Phase inverting problem

Thanks for the responses.

Can I tell? No, actually I don't. But I just want to do it as correct as I can. You never know. i don't want to find out in five years I've been listening to a sound that could have been a lot better.

Almarg makes a god point - the phono stage does go through the line stage. I don't have a manual, and on the manufacturer's site it just says: "Line Stage phase inverting, Phono Stage phase correct" which sounds pretty ambiguous to me. I've sent them a mail. unless someone here knows the Conrad-Johnson PV12a and knows what it does?

Why does it hum when reversing the wires? No idea. I use a Technics SL1200MK2 with standard tonearm, if that helps. I see a black ground wire going in the bottom of the tonearm, but I don't know where it is connected to. I suspect the ground is connected to the inside of the tonearm (I can't check since the outside of the tonearm isn't conductive). The green wire (R-) is connected to the cartridge body, I can see that. But as far as I can make out, the cartridge body is not connected to the tonearm / ground. I can't figure out why switching the red/green and blue/white would cause a big hum, but it does.

Half of all media are phase incorrect anyway, so you will still have a signal out of the speakers that's incorrect in phase (polarity) half the time whether the system is phase/polarity correct. There is no standard for polarity in media.

Cheers

This is simple:

1- Your PV-12A is phase inverting. Reverse the red/black connections on the back of EACH speaker. DO NOT try reversing ICs.

2- Your phono stage is phase correct - so leave the cartridge headshell leads alone (wired normally).

FWIW, I used to own a PV-12L and couldn't tell a big difference whether the speakers were wired in or out of phase. I believe that Magfan is correct - your recordings are going to be both in and out of absolute phase; sometimes from track to track. My advise is to listen to your system connected both ways, see which one works best for you, then leave just it alone.

The only way you are going to be able to hear absolute phase is if the recording is done with 2 microphones only.

The vast majority use more than this. As soon as other phase relationships are introduced by any additional mics, the delicate information that allows you to hear absolute phase is destroyed.

On top of that, as pointed out earlier, 1/2 of your recordings are out-of-phase anyway! Unless they are done with 2 microphones, you will not be able to sort out which ones are which.

While I would quibble about Atmasphere and Geofkait's 50% figure as just a guess that recording engineers are largely indifferent to absolute phase, I would say that with the capability to change absolute phase, I hear very few instances where there is a clear choice. Nevertheless, I understand the nagging concern about having both vinyl and digital in the same phase. It is common for each stage of amplification up to the amplifier itself to invert.

I even went so far once to install double pole/double throw switches on my speaker wires to allow switching of absolute polarity there.