, the original and intended person whom I wished to run the idea past has apparently just quit the board !
I had just found 2 CRT circuit boards and was to have taken the flyback coils off them. You know the thread I mean and this smiley summarizes my own thoughts, when wishing to check on peoples circuit developments -  
When I went to post it, the board came up with one of those messages about another reply has been made in the meantime.
Nice timing huh.


It's a music related project idea.

Here's part of what was originally written:
I've wondered about sound shaping effects from something like these partnered coils. What would happen to a wave within analog waveform shaping, if passed through such a system ? then filter it, send it back through.
Maybe concept circuits that pop up here at the forum could be integrated into a synth project. Efficient Joule Thief types, MOSFET drivers, step-up oscillators. Even OU project oscillator frequencies, such as the 1.73kHz, to raise a knowing smile.
'The sound of the search for OU' hehe

I hope to develop the concept in a working homemade keyboard.

[TinselKoala]

A hot-air gun works great for removing flyback transformers and other parts from old CRT boards. Way easier and faster than trying to desolder them one pin at a time with a soldering iron.
Turn the board so that the component side is down, solder side up, and heat the flyback pads with the hot air blast on "hi".
Just be sure that it doesn't fall on your foot when it comes loose!

[Chet K]

Mark
Quote
Am posting this here, because, well, the original and intended person whom I wished to run the idea past has apparently just quit the board !
end Quote
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Seems a misunderstanding ,I love Jean's comments and input [as I know many do]
Also, I have to say "Music and Musicians"  seems to be a thread that runs thru a disproportionate amount of OUR population [Lottsa Musicians here ]

I will reach out for him in a few days.

Thanks
Chet  

[Slider2732]

@TK - it was the lack of hot air that got me looking through boxes lol. 20F and snow = no workbench sitting.
Thanks for the tip and, yes, those pins can be stupidly difficult to remove. Another method is a good pair of pliers and leave parts of the board dangling...when not making a public video of course  

@Chet - A secondary idea includes people here as a specialized group. Worldwide vintage music electronics fixin'
To set up a respected, value for money system where members here would repair vintage keyboards, drum units, FX pedals. Shipping would be to the closest globally to the client.
As you say, people such as Jean and Grumage have interest in such pieces and many here would, I hope, enjoy the cooperation too of working on such projects. Not to say either of those respected guys would want to do such a thing, but that indeed there seems to be an interest in music making here at the forum
The item would arrive, a forum post started (private if wished) and the collective brains would troubleshoot. The owner could even drop in, view progress.

[Slider2732]

The synth is something that may take a year or something to make, but, this thread will 'stay open' for inclusions etc.
Of course, it may not get anywhere, but at least some of the gear built over the years so far can be fun tested, to see if they have sonic goodness trapped within.
A very partially built 2 octave 4 oscillator synth will be the basis for this. Everything except the keys is likely to be a handbuilt situation. The keys themselves are simple, 1/3rd size or something plastic things from a kiddie keyboard that was found in the street (left out for the trash). Ideally they would be better. It also needs a few pots and the plastic tops. Hopefully, somewhere down the line i'll run across something at a yard sale or thrift shop.
Will upload a pic of where the partly built one is up to. I'll need to dig it out ! It'll be 1970's analog to look at, wooden side cheeks are already done, though not much else

What i'd like to do is to incorporate circuits that people think would suit.
Any ideas appreciated.


A direction is that of hybrid synthesis..hope I don't lose anyone at this point lol
The concept is something that seems to be gaining traction these days, analog and digital to produce the sounds.
The sound generating would be part analog and perhaps digital wavetable based. Out through analog processing (the OU type project circuits especially). The sounds themselves could be triggered over MIDI.
A tall order ?
Not really. Have been looking at this today:
https://github.com/dzlonline/the_synth
An Arduino or a couple, 3, 4 could handle digital wavetable lookups for basic starter waveforms and sampled sounds, to compliment analog derived waveforms.
They also could handle the MIDI connection to a PC based sequencer.
With about half a dozen here, the Arduino seems a good route to take on the partial digital side

Here is an excellent commercial version of the direction that i'd like this to go in, the Arturia Microbrute:
http://www.musiciansfriend.com/keyboards-midi/arturia-microbrute-analog-synthesizer
And cross it with one of these old ladies, the Moog Minimoog:
http://www.vintagesynth.com/moog/moog.php

[Slider2732]

Pics of the part-build that is to be repurposed.

First pic, all the parts, circuits, elements that probably caused the project to be shelved !
Second pic, envisaged synth overall design.

[TinselKoala]

Some day... maybe.... I hope to be reunited with my Nord Lead.

http://en.wikipedia.org/wiki/Nord_Lead

[ion]

Some day... maybe.... I hope to be reunited with my Nord Lead.

http://en.wikipedia.org/wiki/Nord_Lead

And I regret parting with my Prophet V.      My brother is a collector and still has a Mini-Moog and a bunch of other vintage keyboards.
I'll ask if he has a Nord Lead. 

