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soundforger
Joined: Jun 24, 2011 Posts: 20 Location: The Netherlands
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Posted: Thu May 02, 2013 3:49 am Post subject:
ua726 Subject description: Does anyone know know a replacement? or a way around it? |
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I want to build a few (Formant) VCO's, but I can't get my hands on UA726's.
Does anyone know a replacement, or a way around it? Can I use matched transistors with a tempco? My knowledge of electronics is limited, so very complicated design modifications of the schematic of the VCO may be a little to much for me, unless you explain it to me as if I were a six-year-old. . |
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soundforger
Joined: Jun 24, 2011 Posts: 20 Location: The Netherlands
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Posted: Thu May 02, 2013 3:51 am Post subject:
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The Formant was published around 1980 when I was 20 or so. Back then I didnt have the money for the project. I do now, provided that the parts I need are available... |
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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Posted: Thu May 02, 2013 1:17 pm Post subject:
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Ah .. didn't have the money either at that time .. later bought a formant built by someone else .. very cheap at that time ... payed like 200 Euro for it (although the build quality is not great).
Not knowing the answer I googled a bit ... and now remember that the µa726 was used for heating too.
Technically it should be possible to change it for a matched pair indeed and a tempco would certainly be a good idea then ... best bet probably would be to find similar designs and copy from that a bit.
BTW .. a lot of 741's were used in the Formant, I'd replace those for something more modern .. the Formant is a bit noisy in parts as is. _________________ Jan
also .. could someone please turn down the thermostat a bit.
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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oneoff
Joined: Nov 23, 2008 Posts: 46
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Posted: Fri May 03, 2013 5:28 am Post subject:
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I still have 2 pcs. UA726 NOS , the originals
Golden pins , they are still in a plastic wrap .
Please send a PM if you're interested.
Cheers
Oneoff |
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soundforger
Joined: Jun 24, 2011 Posts: 20 Location: The Netherlands
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Posted: Sun May 05, 2013 5:34 am Post subject:
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@ Blue Hell:
I'll check out some datasheets to see what I can use instead of the 741's.
Thanks for the link. Yes, I know this one. I read the blogs of Rick Jansen, Michel van Osenbruggen, Klaus Pohlig and Bruce Bates. And I have the books by Chapman and Aigner.
@ oneoff
Thanks for the offer! I just pmd you. The formant uses 1 ua726 per VCO and I want to build 4 or 5 of them. This would mean a great start, because I dont have to change the original schematic and pcb.
If anyone else wants to part from these parts, I would be more than happy to buy them!! |
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