[Wayner]

Thanks doug.

Here is what the Phase Inverter Bridge can do for you if you have 2 identical amplifiers:

 

Wayner 

[turkey]

   When you hear the difference you will make the effort. Yes I have found that on some

Given that there is no standard for absolute phase in the recording process, and since so many recordings are multi-channel and the phase varies even within the recording, I don't see it's a real issue.

Then there is the fact that research has shown that it's almost never audible.

Add in most speakers, which don't maintain phase throughout their bandwidth. Even ones without crossovers don't have perfectly flat phase response from the lowest to highest frequencies. (Since we don't yet have materials allowing perfect pistonic motion.)

[turkey]

"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."

I agree.

[rollo]

  Hey Wayner I was confused a bit as well with the subject. Anyway good thinking again from AVA.


charles

[Birdbrain]

So, can you get a T8+ with phono, tape buffer and phase inverter options, for $1896?

[rlee8394]

What we are talking about is providing simultaneous non-inverted and inverted signals to dive a common ground stereo amp in a bridged configuration. This would yield roughly 2-3 times the output power, provide greater separation, and eliminate common mode noise. You would need one stereo amp per channel.

We are not talking about providing a selectable phase switch to flip the signal between in phase or out of phase through the playback chain.

[Wayner]

Lee gets it.


 

or

 
Wayner

[jtwrace]

If you hook it up that way it appears that the phase will off.   

[Wayner]

No, it's not. Look at the speaker phasing in particular. I'm gathering that people for the most part don't understand what the phase inverter does. It has almost nothing to do with "acoustical" phasing, rather, electrical. The preamp has the ability to put one channel diametrically out of phase with the other channel. This is done to make the power supply of the amplifier more efficient. If you have 2 amplifiers, you can double your RMS power output with tube amps, tipple the RMS power amp with SS amps. If you have just one amplifier, it will make the amplifier's transformer/power supply much happier, giving you much more headroom. The speakers are wired out of phase, to put them back into phase, electrically and thus acoustically.

W

[martyo]

Thanks Wayne! 

[trebejo]

No, it's not. Look at the speaker phasing in particular. I'm gathering that people for the most part don't understand what the phase inverter does. It has almost nothing to do with "acoustical" phasing, rather, electrical. The preamp has the ability to put one channel diametrically out of phase with the other channel. This is done to make the power supply of the amplifier more efficient. If you have 2 amplifiers, you can double your RMS power output with tube amps, tipple the RMS power amp with SS amps. If you have just one amplifier, it will make the amplifier's transformer/power supply much happier, giving you much more headroom. The speakers are wired out of phase, to put them back into phase, electrically and thus acoustically.

W

On the single-amp usage of this option, I got a question about this wrt the Ultravalve. The last time I tried to understand one of the circuit diagrams of the ST-70 as described in Frank's newsletter, it looked like this phase splitting was already being done in this amp? In general, it seems like a clever trick to put into an input stage if you can do it.

I assume it is useful for one of Frank's solid state and hybrid amps? That's my summer setup.