Will preamp manufacturers tell you if the model is phase inverse?

I just heard back from Nick at Rogue. The RP-1 and the RP-5 Both invert phase on ALL inputs (including phono).

 

So Rogue told you the RP1 inverts both line and phono, but JA's measurements in Stereophile showed that the phono does not invert?  Seems odd to have a manufacturer give you the wrong specs.

although phono stage preserved absolute polarity and line inputs stage inverted absolute polarity, the preamp output still inverted absolute polarity!

Remember that you want to take the entire amplification chain into account. So (for example) if you have:

• Phono stage (non-inverting)
• Line stage (inverting)
• Amplifier (inverting)

Then your signal path is non-inverting.  With multiple sources, you might have one source which results in an inverted signal and another that does not.

Cheers,
Thom @ Galibier Design

You can't just invert a single ended cable. :)

You can't just swap the leads, because the outer conductor is almost always ground. You'll just end up with ground on the center, and ground on the ring.

This would work for truly balanced inputs, which are very rare in RCA inputs.

Best,

E

Why not switch the input leads at the amplifier instead of the speakers? Is there anything wrong with this approach?

@kalali that would just swap left and right, not phase. Swapping phase involves swapping the signal and ground wires within each cable..