EMS VCS3 Ring Modulator - how does it work?

[<<marjan>>]

Sean Costello wrote:
> 
> Hi everybody:
> 
> Anyone know what is inside the VCS3 ring modulator?  I've never seen a
> circuit.  Is it a transformer based design, or discrete transistors, or
> a 1496 design, or...?

It uses IC TAB 101 ,2c764 tranny pair and few discrete transistors.
TAB is four (matched ?) transistors but note with schematics that
in later models it has been replaced with 2c746,early ones with
matched bc 169c (?).I guess you can use 3046 instead. 
Schematic looks like the one on tomg's site but with some transistor
input stages and current source and few trimers more,
9 npns and one pnp in all.
Reminds me on discrete 1496 rm if memory serves me.





marjan