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<font size=3>I just finished building this mixer on a Tellun MUUB-4
PCB. I think rather than build this as a separate module, I'll just
piggyback this on a MOTM-890 uMixer and use the two 'extra' inputs (In-2
and In-4) for the FM mixer inputs. I'm starting to get a bit lazy
and this will give me a nice combo module without much work.<br><br>
PCB photo, scope photos and MUUB schematics at<br>
<a href="http://modularsynthesis.com/modules/DJB-FM/djb-fm.htm" eudora="autourl">
http://modularsynthesis.com/modules/DJB-FM/djb-fm.htm</a><br><br>
Dave<br><br>
<br>
At 09:01 PM 2/11/2006, harrybissell wrote:<br>
<blockquote type=cite class=cite cite="">Hi Tim...<br><br>
ok you asked for it.<br><br>
Its VERY COOL. A must-have imho.<br><br>
It works well throughout the audio range. And don't believe the<br>
BS about the square wave. Use any waves you like.<br><br>
The article warns of 'distortion' but you will LOVE the distortion.<br>
I didn't find a setting I did not like ...<br><br>
I'd set it up with VCAs on the inputs. Overall sound is dead<br>
quiet. I used TL072s and 1% resistors.<br><br>
You can add a cap across the feedback resistor in the output<br>
summer... for HF rolloff. Might be neat to make that switch<br>
selectable.<br><br>
10K inputs are kind of low, a couple of buffer amps are a nice<br>
add. Don't forget to put some series resistor in the output or<br>
the TL072 will go nuts !!<br><br>
BTW... check the schematic carefully. R11 and R4 are in parallel,<br>
so replace them withone 10K instead of two 20Ks<br><br>
H^) harry<br><br>
Tim Parkhurst wrote:<br>
> <br>
> On 2/8/06, harrybissell <harrybissell@prodigy.net> wrote:<br>
> > in the latest issue of Electronic Design (under Design
Briefs)<br>
> ><br>
> > This is an opamp based design... it would be above the ARP<br>
> > 'exclusive or' design but below most true four quadrant<br>
> > designs in terms of functionality.<br>
> ><br>
> > READ the last paragraph... note the schematic says
"rf"<br>
> > but in reality... 'radio frequency' in this design<br>
> > is probably not more than 10KHz :^P<br>
> ><br>
> > Still, some may want to play. I might whip one together...<br>
> ><br>
> > H^) harry<br>
> ><br>
> ************************<br>
> Hey Harry,<br>
> <br>
> Could be interesting. Here's a link<br>
>
<a href="http://www.elecdesign.com/Articles/ArticleID/11935/11935.html" eudora="autourl">
http://www.elecdesign.com/Articles/ArticleID/11935/11935.html</a><br>
> <br>
> The writeup states that the design is 'limited to lower
frequencies'<br>
> which sounds like it would work for audio just fine. Also looks
like<br>
> it works with a variety of waveforms (unlike the square-only ARP
XOR<br>
> design).<br>
> <br>
> Tim (could be interesting) Servo</font></blockquote></body>
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