[Slider2732]

@ION - Prophet 5 or VS ?
Oh, speaking of Sequential... i turned down a Pro One in 1990 for 80 UK pounds, because it wouldn't fit in the car with the other gear just bought at the shop + I couldn't see how it saved patches

@TK - I like those Nord's, always have for the way they put the knobs back on synths !
Was funny in the mid 1980's, when every pop group allegedly doing 'live' performances on Top Of The Pops had a Yamaha DX7 in the set. And then, somehow, all the bands put the same scratches in the same places on their DX7's. There is only 1 other alternative hehe


Please do post your kit lists from times of old or current line up.
I'd like to include features that worked and their placements, rather than blindly go throwing stuff in anywhere.
Tentative thinking puts the devices as viewable through a clear rear perspex piece at the rear, with a couple of internal LEDs lighting them.

[Slider2732]

Some thoughts for directions on control logic and oscillators.
Focus will be on the Arduino microcontroller in this post.
I like the Arduino Pro Mini. They're tiny (similar to a pinky finger in size), cheap and I have several of them, which helps.

Firstly, perhaps most importantly, should it have any control logic ?
In my view, yes, for MIDI, routing, digital waveforms and perhaps global FX.

Should it have digital waveforms ?
Tricky. I would much prefer sound creation to be purely analog...but do have experience of bad wandering and the need to warm up the circuits until they behave.
It would seem a good idea to have digital oscillators. Though, nothing wrong with additional oscillations coming in from such things as Lidmotors Penny !

Should it have a screen ?
Too much of a bling or useful ?
That one is a maybe. It could take away from a pure look, but, add a lot of quick to check settings, operating values etc.
I have a 2.2" 320x240 65K colour screen that could be used. Or a tiny 0.96" OLED - too small in my opinion for ease of use.
Have screens been useful to you, on your gear ?


Present Arduino based Open Source systems that could be used, in full or part. For their functionality and to not reinvent the wheel in several areas.
MeeBlip anode: http://meeblip.com/
Code: https://github.com/MeeBlip/meeblip-anode
Good monosynth already !

Mozzi: http://sensorium.github.io/Mozzi/
Nice clean sounds and very flexible library.

AVRsynth: https://www.youtube.com/watch?v=v_j8ymWVYu8
A monosynth with a good external controls line up, MIDI In

Octo-Synth: http://www.cs.nott.ac.uk/~jqm/?p=605
8 note polyphony, 16 oscillators !

Granular Synth: http://www.notesandvolts.com/2014/07/build-auduino-granular-synth-part-1.html
2 oscillator rumbler, simple, pot controlled (until keys replace the pitch pot)

'Nastysynth': http://www.msarnoff.org/1bitsynth/
Video: https://www.youtube.com/watch?v=fDE_n_OJ8Sc
The demo of this thing is breathtaking. Video quality is rubbish, but the sounds are perfect renditions of every coin-op arcade machine of the 80's lol


More options: http://playground.arduino.cc/Main/ArduinoSynth

[Slider2732]

I've tried Mozzi before now and found it to have great potential, but, needed a lot of understanding on how it did what it did.
This evening, Octo-Synth and Auduino V5 were tested out...simply on a breadboard in the bedroom, with a 3.3V Pro Mini.

Octo-Synth works great. It uses just a single wire per 'key' and is up to 8 notes polyphonic right off the bat.
But, it just plays a rather simple tone, with slight decay. Would need serious code reworking to open it out.
I used simple breadboard wires to play a scale and that worked. Capacitive touch also gave a decent velocity sense ability.

Auduino is looking to be a fave to implement in a basic prototype sound engine setup.
By heck it's good (as they probably say in Grimsby)
It's driven by half a dozen 4.7K pots.
One of those pots is pitch and that's where i'll do a resistor network instead, to gain 2 1/2 octaves.
Then it's a case of twiddling pots to make decent start sounds.
It may stand on its own or be 1 oscillator of a 3 osc keyboard.  
Onward with envelope shaping + LFO, pitch bend, MIDI, plus the OU type circuits.


Auduino demo -
Nice enclosure on this one and he shows the quite amazing analog sound from what ought to be a horrible clicky digital stepper.

 

[Slider2732]

From: http://www.notesandvolts.com/

MIDI input circuit.
Handy for sequencer use or for external modules and keyboards to talk at it.
MIDI Out will be similar.

[Slider2732]

Today was to be a spinny motor day, to get on with fitting more coils to the MMG motor.
But, I 'got a hair' about something and had to build it, the Auduino granular synth.
My prototype thing on the breadboard had only an earphone on it and no controls as such.

5V USB powered, 5x random pots of 10K and 20K (due to no 5K), Arduino Pro Mini, output is to a spare PC type powered speaker.

Here's a quick demo of the sort of sounds it makes at this point...to follow will be key triggering and keyboard conversion, plus sending the output through an ADSR envelope section.
But mostly, this as it stands may enable some tests, such as mixing a square wave from a Lidmotor Penny circuit. Wireless electricity experiments to follow that, such as coil proximity affecting the pitch, like a theramin.
Successful experiments, or at least quirky results may then go forward to be within the actual synth.