2. amps-preamps
  3. 150682-134280

Impact of phase inversion by preamp

This will be my first post on this forum so I thought I’d pose a question I’ve always wondered about.  I have a Conrad Johnson Premier 18LS preamp that I’ve been extremely happy with since first acquiring it some years ago.  This is a solid state single ended, single stage design that inverts the phase of the input signal at the output.  The manual states that you should reverse the connections to the speakers to account for this.  Obviously this is easily done but I really can’t see how it would really matter as long as things are connected consistently between the left and right channels.  I’d be interested to hear what others have to say on this subject.
ligjo
ligjo OP
7 posts
 
Thanks for the replies guys!  There are no polarity reversal switches in any of my gear so I need to make the changes at the speaker terminals, making quick AB comparisons difficult.  I suppose when in doubt, follow the manufacturer recommendations which is what I do.  Just curious whether it really matters.
verdantaudio's avatar
verdantaudio
1,463 posts
 
I have found that when the phase is inverted that bass will sound hollow or will be missing a bit.  Some speakers seem to be more impacted by this than others.  I can definitely hear a difference in mine. 
georgehifi's avatar
georgehifi
10,312 posts
 
Easiest way to think about it
Is if phase correct the bass drivers initial movement on a note, is forward into the room, thus pushing your eardrum inwards.
The opposite happens if your system is inverted.

Cheers George
paulcreed
534 posts
 
I agree with verdant there is a change in bass and detail in my system and very noticeable. I have a Bruce Moore Preamp that recommends reverse polarity which I do. I have a invert phase switch on phono pre with a remote so I can switch from my chair. So I can A/B fast. I find I use the switch a lot it's crazy because I have it switched at the speaker. Different songs sound better on the same album with the switch on and off, so for me there is no right answer whether to use it or not. I do find I use the switch off with polarity reversed 2/3 of the time maybe.

jond's avatar
jond
5,660 posts
 
I wish I had a phase reversal switch on my preamp so many recordings vary in terms of correct or inverted phase.
More to discover