Baach dsp, true stereo?

There is a Windows software version available for $399 with a 14 day trial. Try it you might like it. It is called u-Bacch and I found it to be worth the investment.

It's in stereo

Did you really need two threads for this?

@jasonbourne52 few

Beatles seem to do have done a lot of LR panning. Didn’t they? As did many other earlier recordings. Center imaging doesn’t seem to be very apparent when this happens.

Let's not forget the Sonic Hologram option Bob Carver added to some of his Phase Linear and Carver preamps/CD players.

Why not do the opposite? The APT Holman preamp had a "blend" control to mix the L + R channels. This would be beneficial for early stereo recordings which had excessive LR panning between channels.