[sdiy] Ring Modulators with Zener Rings.

[Magnus Danielson]

Alfred,

The NIST Time and Frequency research folks have developed their own 
double-balanced mixer using of the shelf 1:1 transformers and 2N2222A 
transistors (Base and Collector tied together). The 2N2222A transistors 
was actually a chip of them, so they already had a good thermal 
coupling. This cheap mixer was competing against mixers for several 
thousand dollars. The one thing different for audio use would be the 
choice of transformers, as lower frequencies will saturate the RF 
transformers NIST was using.

I think that it was A 4096 used, but I have not got that confirmed, will 
ask.

Happy hacking!

PS. Go to NIST T&F page, publications and search for Craig Nelson as 
author and you will find the paper.

Cheers,
Magnus

On 04/21/2016 01:39 AM, alfred.pear at gmail.com wrote:
> Hi All -
>
> I was just experimenting with Ken Stone's "Active Ring Modulator"
> design, substituting different groups of diodes (still matching them,
> more or less, by hand)...
> I'm curious what sorts of results people get with different diodes. The
> design suggests germanium or schottky - I'm not sure what the advantage
> of one over the other is.
>
> I also experimented with some 5.1 zener diodes and it didn't seem that
> different from a non-zener..any ideas?
>
> -AP
>
>
>
>
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