[Birdbrain]

I see that the phase inverter option is available in the new AvaStar preamp. Is this an option on the Insight SL or EC preamps?

[oneinthepipe]

Yes, the option is 199.00 when ordered with a new preamp.  The retrofit cost is slightly higher.  I don't think that a phase inverter board and a phono board can both be installed because of physical space requirements.

[boycephoto]

I have an Insight+ EC with phono and phase inverter options.  A nice musical insturment!

Dave

[Birdbrain]

Thanks, fellas.

[taoggniklat]

For the un-edumacated, what does this accomplish?

[oneinthepipe]

The phase inverter can be used to bridge (run in mono) two identical amps, tripling the power of solid state amps and doubling the power of tube amps, and with a single amp, can be used to reduce power supply drain and residual inter-channel crosstalk.

[doug s.]

The phase inverter can be used to bridge (run in mono) two identical amps, tripling the power of solid state amps and doubling the power of tube amps, and with a single amp, can be used to reduce power supply drain and residual inter-channel crosstalk.

huh?  since when does phase inwersion have anything to do w/this?  or, is the ava phase inwersion different than the standard phase inwersion i am aware of?  amps can be bridged or not, regardless of whether a preamp can inwert phase, if the amp architecture allows it.  and, i am baffled how phase inwersion can reduce p/s drain & cross talk.

my preamp (not ava) has phase inwersion, and, to be honest, i find it completely useless, as i have no idea what phase any of my software is, and even on a single recording, the phase may be different from one cut to the next.

ymmv,

doug s.

[turkey]

huh?  since when does phase inwersion have anything to do w/this?  or, is the ava phase inwersion different than the standard phase inwersion i am aware of?  amps can be bridged or not, regardless of whether a preamp can inwert phase, if the amp architecture allows it.  and, i am baffled how phase inwersion can reduce p/s drain & cross talk.

my preamp (not ava) has phase inwersion, and, to be honest, i find it completely useless, as i have no idea what phase any of my software is, and even on a single recording, the phase may be different from one cut to the next.

ymmv,

doug s.

There are regular outputs and inverted outputs, and they operate simultaneously. What you're talking about is an either/or flipflop of phase.

You can bridge an amp by feeding one channel of the amp an in-phase signal and the other out-of-phase. The outputs then sum when you connect the speaker across the two hot terminals. You're turning one stereo amp into a bridged mono amp. (Some amps don't work with this if they don't have a common ground for their outputs.)

Or you can feed one channel of an amp L-channel in-phase and the other channel R-channel out-of-phase (or vice versa) and then reverse the phase of one of the outputs by flipping the speaker wire. That gets you more power out of your amp because one channel sees a positive-going signal in the bass while the other sees negative-going. They're hitting opposite sides of the power supply, so an entire filter bank is essentially serving one channel at a time.

Frank can probably explain it better, or point you to the issues of Audio Basics where he explained it.

[doug s.]

thanks, turkey - i got it.  yes, i was thinking of a switch, not two separate simultaneous phase-inwerted outputs.  my preamp has that, as well; i have never used it, either.  my pre feeds an active x-over for bi-amping or tri-amping, depending on speakers...

doug s.

[modular747]

Having a switch to reverse the phase of the outputs is useful only to correct mis-wired, out of phase speakers without having to change the speaker wires.

It's also used be some who "believe in" absolute phase - i.e. there is an audible difference whether both speaker diaphragms start moving towards or away from you. (Since there is no standard way absolute phase is recorded and there has never been any objective evidence that anyone can hear the difference, there's not much point.)

For the purposes Frank is using phase inversion, a switch is of little use and only adds a source of error, noise or failure.  These are set-em and leave-em.  When bridging, you don't want to change - that will only null the output. 

[rollo]

I could not disagree more sorry. some people like myself can call the correct phase when music is played. All recordings are not recorded in phase. A wonerfull option IMO. One that stopped me from buying particular components.
  For me I like it in the source say phono stage or DAC.  Ever notice the music favoring one channel on CDs as opposed to others. Boomy bass as oppossed to focused and tight. Exaggerated sibilance on female voice. My bet is the recording is out of phase.
   Try it you'll like it. However not all people are capable of decernig correct phase. If your that person consider yourself lucky. One more thing NOT to be concerned with.


charles

[doug s.]

