[sdiy] On the topic of ring modulation (Using FETs instead of diodes?)

[Terry]

Ooops!
Forgot the video link.
http://youtu.be/NM7PCrvHpnw

The Moog style frames are completly hand made. Saw, file, even the plexi  
standoffs. Assembled with L brackets.

> Just built a DIY germanium diode ring modulator. Had to match the diodes  
> and use good quality audio transformers. Used Edcor WMS10K-10K  
> transformers, listed at 20-20,000Hz frequency response. Sounds really  
> nice to my ears and built with all discrete parts. Added a discrete Moog  
> CP3 type after the ring modulator to bring the ring audio level up.
> Pics of the build:
> http://i62.tinypic.com/25r0d3m.jpg
> http://i62.tinypic.com/2ldiyo9.jpg
> http://i58.tinypic.com/zxn18n.jpg
>
> Put a video up to demo the sound of the germanium diode ring modulator.  
> I think it sounds really sweet. Might be the higher quality transformers  
> used. Can hear in the video when I unpatch either source the  
> bleedthrough is minimal. An interesting quality I noticed was the  
> carrier input, (the one that goes to the center taps on both  
> transformers) has a lag. Can see at one part of the video when I change  
> the square wave to pulse, it lags behind on the scope shot.
> Best sounding DIY module I ever made, sounds like magic.
>
> There is an article written by Harold Bode describing his ring modulator  
> in the first issue of the Electronic Music Review from the Moog  
> Trumansburg days. He mentions some of the differences between the  
> switching-type and  mulitplier-type ring modulators. Starts on page 9,  
> good read from the old days.
> Link here:
> http://www.ubu.com/emr/periodicals.html
>
>>> As mentioned in the video, the diode ring mixer has the issue that
>>> there are dead spots when the carrier is near zero, because of the
>>> diode turn on threshold. This got me thinking, what if you instead
>>> used FETs, perhaps driven by a comparator, instead of diodes? This
>>> should, if done well, get rid of that non-linearity, as far as I can
>>> tell.
>>
>> Indeed, the dead spots are the major reason that the diode ring  
>> modulator doesn't sound very good.  The diode nonlinearities are also a  
>> problem.
>>
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