New stuff...

[Haible Juergen]

Hi Marjan,

	>VCS3 type ring modulator with CA3046

Now that you have posted this circuit, I can finally comment on the EMS 
ringmodulator.

(I had some very fruitful discussions with a former EMS employee before I've
built
my Synthi Clone, and so I feel obliged not to pass EMS circuits on, but
that's
just a personal thing, so I have to wait until someone else does. (;->) )

Now isn't this a fine circuit ? Yes, it looks like the same ordinary 4Q
multiplier
everybody else used (and in fact I have used a 1496 in the synthy Clone),
but
what sets it apart from any other RM I've seen, are the two extra trimpots.
This is more than the usual offset voltage nulling stuff that avoids X or Y
signal
bleedthru. It also compensates for slightly unbalanced circuit parameters,
and
as a side effect, you can cancel the effect of crosstalk between the X and Y
inputs. I have no idea whether these extra pots were necessary because of
badly matched transitor arrays, because of crosstalk from the patch matrix,
or whether it's just an improovement that would give more precision to any
1496-style ring modulator.
I think it's an interesting concept at least.

JH.