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Davesax1965 View Drop Down
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Direct Link To This Post Posted: October 31 2015 at 06:01
Thanks, Dean ! Ahhh, ETI synths, I remember ETI coming out with the first designs. I remember knowing about four people who started building them - none got finished.

If you have a look at Eurorack systems now, anyone can build (or buy, off the shelf) a modular. I decided to build my own as I had electronics as a hobby. You don't have to know much. I am no expert, I can tell you how an oscillator works but not, for example, how to put the waveshapers together. I'm just doing this to save money and for the pleasure of building it myself.

I can well believe that about the VCS3 !!!! You can still get them, y'know, EMS produce them for 1800 each. I was amazed to find out that Peter Zinovieff is still going.....

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Direct Link To This Post Posted: October 31 2015 at 06:02
Interesting thread seeing all those photos and reading that technical information about early synthesizers. I guess it's not as much the books I've read that were wrong as a combination of my memory being rusty + my limited knowledge of hard technological stuff like that!
"The past is not some static being, it is not a previous present, nor a present that has passed away; the past has its own dynamic being which is constantly renewed and renewing." - Claire Colebrook
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Direct Link To This Post Posted: October 31 2015 at 06:04
Definitely the books, Toaster. There is so much of a mythology about Hawkwind...... ;-)


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Direct Link To This Post Posted: October 31 2015 at 06:06
What, exactly, is a 'tone generator' - as opposed to a 'regular' synth ??
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Direct Link To This Post Posted: October 31 2015 at 06:17
Just creates a sine wave. 
The sine wave can be sent down, for example, a length of telephone cable. Attach test equipment at the other end, eg. an oscilloscope. Do you see a sine wave at the other end or has it been altered - is there noise on the line ? Could be electromagnetic interference, etc. 

Also used to produce a tone which is even and can be used to test, say, recording studios or environments. Test generators generally died out in the late 60's. You may find a few lying around today.

An oscillator..... a VCO or "voltage controlled oscillator" -  is slightly more complicated. Here's one I built earlier - sounded very Blue Peter, then. ;-) This is a multi waveform oscillator. It can produce sine waves, but sine waves are very boring. So you can also select (via the jack sockets below) sawtooth, square, triangle - etc - waves. There's an octave knob above (the large white one) - set it to 32, very low note, 16, note an octave up.... etc. 9 octave range. And very accurate too, generally to about 2 cents. The numbers refer to lengths of organ pipe, believe it or not. 

So a test generator is a simple sound producer. An oscillator is usually better built, more accurate, multi waveform and designed to interface with filters, amplifiers et al. 

This works on having an input of +5 to -5 volts. Go up one volt, the pitch changes by one octave. "Control voltage" is what analogue synths work on, but all have different standards. Which is a bit of a headache and why I'll have the soldering iron out this afternoon, converting the output from a sequencer to one which my Korg synth expects to have as an input. 




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Direct Link To This Post Posted: October 31 2015 at 06:20
Any of you folks interested in Eurorack / modular synths / synth DIY, do pop over to the very pleasant Muffwiggler forum - tons of us on there and you'll be made very welcome ! ;-)

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Direct Link To This Post Posted: October 31 2015 at 06:23
Originally posted by Davesax1965 Davesax1965 wrote:

Thanks, Dean ! Ahhh, ETI synths, I remember ETI coming out with the first designs. I remember knowing about four people who started building them - none got finished.
Me too - I even bought the book (which I still have somewhere):
maplin_catalog.jpg - 29.5 K
...to a 17 year old fan of electronics and electronic music that was geek-porn back in 1974 (and I don't mean the two ladies bizarrely dressed in regency costume).

Originally posted by Davesax1965 Davesax1965 wrote:

If you have a look at Eurorack systems now, anyone can build (or buy, off the shelf) a modular. I decided to build my own as I had electronics as a hobby. You don't have to know much. I am no expert, I can tell you how an oscillator works but not, for example, how to put the waveshapers together. I'm just doing this to save money and for the pleasure of building it myself.
I had a quick look at the Doepfer Dark Times sequencer manual, while I couldn't find a circuit diagram I see from the board layout they use a PIC18 microcontroller, which is pretty much how I'd do it now-a-days. In fact I'd wouldn't be surprised if a lot of the modules were based around cheap microcontrollers as they provide a good stable way of "reprogramming" analogue circuitry.

Originally posted by Davesax1965 Davesax1965 wrote:

I can well believe that about the VCS3 !!!! You can still get them, y'know, EMS produce them for 1800 each. I was amazed to find out that Peter Zinovieff is still going.....
...it's one of those things that if I had the spare cash and if I had the space I'd buy one just because...
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Direct Link To This Post Posted: October 31 2015 at 06:35
Fantastic !!! ;-) 

Yep, the Dark Time has a digital heart nowadays. It's only running clocks - the output is good old analogue. ;-)

Mine has Fancy Wooden Sides, as does the Korg MS20 Mini. (Used to have an original MS10 30 years ago).

