Modwright SWL 9.0SE Preamplifier

Can I ask why it inverts the phase in the 1st place?

Seneca it is more sonically advantageous to have a circuit that inverts phase because it is a simpler circuit requiring more attention to circuit design. On the other hand a circuit that does not invert phase has extra sound-degrading circuitry. Many quality preamps for this reason do invert phase.

Dan Wright tells me that inverting phase is a natural consequence of a more purist (straight wire with gain) type of implementation with tubes stages. Dunno....lots of tube preamps do I guess. I believe Dan feels that an invert phase switch adds unnecessary switching/noise in the signal path. No big deal, really.

I believe one tube stage inverts the phase, and to have it revert back to the original phase in would take another stage (add'l cost, and add'l devices in the signal path) to correct.

Keep it simple, is what Modwright and various other mfgs wisely chose to do.

There are those that believe switching the speaker leads is better than using an electonic switch. Re: Tedmbrady's point about so many lines may be out of phase that phase reversal may be a moot point, well it depends on the recording. With that in mind, I have always wondered why so many pre's that tout the superiority of their dual mono designs don't include individual phase switches for each channel? Perhaps in the digital future it could be done automaticaly?