I could not disagree more sorry. some people like myself can call the correct phase when music is played. All recordings are not recorded in phase. A wonerfull option IMO. One that stopped me from buying particular components.
  For me I like it in the source say phono stage or DAC.  Ever notice the music favoring one channel on CDs as opposed to others. Boomy bass as oppossed to focused and tight. Exaggerated sibilance on female voice. My bet is the recording is out of phase.
   Try it you'll like it. However not all people are capable of decernig correct phase. If your that person consider yourself lucky. One more thing NOT to be concerned with.


charles

so, you switch phase for the different phase of each cut on the same recording?  even if my phase switch were on my remote, i don't think i could be bothered.

doug s.

[DustyC]

Try a recording that was done with just a single stereo microphone.
Sheffield Labs and ViTaL records are 2 labels that have examples ("the Name is Makowetz" for Sheffield and "James, James 2" for ViTaL) in their back catalog. A full range single driver speaker helps too (electrostatic). The difference I found during experimenting was slight, but audible.

[rollo]

so, you switch phase for the different phase of each cut on the same recording?  even if my phase switch were on my remote, i don't think i could be bothered.

doug s.

   When you hear the difference you will make the effort. Yes I have found that on some CDs the first track is out of phase and the next is in phase. Meaning the odd numbered tracks are out and the even numbered in phase. On LPs especially I find the bass out of phase to the music. Scott Markwell demoed this to me at his home and at Harry Pearsons and frankly was amazed at the difference in bass performance when he flipped the switch. It is the recording that is the issue, so we need to make corrections.


charles

[Wayner]

Rollo and Doug s. We have 2 different topics going on here and I think both of you have missed the boat a little, perhaps it's the threads fault. We are not talking about +phase and -phase that some folks around here have discussed (flipping both phases of the speakers in and out). What Frank refers to as a phase inverter actuall puts one channel out of phase with the other channel in a single chassis amplifier. This helps the transformer respond better and also helps to cancel distortions. Here is the trick, now when using this configuration, you connect one of your speakers out of phase, so both speakers are "in phase" with each other. The amp's channels are not, nor is the preamps inverter outs.

Perhaps this wiring diagram will help you understand:

 

Wayner 

[doug s.]

wayner, i got it, when turkey first posted it.  but the topic got a bit off-tangent to what i first thought the phase thing was.   

thanks,

doug s.

[Wayner]

Cool! Have a good one.

[modular747]

I could not disagree more sorry. some people like myself can call the correct phase when music is played. All recordings are not recorded in phase

"In phase" with what??  Moving your head 2 inches left or right, back or front from a live stage changes the relative phase of sound coming from instruments in different positions relative to your body. 

I have no doubt some believe they can hear absolute phase change (i.e. reversing the polarity wires to both speakers).  Even so, it is merely a preference.  Unless the original sound was from a point source, there is no objective "correct phase."

Don't confuse this with relative phase difference between speakers (i.e reversing wire polarity with only 1 speaker).  This is profoundly audible to everyone, distorting the imaging and washing out the bass.

[doug s.]

Cool! Have a good one.

hey wayner, your description & diagram will be a great help for those who might not understand.   

doug s.

[doug s.]

"In phase" with what??  Moving your head 2 inches left or right, back or front from a live stage changes the relative phase of sound coming from instruments in different positions relative to your body. 

I have no doubt some believe they can hear absolute phase change (i.e. reversing the polarity wires to both speakers).  Even so, it is merely a preference.  Unless the original sound was from a point source, there is no objective "correct phase."

Don't confuse this with relative phase difference between speakers (i.e reversing wire polarity with only 1 speaker).  This is profoundly audible to everyone, distorting the imaging and washing out the bass.

i'm w/you on this, but i don't wanna argue w/those who believe they can perceive a meaningful difference.  if they can, good for them.

doug s.