You can bolt two Dark Times, or a Dark Time plus Dark Energy, or any combination thereof, together. Which I shall be doing. ;-)
Very boring video here - DT to Korg - wooden sides in post ! 
https://www.dropbox.com/sc/3twdmjwh7qq7dtv/AAC1S2UqRbQvHcubTpObLU3oa





Edited by Davesax1965 - October 31 2015 at 06:41

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Direct Link To This Post Posted: October 31 2015 at 06:39
The VCS3 stuff on Floyd's DSOTM is superb (On The Run, Any Colour You Like)......
Gilmour used one on The Endless River, surprisingly enough.
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Direct Link To This Post Posted: October 31 2015 at 06:42
Originally posted by Davesax1965 Davesax1965 wrote:

Just creates a sine wave. 
The sine wave can be sent down, for example, a length of telephone cable. Attach test equipment at the other end, eg. an oscilloscope. Do you see a sine wave at the other end or has it been altered - is there noise on the line ? Could be electromagnetic interference, etc. 

Also used to produce a tone which is even and can be used to test, say, recording studios or environments. Test generators generally died out in the late 60's. You may find a few lying around today.
{note: I'm a test engineer by profession Wink} We still use simple sinewave generators though not the valve oscillators of old. Interestingly, those worked on the hetrodyne principle (same technique Bob Moog used in his theremin) to produce audio tones from two RF oscillators as it was a lot easier to make stable RF frequencies, which is why they would "swoop" when you adjusted the frequency control. The test generators we use today are far more sophisticated and have price tickets in the $10K range, and because the are so stable and precise it makes them less interesting from sound generation perspective. The equipment I use to test embedded ADCs and DACs employs ($100K+) arbitrary waveform generators that I can preload with whatever waveform shape I care to create.


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Direct Link To This Post Posted: October 31 2015 at 06:44
A lot of bands still do, Tom. Jimi Hendrix, Moon turn the Tides. There's still a great affection for it.

This is the latest pic of the modular. I'm building some case lighting using electroluminescent wire (look it up) - this is "voltage on." I had one module (which I didn't build) burn out as it'd been shipped to me with the cable on the wrong way around. Reversing polarity is not recommended at all in systems with 1/8W resistors in....
The case has two expanders top and bottom, the logo has gone, room for more modules, in this case, patch connectors. Another two row case will sit on the top of this.

And a link to the least exciting video on the internet - 
https://www.dropbox.com/s/qxv8u5bhzwwo8ga/2015-10-25%2014.25.04.mp4?dl=0






Edited by Davesax1965 - October 31 2015 at 06:50

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Direct Link To This Post Posted: October 31 2015 at 06:45
Lots of hand made bits - hand made control panel which triggers four external clocks which can be used to modulate filters, etc. It also contains an A440 reference tone unit, ring modulator and the case lighting controls. All to be wired up. ;-)






Edited by Davesax1965 - October 31 2015 at 06:47

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Direct Link To This Post Posted: October 31 2015 at 06:49
Originally posted by Davesax1965 Davesax1965 wrote:

Fantastic !!! ;-) 

Yep, the Dark Time has a digital heart nowadays. It's only running clocks - the output is good old analogue. ;-)

Mine has Fancy Wooden Sides, as does the Korg MS20 Mini. (Used to have an original MS10 30 years ago).

You can bolt two Dark Times, or a Dark Time plus Dark Energy, or any combination thereof, together. Which I shall be doing. ;-)
Very boring video here - DT to Korg - wooden sides in post ! 
https://www.dropbox.com/sc/3twdmjwh7qq7dtv/AAC1S2UqRbQvHcubTpObLU3oa



There is lovely elegance in the shaping of those wooden cheeks. One of my bug-bears about home-builds is they often look too home-made, when I was an apprentice the phrase "it looks like you made it" was used as a put-down to anyone who hadn't put any thought or care into the finished product. This criticism cannot be levelled at you - everything looks very nicely done sir. Approve
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Direct Link To This Post Posted: October 31 2015 at 06:51
Lovely, aren't they ?

Just waiting for the Korg sides to come from the US .....



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Direct Link To This Post Posted: October 31 2015 at 06:53
And
Synth 1 of 2. This is my brother's synth, he bought most of it off the shelf although there IS some hand made stuff in there. 
This is "finished", although he is threatening to add another cabinet. ;-)




Edited by Davesax1965 - October 31 2015 at 06:57

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Direct Link To This Post Posted: October 31 2015 at 06:56
- when we do a gig, it'll be in pitch blackness BUT

I've just discovered electroluminescent wire. Got a kit of 18m of flourescent neon wire plus inverters coming next week. 

Expect a lot of.... this. Eventually. ;-))))
And yes, it can be made to move...... 



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Direct Link To This Post Posted: October 31 2015 at 08:54
Great pix, Dave! Love the hard specs.
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Direct Link To This Post Posted: October 31 2015 at 09:16
Thanks, Versilibre !

Daytime - yep - shots of EL Wire, which we may be using on stage. Neon glow wire, good for case illumination. And it looks, er, fairly good !!!!



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Direct Link To This Post Posted: October 31 2015 at 09:26
Released date are often when it it impacted you but recorded dates are when it really happened...

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Direct Link To This Post Posted: October 31 2015 at 10:21
Originally posted by Davesax1965 Davesax1965 wrote:

- when we do a gig, it'll be in pitch blackness BUT I've just discovered electroluminescent wire. Got a kit of 18m of flourescent neon wire plus inverters coming next week

I'm not a convert myself lots of 100v ac inverters and wires (aerials) radiating em-waves at audio frequencies can be a bugger to screen sensitive equipment from.
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