Phase inverted..why?

Generally, the most commonly used tube circuits used to amplify voltage invert phase. That is, the input (voltage swing at tube's grid) and the output (voltage swing at tube's plate) are inverted. This is just the way it works.
Notice at the link below that the sine wave for the output is not only larger because it is amplified but it is moving exactly the opposite of the grid and input voltage sinewaves.
http://www.tpub.com/content/neets/14178/css/14178_37.htm

Typically, you can count the number of such stages and figure out if the amp inverts. Two stages brings it back "in phase" three stages and you are "out of phase." This is not always true as there are some circuits, like cathode follower buffer stages( used to match impedances within the amp) that do not invert phase because the output is not taken from the plate circuit.

Sonically, IMHO, it is not a big deal.

If you are interested read more at the site given above or chapter 1 here:http://files.experimental.ch/Navy/14178.pdf

I think the chapter1 of the above materials is about as good an intro to how tube circuits work as there is on the web.

Cheers
I remain,

Hi Dave, Happy New Year! The usual reason some products present a phase inversion is to eliminate a superfluous stage to restore it back into phase, all part of the KISS philosphy.

I'm somewhat confused and, obviously, not an electrical engineer. However, if the solution to the phase inversion problem is to reverse the speaker cable polarity, why don't the manufacturers just wire the output that way in the amp.

Sorry for the stupid question.

Clueless-Your post shows how 'unclueless' you are.Thank you..
Unsound-Hey bud,Happy New Year to you also!
KISS? is that a secret message or does it stand for something? :~)

David, .....KISS is an acronym for Keep It Simple, Stupid.

KISS = Keep It Simple Stupid...

Would someone please answer Wstritt's question. I have always wanted to know this. Wouldn't reversing the internal wires to the preamp's output jacks put the signal back to correct phase?

said above >>However, if the solution to the phase inversion problem is to reverse the speaker cable polarity, why don't the manufacturers just wire the output that way in the amp.

said above >>Wouldn't reversing the internal wires to the preamp's output jacks put the signal back to correct phase?

My 2c is that there really is no problem to solve because there is no "correct phase" in the general sense. For a single track you can sometimes determine when the mic and speaker are moving in the same direction and some rigs do come with a switch. However, from one cut to the next there is no standard to set your amp's phase to.

Remember that when you talk about phase you always need to ask in relation to what? Unfortunately the recording process is a long and complicated affair. Phase is inverted and otherwise changed many times. The microphone, cables, mixing console, tape machines and signal processors (delay, echo, reverb, equalizers, limiters etc., etc.) might each be wired out of phase with respect to one another. In addition, smaller phase errors (several degrees here and there) may occur within the electronics of any of these components.

Different cuts from one disk will not have a standard phase and even tracks of one tune will not be recorded so that they have an absolute or correct phase.

In addition, the phase of different parts (frequencies) of the signal will change phase to some degree but not 180deg.
This happens anytime reactance is introduced (inductors,transformers, capacitors etc)in the recording and reproduction of the signal.

Also, in some systems if you reverse the polarity of the speaker wires, and hear a difference, you may be listening to more than "correct phase." Check out this article on SETS and reversing speaker wires.http://usuarios.uninet.com.br/~edelima/REASONS.htm

P.s. the comments in my first post are SET and transformers invert phase too and differential amps work either way...

I remain,

If you remain clueless, I must be just plain dumb!

forgive me for being clueless...
but my rudimentary understanding of polarity is that it refers to the +/- charges delivered to the speaker.

As long as both speakers are running the +'s at the same time is there really an issue?

I use a Rogue Magnum 66 currently running to a Rogue m88 and have my +'s on the amp to the +'s on the speakers.

Are you saying that I really should reverse the speaker wires into the amp?

Geoffgarcia,

The Rogue66 inverts phase. So, this is 1 phase inversion.
Does the Rogue 88 invert phase?
If yes, this is the 2nd phase inversion. Hence, no need to cross speaker connections as 2 phase inversions of 180 degree brings you to 360 degrees, which is the same as zero phase inversion.

If the Rogue88 does *not* invert phase, then you have to cross speaker connections.

Hello Geoff,
Yes, like many tube preamps, the 66 is phase inverting. You should reverse the speaker wires on both channels as you state. You should also know that this is a subtle difference and many recordings are phase inverted so you
can't always have it in phase anyway. I hope this helps -- Mark

----- Original Message -----
From: "Geoff Garcia"
To:
Sent: Tuesday, January 13, 2004 11:38 AM
Subject: Rogue m66 question on phase

> Hello!
> I read the forums on audiogon and have noticed a question that popped up about your m66 preamp and phase inversion.

> Currently I run the m66 to a m88 and have my speaker cables running + to + and - to -.
> From what I understand from this thread its saying I should run the speaker cables in a - to +, - to + fashion?
> Is this correct?
> Thanks for any help, Geoff

Now that I have my 66 magnum installed and have had a chance to experiment I hear no difference at all.

its difficult to hear phase problems unless you have an ear for them or test discs

Some years back reviewers were carping about absolute phase and audiophiles began to train themselves to here the difference in polarity. I couldn't hear it and I decided not to try. After all, if I couldn't hear the problem, there wasn't one.
The only phase issue I've been concerned about since is the phase relationship between my speakers and my subs.

Clueless - In the immortal words of John Wayne - "Not hardly". Thanks for the clarification.

Alot of recordings aren't in phase and further some tracks on CD's are in and some are out - I used to switch speaker connections but don't anymore. Most CD front ends have phase reversal switches - but I can't hear any difference. I think it's all HW. That's hogwash...

its not hogwash at all...
go buy a cd with a polarity test on it and then swap around your cables...
if you can't hear the difference you have some major hearing problems

No hearing problems here - got a little tendonitus in the left elbow though.

Pops, did you develope the tendonitus loading disks and Lps? The fairly rare and often undiagnosed "music-lover's elbow." Work on loading with the right hand.

I'm in awe!!

Sincerely
I remain

That's what the doc said - pretty impressive huh?