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Phase Inversion in Preamplifer?

I just bought a used Audible Illusions 2D here on a'gon. This will be my first venture into separates. I've learned that AI preamps have inverted phase, so it's recommended that I switch +/- polarities at the speaker-amp hook-up. OK. But according to AI literature the phono stage of the preamp is NOT inverted, only the output stage is. So, since I listen to both vinyl and CDs, what do I do? Should I reverse speaker wire polarity or not?

Incidentally, the amp I'll be using is an ATI 1502 -- still haven't been able to find out if it inverts polarity or not. But based on my (limited) research thus far it appears that phase inversion is a design of preamplifiers more than power amplifiers. Is that right?

Thanks,
Rich
winegasman
phd
1,301 posts
 
Clio09, a test CD to make phase corrections is a very good investment. If there are no other components in your system inverting phase other than the preamp than reversing polarity on both of your speakers will correct this. I am just saying it is difficult to hear the difference if this is the case. Good deal.
sugarbrie
3,854 posts
 
If your system is phase correct, playing music recorded out of phase will not change the phase of your system. If not a mistake, they may have recorded it out of phase to create the sound they wanted when you play it back, that is all. Grooves on an LP or digital code on a plastic CD cannot invert the electrical signal going through your system or add a gain stage to your preamp. You are playing the sound of something out of phase on a system in phase, that is all.

If your CD player has a polarity switch, not sure if it really corrects it or just makes it something else. I have such a CD player and that owners manual says it reverses polarity, NOT to be confused with inverting the phase.

A way to have fun with phase is to play the same signal through both speakers (use bookshelf speakers). Reverse the speaker wires on only one speaker. Now place the two speakers together face to face. It won't be a perfect seal, but if perfect the sound volume would go away (or in your case it would be greatly reduced). This is because the two speakers are playing the same sound 180 degrees out of phase with each other. They will cancel each other out creating silence.

This is similar to the experiments they do to try to make luxury automobiles quieter. They play the frequencies of road noise out of phase to cancel out the actual road noise, making it quieter inside the automobile.
benie
147 posts
 
The way it was explained to me is if the preamp is inverted one must switch speaker leads + - at either amp end or speaker end. But because of the possiblity of the amp being inverted one must try both ways. Taking some tracks with good vocals, the proper way will show more Depth on the vocals. I was able to notice this but it wasn't a big difference but it was there. In this hobby it is about getting the small gains and not costing anything is a Bonus.
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