[sdiy] improved dynamic range diffpair-vca

[JH.]

>Yes, but considering the configuration the distorsion will be the killer
>anyway

You set an amount of distortion that you consider tolerable.
This results in a certain signal level on an ordinard differential pair.
That level, divided by the noise of the pair, is the SNR.

With the proposed circuit, and the same amount of distortion, you can have 
twice the signal level.
And you'll get SQRT(2) times the noise.
Resulting in 2 / SQRT(2) = SQRT(2), or 3dB,  SNR improovement.

If this is true, it's true for any amount of distortion you choose.

JH.