What is this cct does?

[lumanauw]

What happened if I turn VR6 CCW or CW? What is the meaning of "Phase" there?

[kubeek]

after a quick simulation in MicroCap it seems to me that the circuit changes phase of the HF input signal in the range of >100kHz, the change is about 60deg.
What is this circuit part of?

[lumanauw]

Hi, Kubeek,

>100khz? I don't understand. It is one part that I don't understand from one schematic of active x-over. The other parts are ordinary balance-unbalance I/O, gain, filter.

What is "audible" effect if this is turned CW/CCW?

[poobah]

Lumanauw,

It's looks like pin 7 on the terminal block is really the input for this circuit...

Hard to tell exactly what this does without seeing the bigger picture.

[destroyer X]

All both signals beeing the same will be canceled if they were the same amplitude....but you have an adjustment to cancelling...so, any signal will be entirelly deleted, unless you adjust the non inverting input and the inverting input with the same sensitivity.

If you cancell all the signals of the same amplitude, you will be cancelling the signals from, for instance, channel left and channel rigth that are the same...the common audio signal that belongs to both channel at the same time.

The special tones, the ones that are not captured, during recording, by the channel left and channel rigth at the same time, with the same amplitude, will not be erased, they will be not supressed, attenuated, or even deleted in the output signal.

Delayed signals can be understood by echoes...if you generate a small burst of a single tone, for example, 1 Kilohertz, and goes to capture this with a microphone..you will have the main signal and the echoes that will be delayed signals with lower voltage that will be captured after by the microphone, will appear delayed in the wave form monitor.... so.... some sound echo may disappear when you advance your inverted input potentiometer.

As an example, if the singer`s voice of some music was recorded equally in the left and rigth channels...when you reproduce this audio signal, and adjust your phase cancelling op amplifier, you may reduce or cut almost all voice present in the music program, as you invert the same signal from the rigth channel...when those signals are put all together again.... the phase opposition of them will make them null....zero!.

In my imagination, this filter separates the non commom sounds from one source....in the filter output you will have sounds that where not recorded in both left and rigth microphones, unless the sounds that had not the same signal amplitude...you will be able to adjust the non common signals, and those are the sounds that produce the stereo effects and that produce the feeling of sound stage...so...in the output you may have a stronger and more detailed stereo effect....some stereo increaser.....or even voice level reducer.... voice canceller..something alike that...very interesting.

The capacity to be strongly sensitive is limited by the circuitry that is controling the non inverting input gain.

Well.....this is what i think...let`s listen more friends.

Phase concerns timing..... delay or advance related some reference signal..this is some easy understooding in practical world.

Yes!..i can be delirating...let`s wait more friends enter to tell us more things.

Eva`s presence here could be interesting, as she is an excelent audio analist even thinking about the King`s invisible pant`s Tale.

regards,

Carlos

[lumanauw]

Hi, Poobah,

I think the input is from R56/58. But I don't know what pin 7 connected to.
What do you think this configuration do?

Hi, Carlos,

I have to read your reply first

R75 is negative feedback. R74+C69=positive feedback?

[ben goh]

Hi

I think I saw this design before.

It is from a professional product called Klark Teknik.

It is a electronic crossover and this is to adjust the phase shift

between fequency bands.

[destroyer X]

The forum is teaching me English... I am reading and learning new words and also the correct way to write them.

Our forum has this utility to me too.

I love this forum!...bad guys never delay too much to get out, some of them kicked by our silence, others feel tired not to have answers...only the kind ones survive here.

It is reality that the big masters lost their patience with a lot of foolishes we use to say here...but....nothing is perfect in this life, and maybe this is what makes life so interesting.

My texts are turning bigger and bigger... as my English knowledge is turning enormous., and this is because of our forum...i am happy that i had learn the hability to write long texts.

Sorry Lumanauw if i had bothered you, but had very good intentions and i think it is our obligation to help others giving them some ideas about what we think...maybe not the correct idea, but for sure will atract the big engineers to help you, correcting your analisis, filling the gaps and helping you not to be exposed to a ridiculous situation for long time.

Also the not so good guys, and this behaviour evaluation is because some of them come together their giant Egoes..not necessarily to help us, but, showing themselves under the spot, they will be actually, informing us about what we want to know....Oh!....big Egoes loves to say that you are not rigth...but if they accept to explain what is rigth, it will be good to us.

regards,

Carlos

[ben goh]

Hi

I will try to dig out the complete schematic and share.

If you need a copy, drop me a mail.

Thanks

[darkfenriz]

Hi David
This is an all-pass phase shifter, it does not amplify nor attenuate any frequency, but changes phase. As far as I remember phase vs. freq plot looks like -arcus tangens function.
A simpliest analysis of this bases on Laplace transform, function in s-domain looks like H(s)=(s+const)/(s-const) , or at least it is not intuitial for me without harder maths.
Such a circuit is often used in active subwoofer electronics, so that one can match phase between subwoofer/woofer range.
If phase in such a crossover region is in mess, than one cannot tell if acoustic wave are going to add or subtract.

regards
Adam