Ring modulators / some comments

Martin Czech martin.czech at intermetall.de
Wed Nov 17 08:36:33 CET 1999


:::At 10:37 16.11.99 +0100, Martin Czech wrote:
:::>btw.
:::>
:::>the audio transformers for a real ring mod are not quite cheap.
:::>Farnel carries some, about 10 EURO each.
:::>The basic passive circuit needs tree.
:::
:::Or two. Like the circuit from synthfool.

I was refering to the old days (1950 or so), they used three.
Maybe just for impedance matching, lower amplitude with no 
power loss, thus less noise.

:::If one uses transformers with two secondary windings, one can add a 
:::small trimmer to adjust the mismatch of the two windings. 

This was not the point. The amplitude must be very small, otherwise you will
get severe feedthrough which can't be trimmeda t all (at least
this is what I found out).

:::Or the (Ge) AA112 which was used a lot in AM-tuners. 
:::Just a weird idea: What about using vacuum tube diodes. i.e. use two dual
:::triodes and tie the grid to the anode. They've got very soft knee.

I don't know is such a characteristic would be desireable.
Four nonlinear elements , that's pretty complex. I guess one
has to solder or simulate. So far I used only Ge or Si.


m.c.




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