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Old 29th May 2019, 4:11 pm   #1
dave_n_t
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Default ETI Wave (sound) simulator

Whilst tidying my old projects, I found a wave sound (i.e., the sound of the sea) simulator which I made some years ago. It was made by (amplitude) modulating white (or maybe pink) noise in various ways.


I gave away all my old ETI magazines, which is where it came from (I actually labelled the piece of veroboard) - so now I can't work out the connexions. I can easily trace loudspeaker, and power, but there were another few external controls for which I only have veropins!


I'd be very grateful if anyone could identify the article (and hopefully I can then download it from the excellent American Radio History site).


dave
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Old 29th May 2019, 5:45 pm   #2
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Default Re: ETI Wave (sound) simulator

Hi Dave.

Circuit diagram I still have about 25 Pcbs for this project. They work very well. pm me for more info.

Bob.
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File Type: pdf ENVIROSYNTH A3.pdf (550.8 KB, 168 views)
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Old 29th May 2019, 6:05 pm   #3
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Default Re: ETI Wave (sound) simulator

Bob,

Many thanks - but that's way more complex then the one I made. It has a quad op-amp (TL084 etc) for the modulation, and a small class-B discrete amplifier for output; and a couple of discrete transistors for the noise source.

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Old 29th May 2019, 8:44 pm   #4
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Default Re: ETI Wave (sound) simulator

Dave, try 1997 issue 1 (January) Page 33 onwards:

https://www.americanradiohistory.com...97-26-No-1.pdf

You didn't mention biofeedback in your OP but it has the two transistors as noise source, quad op-amp plus small amplifier IC structure that you mentioned.
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Old 29th May 2019, 9:23 pm   #5
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Default Re: ETI Wave (sound) simulator

Oh, wait, sorry you said a small class B -discrete- amplifier. That can't be the one, then. Try looking through this (almost complete) ETI index to see if you can narrow it down.

http://santaroga.xyz/2019/03/13/the-...ete-eti-index/
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Old 29th May 2019, 11:16 pm   #6
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Default Re: ETI Wave (sound) simulator

Many thanks for this link - I'd tried looking at individual ETI indices (which is somewhat tedious!).

But I still can't find it - names that might be the right thing led me to look at dec 95, dec 96, 97 #1, nov 87, dec 87, apr 82, may 82, apr 76, and jun 96.

I suppose it's possible it was in a TechTips: I may try that route tomorrow.
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Old 30th May 2019, 6:46 am   #7
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Default Re: ETI Wave (sound) simulator

Although the schematic Bob posted may be more complex it is worth considering, I have heard it and it really does sound like waves gently lapping on a beach.
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Old 30th May 2019, 7:25 am   #8
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Default Re: ETI Wave (sound) simulator

The schematic Bob posted looks very good. It uses a PRBS randomiser to control the modulation so the waves don't come in with boringly metronomic regularity. Even the spare opamp section is properly parked!

If there are boards available, this one looks worth building.

David
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Old 30th May 2019, 11:30 am   #9
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Default Re: ETI Wave (sound) simulator

Thanks, all.

I have one wave sound simulator, and that should be enough (albeit I can't actually figure out the connexions yet)!
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Old 31st May 2019, 9:02 pm   #10
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Default Re: ETI Wave (sound) simulator

Quote:
Originally Posted by Bobdger View Post
Circuit diagram I still have about 25 Pcbs for this project. They work very well. pm me for more info.
Hi Bob.

Looks an excellent project to build. PM sent re PCB. Thanks.

Regards,
Symon
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Old 4th Jun 2019, 10:18 am   #11
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Default Re: ETI Wave (sound) simulator

Well, I finally got to the bottom of this.
My labelling of the original circuit was clearly wrong.

The circuit was from Elektor. I found a copy of it dated May 2011, but I'm sure the original was way, way earlier. I may search through my hard copies when I have the time, but for now I can connect up the veroboard + make waves again!

Thanks, everyone, for your suggestions.
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Old 4th Jun 2019, 2:52 pm   #12
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Default Re: ETI Wave (sound) simulator

..actually, Feb 1996 appears to have the original circuit (referenced in the May 2011 magazine).
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Old 4th Jun 2019, 5:11 pm   #13
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Default Re: ETI Wave (sound) simulator

Quote:
Originally Posted by dave_n_t View Post
The circuit was from Elektor.
dave
[Rueful laugh]

When you first posted this query I went off trying to find your project in ETI but thought I'd kill two birds with one stone by looking out for an ultrasonic mains on/off switch project that I have fond memories of building - it was my first mains powered project and it very nearly killed youthful me, but that's another story.

Anyway, I did find it eventually... in Everyday Electronics, not in ETI, where I was sure it had come from. But you said you had labelled your project as an ETI project, so I kept quiet about that.
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Old 4th Jun 2019, 7:41 pm   #14
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Default Re: ETI Wave (sound) simulator

SiriusHardware,
My apologies for misleading you.



I think what must have happened is that in a previous fit of tidiness, I misremembered + hence mislabelled it; now some more years later, I can't even remember when I labelled it....
dave


Mods: this can probably be closed now.
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Old 4th Jun 2019, 10:04 pm   #15
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Default Re: ETI Wave (sound) simulator

Oh, no harm done.

I ended up finding my old project anyway, which I probably would not ever have done if I had not embarked on your quest initially. I was only admitting that I had, in fact, made exactly the same sort of mistake myself with regard to the project I was looking out for.
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Old 5th Jun 2019, 7:25 am   #16
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Default Re: ETI Wave (sound) simulator

SiriusHardware,
Quote:
Oh, no harm done.
Good!
Strange thing, memory....
dave
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