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fredw
Joined: Jul 08, 2007 Posts: 10 Location: Berkeley, CA
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Posted: Sun Jan 25, 2009 1:46 pm Post subject:
Sonic Multiplier Subject description: Sine wave oscillator doesn't work yet |
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I've build the Sonic Multiplier (ring modulator) kit. The sine wave oscillator doesn't work yet. The control voltage inputs (fine and coarse) from the front panel work, but no oscillation. I've inspected the board carefully, and double-checked all part values. I'm not sure how to troubleshoot an oscillator. It's a stage variable filter that's supposed to oscillate. Anybody have any ideas how to troubleshoot this?
Thanks much! |
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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fredw
Joined: Jul 08, 2007 Posts: 10 Location: Berkeley, CA
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Posted: Sun Jan 25, 2009 2:18 pm Post subject:
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[quote="RF"]Ray has a note on the schematic about changing R46 if you are using 15 Volts...
Wow that worked! Thanks much for the quick and correct reply! I changed it to 47k and now it oscillates. The output is a trapazoid instead of a sine. I put a 100k pot there instead and now I can vary the shape until it's a nice looking sine wave.
Thanks again, Fred. |
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Skrog Productions
Joined: Jan 07, 2009 Posts: 1196 Location: Scottish Borders
Audio files: 155
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Posted: Mon Jan 26, 2009 10:21 am Post subject:
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Hi, i use 12v +/- and had the same problem, i hooked up to my scope and the output of the sine was very low, i first thought it might need more gain but it was the filter needing kickstarted into self ocsillation, had me stumped for a couple of hours, works fine now. |
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tommi
Joined: Dec 05, 2007 Posts: 247 Location: Italy
Audio files: 3
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Posted: Sat Jun 13, 2009 2:35 am Post subject:
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Hi,
I am testing the Sonic Multiplier that I have built tonight.
Both the two preamp sections and ring modulation section are working.
I got no internal sine. Listening from the sine out all I can hear is a tiny sound just wich seems a filter when resonance is turned just before starting self oscillating..
I am running on +/-12V and I checked all resistor values...
Any suggestion?
tommi _________________ http://soundcloud.com/mister-vommi
http://tideofsound.net |
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tommi
Joined: Dec 05, 2007 Posts: 247 Location: Italy
Audio files: 3
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Captain Biscuits
Joined: Jun 11, 2010 Posts: 116 Location: Northampton, UK
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Posted: Fri Mar 18, 2011 4:33 pm Post subject:
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Thanks for that Tommi. I've just finished my ring mod and all was fine except for the sine wave output. Just changed R46 to 100K and it's working perfectly.
I was slightly puzzled when I came to adjust the trim pot. I couldn't detect any bleed through at all. Turned out it just happened to be adjusted perfectly before I started fiddling with it.
Nice, once again, to have a problem, search electro-music and find a solution within minutes.
Much appreciated!
Cheers
Ian |
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littlem4tt
Joined: Jun 30, 2013 Posts: 44 Location: uk
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Posted: Sun Jul 07, 2013 2:48 pm Post subject:
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omg i have been struggling with this for ages. I even built it on breadboard a few times. I cant wait to try this mod. |
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littlem4tt
Joined: Jun 30, 2013 Posts: 44 Location: uk
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Posted: Mon Jul 08, 2013 6:00 pm Post subject:
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So the moment came to replace r46 to 100k connect the scope turn on and...
whoooooop! lovely 8v p/p sine wave!!!
you guys are the best!!
many thanks |
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potpourri
Joined: Nov 15, 2013 Posts: 1 Location: ohio
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Posted: Fri Nov 15, 2013 1:20 am Post subject:
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I lowered the resistor value of R46 to 50k for a wider frequency range. I Hope I don't learn to regret it. |
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