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DIY Stompboxes => Building your own stompbox => Topic started by: g3rmanium on January 10, 2008, 10:59:20 AM

Title: Analog multiplier/squarer fundamental attenuation
Post by: g3rmanium on January 10, 2008, 10:59:20 AM
Hey.

So I bought a frequency generator, hooked it up to my X² squarer (http://johannburkard.de/blog/music/effects/x2-analog-multiplier-squarer-jam.html) and looked at the fundamental and it was more than 35 dB below the squared signal. :icon_eek:

(http://farm3.static.flickr.com/2339/2178266689_e664d64234.jpg) (http://johannburkard.de/blog/music/effects/analog-multiplier-testing-with-my-signal-generator.html)

I guess that is a lot more than your average full-wave rectifier?
Title: Re: Analog multiplier/squarer fundamental attenuation
Post by: Paul Perry (Frostwave) on January 11, 2008, 10:51:17 AM
That is certainly good for a frequency doubler, but a mere 35dB rejection of carrier would not be quiet enough for a ring modulator in general. The question is, can you hear the carrier being swept through the audio band, while there is no input?
It's a battle (layout) to get a really good result.

On the other hand, it's surprising how well some people have done with the traditional transformer & diode ring modulator. But that is far too labor intensive for me, and the transformers limit the carrier range. (the AD633 is happy right down to DC, of course!)
Title: Re: Analog multiplier/squarer fundamental attenuation
Post by: g3rmanium on January 11, 2008, 03:16:30 PM
Quote from: Paul Perry (Frostwave) on January 11, 2008, 10:51:17 AM
That is certainly good for a frequency doubler, but a mere 35dB rejection of carrier would not be quiet enough for a ring modulator in general. The question is, can you hear the carrier being swept through the audio band, while there is no input?

It's a multiplier, not a ring mod. :-)

Quote from: Paul Perry (Frostwave) on January 11, 2008, 10:51:17 AM
(the AD633 is happy right down to DC, of course!)

I saw that, too. Swept all the way down to 10 Hz or so and got 20 Hz out.
Title: Re: Analog multiplier/squarer fundamental attenuation
Post by: Paul Perry (Frostwave) on January 12, 2008, 08:02:21 AM
Yeah, I know it's a multiplier. Now play a chord through it. :icon_wink:
Title: Re: Analog multiplier/squarer fundamental attenuation
Post by: g3rmanium on January 13, 2008, 05:07:28 PM
Quote from: Paul Perry (Frostwave) on January 12, 2008, 08:02:21 AM
Yeah, I know it's a multiplier. Now play a chord through it. :icon_wink:

Done (http://johannburkard.de/blog/music/effects/x2-analog-multiplier-squarer-jam.html).  :icon_twisted:
Title: Re: Analog multiplier/squarer fundamental attenuation
Post by: Paul Perry (Frostwave) on January 14, 2008, 09:10:55 AM
Nice clip, Johann!
Now I will have to add a switch to my ring modulator, to convert it to a squarer  :icon_wink:
Title: Re: Analog multiplier/squarer fundamental attenuation
Post by: g3rmanium on January 14, 2008, 09:11:53 AM
Quote from: Paul Perry (Frostwave) on January 14, 2008, 09:10:55 AM
Nice clip, Johann!
Now I will have to add a switch to my ring modulator, to convert it to a squarer  :icon_wink:

The world clearly needs more octave-up. :icon_idea:
Title: Re: Analog multiplier/squarer fundamental attenuation
Post by: oldschoolanalog on January 14, 2008, 10:34:57 AM
Quote from: g3rmanium on January 14, 2008, 09:11:53 AM
The world clearly needs more octave-up. :icon_idea:
;D ;D ;D