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camelneck
Joined: Sep 27, 2008 Posts: 68 Location: KY (USA)
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Posted: Thu Mar 19, 2009 2:41 am Post subject:
Bridechamber's Matched Transformer and Diode Set |
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When I bought my Wave Multiplier PCB set from Bridechamber, I also purchased the Matched Transformers and German Diode set for the real Ring Modulator in this particular project.
When I was installing the diodes, I noticed that the diodes were "gold-doped diodes" instead of "germanium diodes". I also measured the forward voltage drop for each of these diodes and although all 4 diodes were equally matched, the forward voltage drop was 0.66 volts, which is consistent with gold-doped diodes, and not the 0.25 to 0.3 volts that one would find when measuring the forward voltage drop of a germanium diode.
There is a note on the PCB that says to use germanium diodes for the ring of the Real Ring Modulator. So I'm sure that this will effect the overall sound of the real ring modulator and its associated distortion.
Did anyone else who purchased this Transformer+Diode set from Bridechamber also get gold-doped diodes? How did this effect the overall sound?
David |
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v-un-v
Janitor
Joined: May 16, 2005 Posts: 8933 Location: Birmingham, England, UK
Audio files: 11
G2 patch files: 1
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Posted: Thu Mar 19, 2009 4:21 am Post subject:
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Hi David.
I really don't think you will notice much difference. I built a RM circuit using modern diodes, and comparing to a friend who built one using germanium diodes, there really wasn't any difference in sound.
You can really get hung up on this kind of stuff- like using coaxial cable for interconnects etc, but it makes little difference.
Tom _________________ ACHTUNG!
ALLES TURISTEN UND NONTEKNISCHEN LOOKENPEEPERS!
DAS KOMPUTERMASCHINE IST NICHT FÜR DER GEFINGERPOKEN UND MITTENGRABEN! ODERWISE IST EASY TO SCHNAPPEN DER SPRINGENWERK, BLOWENFUSEN UND POPPENCORKEN MIT SPITZENSPARKSEN.
IST NICHT FÜR GEWERKEN BEI DUMMKOPFEN. DER RUBBERNECKEN SIGHTSEEREN KEEPEN DAS COTTONPICKEN HÄNDER IN DAS POCKETS MUSS.
ZO RELAXEN UND WATSCHEN DER BLINKENLICHTEN. |
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camelneck
Joined: Sep 27, 2008 Posts: 68 Location: KY (USA)
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Posted: Thu Mar 19, 2009 11:33 pm Post subject:
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>>I really don't think you will notice much difference. I built a RM circuit using modern diodes, and comparing to a friend who built one using germanium diodes, there really wasn't any difference in sound. <<Tom>>You can really get hung up on this kind of stuff- like using coaxial cable for interconnects etc, but it makes little difference. <<
You're absolutely right. That's a very good point.
The same applies to VCO waveforms. Often, the waveform don't have to look like a perfect triangle wave on an oscilloscope to sound like a perfect triangle wave. It doesn't matter that much to our ears. However, there may be other applications, including non-music applications where you might need a signal generator to produce a near perfect triangle wave in order for the equipment to function properly.
However, you have to remember that engineers like myself, are trained to scrutinize even the most minute details until we are sure that they have no impact on the circuit. In other words, we are trained and paid to be "anal".
Consider the case of the CGS Wave Multiplier vs the YuSynth/JH Wave Multiplier. Although the circuits are quite different, both depend upon diode rectifiers to do the "wave folding". However, the BOM for the YuSynth WM calls for matched diodes while the CGS WM calls for regular diodes. Although the waveforms produced by the YuSynth Wavefolder may look more symmetrical due to the matched diodes, apparently both WM's do a fairly good job of mangling the original waveform and the sound.
So, I'll trust your ears and go with the diodes I bought, at least for now.
Thanks again for your post.
David |
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Rykhaard
Joined: Sep 02, 2007 Posts: 1290 Location: Canada
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Posted: Fri Mar 20, 2009 7:59 am Post subject:
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Hey - I wish I'd thought to post this question earlier.
As per transformers for the 'real ring modulator', the other day when I was scrapping some old equipment I'd rescued from the trash at work, I took out from a control board's PCB a pair of miniature transformers. The only way that I could 'match' them, were by the # atop of each of the transformers. (There was a total of 4. 2 each having the same #'s.)
Now, I haven't an LCR meter to measure each of the coil's Inductances on the transformers. Measuring each of them for resistance, both sides of each come out to your standard 0.02 ohms (test lead resistance).
Each of transformers (1/2" x 1/2" x 1/2") have 2 leads to one coil and the other is center-tapped.
Outside of that - I've NO other clue about them. What the PCB / enclosure was from or what it is. (Possibly came from early surface mount machinery; parts placement VCD machine or something.)
What parameters do I need to know / worry about, for the 'real ring modulator', as far as the transformers go? Do the coils have to be somewhat matched on each side of the transformer, or a certain ratio to each other?
Or should I just hook them up with my 1N34A germaniums and see what happens?
Thanks for any thoughts. (I'm not an Eng. I'm self-taught in everything.) |
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v-un-v
Janitor
Joined: May 16, 2005 Posts: 8933 Location: Birmingham, England, UK
Audio files: 11
G2 patch files: 1
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Posted: Fri Mar 20, 2009 10:27 am Post subject:
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Go for it Rych! _________________ ACHTUNG!
ALLES TURISTEN UND NONTEKNISCHEN LOOKENPEEPERS!
DAS KOMPUTERMASCHINE IST NICHT FÜR DER GEFINGERPOKEN UND MITTENGRABEN! ODERWISE IST EASY TO SCHNAPPEN DER SPRINGENWERK, BLOWENFUSEN UND POPPENCORKEN MIT SPITZENSPARKSEN.
IST NICHT FÜR GEWERKEN BEI DUMMKOPFEN. DER RUBBERNECKEN SIGHTSEEREN KEEPEN DAS COTTONPICKEN HÄNDER IN DAS POCKETS MUSS.
ZO RELAXEN UND WATSCHEN DER BLINKENLICHTEN. |
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BananaPlug
Joined: Jul 04, 2007 Posts: 307 Location: Philly
Audio files: 5
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Posted: Fri Mar 20, 2009 5:47 pm Post subject:
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You might get a chuckle out of this. The National Library of Australia lists a book in their catalog titled:
"Miniwatt" transistors geranium diodes & silicon diodes"
http://nla.gov.au/nla.cat-vn2942371 |
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24081 Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320
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Posted: Fri Mar 20, 2009 6:03 pm Post subject:
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BananaPlug wrote: | geranium diodes |
o i love that use it myself at times.
Geranium diodes with silicon flowers. _________________ Jan
also .. could someone please turn down the thermostat a bit.
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