Topic: Tube preamp question

[scervin]

Looking at picking up a tube preamp with HT bypass.  How are others handling the phase inversion issue.  I could easily switch the connection at the speaker terminals, but then wouldn't this mess with my MC and HT phase when using the bypass?  I don't want to always switch connections.

SC

[dmonterisi]

sorry i don't have any info for you, but curious what the phase inversion issue is? 

[scervin]

sorry i don't have any info for you, but curious what the phase inversion issue is? 

Some people are sensitive to phase and i will be testing that today.  The tube stage will invert the phase 180 degrees.  So for my receiver output will be 180* out of phase from the tube preamp.  If I were to switch the speaker leads to correct for one, I'd be messing up the other.  While I probably wouldn't notice much on the movie side, having 3 speakers in phase and 2 with inverted phase may be an issue with SACD and DVD-A.

[scervin]

Have done some research this morning on the phase issue.  Seems that 50% of recordings are one way or another in absolute phase.  I also did a little switching in the system myself and can't find a huge difference in sound.  To me I think I can hear a difference, but wondering if it is really there. 

[Invisible]

If the preamp you are looking at does invert, in my opinion it is best to switch your speaker leads for optimum performance. Many people say that if the recording was not made in "absolute phase" that it does not matter. In all of my testing though, there is an audible difference if running an inverting pre without switching the leads. Also, I find that it is best to do this at the speaker itself.

What unit are you currently looking at if you don't mind me asking?

[scervin]

If the preamp you are looking at does invert, in my opinion it is best to switch your speaker leads for optimum performance. Many people say that if the recording was not made in "absolute phase" that it does not matter. In all of my testing though, there is an audible difference if running an inverting pre without switching the leads. Also, I find that it is best to do this at the speaker itself.

What unit are you currently looking at if you don't mind me asking?

That's just it, I don't plan to switch when I want to watch a movie or listen to MC music.  Anyone have any ideas on a phase inverter?  What were all you CJ folks doing?

I'm looking at the Modwright 9.0SE and Odyssey Candela.

[Invisible]

Are both of the units you're looking at inverting? I have no personal experience with either.

[Lil Kim Jong-Il]

What were all you CJ folks doing?

Leads swapped at the speaker terminals. 

But I'm running just two channel.  I not sure if the phase inversion occurs in theater passthrough mode.

[carlbeck]

I dealt with phase inversion for a few years & something was never "right" in my system. I had my leads switched at the amp instead. One day just for giggles I decided to switch at the speakers & it was like night & day. I could tell a difference for sure, everything just snapped into place. Now, I can't imagine dealing with phase inversion, I just can't do it, it's that important to me. Plus the fact that I am a total nerd 

[scervin]

I dealt with phase inversion for a few years & something was never "right" in my system. I had my leads switched at the amp instead. One day just for giggles I decided to switch at the speakers & it was like night & day. I could tell a difference for sure, everything just snapped into place. Now, I can't imagine dealing with phase inversion, I just can't do it, it's that important to me. Plus the fact that I am a total nerd 

So do you switch on the fly?  This topic has been driving me bonkers the last couple days and with all the searching, I've found the phase is not the same on all discs or tracks for that matter.

I did a little testing and found an audible difference on a few vinyl pressings, but not on CD's.  I thought about just changing the leads on the phono cartridge to make it "correct" if a tube preamp were put in the system.  I'll let you know where I end up, but I'm keeping my eye out for a Modwright SWL 9.0se in black.  Klaus at Odyssey gave me a heck of a quote on a Stratos Extreme 3 channel and Candela tube pre so I might got in that direction.

SC

[carlbeck]

Nope, I am two chanel only. My point was though that until I switched at the speakers it never sounded correct. It should have been fine when I switched at the amp end but it wasn't. I also had a CJ pre-amp back in the day, my first tube product & that taught me about phase inversion. I have since switched a bunch of stuff around (of course) & now have a Mod Wright which also inverts phase. For me it is all about imaging for music, I could probably deal with it for HT but not "real" music. I would set my system up for the best possible music reproduction by switching leads at the speaker & dealing with phase inversion for movie soundtracks. Honestly who cares what side of the room the bomb explodes in 

[scervin]

Nope, I am two chanel only. My point was though that until I switched at the speakers it never sounded correct. It should have been fine when I switched at the amp end but it wasn't. I also had a CJ pre-amp back in the day, my first tube product & that taught me about phase inversion. I have since switched a bunch of stuff around (of course) & now have a Mod Wright which also inverts phase. For me it is all about imaging for music, I could probably deal with it for HT but not "real" music. I would set my system up for the best possible music reproduction by switching leads at the speaker & dealing with phase inversion for movie soundtracks. Honestly who cares what side of the room the bomb explodes in 

Actually the absolute phase should not impact the placement of instruments or sounds.  Instead the drivers move in then out as opposed to out to in (180 degree invert of sine wave).  Swapping channels in music is less critical than doing it for movies.  I once realized I had swapped channels when the phone rang on the right side of the screen and the actor picked it up on the left.  Gotta a good laugh out of it.