Originally Posted by RCruz

The offending zener was replaced and now there is no more "woosh"... both channels sound the same with a very low ripple at full volume...

It seems this component is critical for the "transparency" of the shunt.

With two shunts, I notice a much better transient response and wider soundstage (I believe this is due to the better separation provided by the dual mono setup)

I believe a glass low noise zener with a big Ruby ZLH would make a big difference.

Ricardo