Ricardus

I'm just wondering why this needs a phase reverse switch when most preamps already have that?
Audio mastering for hire..


Whoops

Yes, you can generally hear the difference of polarity. 

Generally?
No you can't. Generally you can't hear any difference at all when you are soloing 1 track and flip it's Polarity.

Lennie's problem is not related at all to the people that discuss they can hear absolute polarity, he complained of low end loss.
The problem is somewhere in the circuit don't chase ghosts

Lennie

Yes, you can generally hear the difference of polarity.  Not always, but many times.  Plenty of literature out there concerning that.    Many sources do not make symmetrical waveforms, and it's audible.

Agree with Ian.

I agree with you. Does reversing the two wires at pins 2 and 3 when needed work to make the mic in phase with another that is out of phase with it?

EmRR

I agree with you. Does reversing the two wires at pins 2 and 3 when needed work to make the mic in phase with another that is out of phase with it?

Yes.  One polarity to the other. 
Best,

Doug Williams
Electromagnetic Radiation Recorders

"I think this can be better. Some kind of control that's intuitive, not complicated like a single knob" - Crusty

"Back when everything sounde

Whoops

I agree with you. Does reversing the two wires at pins 2 and 3 when needed work to make the mic in phase with another that is out of phase with it?

Like EmRR said, Polarity, not phase.

Differences in Phase development of two signals are timing differences, Delay diferencies.

What you are talking is Reversing Polarity

Whoops

Record exactly the same signal though the circuit 2 times.
First time with the switch in normal position into first track
Second time flip the switch to the Polarity reverse position and record that same signal to the second track.

Send us both wave files do we can have a listen

Lennie

Re: Low output ribbon/ dynamic microphone phantom-powered circuit
« Reply #26 on: January 19, 2020, 03:58:56 PM »
As I already told you in the previous post what you mean is "Polarity Reverse" , "reverse-phased" is something that doesn't exist

With a loudspeaker, reversing the polarity as compared to another speaker operating alongside with it reverses the phase. Is this not the same as a microphone?

[Accidental reversal of speaker wires can happen when the wires are not properly labeled for polarity. This action is known as making the speaker "out of phase," and results in audio oddities. ... Reversing speaker wire polarity is a common audio error.]

Ricardus

I can't believe people are getting so uptight about the polarity/phase thing. I call it phase and always will because audio is an AC signal, it does not have polarity. DC has polarity.

But I have checked the phase switches of every preamp I have ever built, and I can definitely hear slight differences in signal (mild low end differences), and I know those preamps are wired correctly.

It seems to be mostly noticeable when you're real close to say a LD condenser, and the mic is putting out lots of proximity effect low end.
Audio mastering for hire..

Whoops

I can't believe people are getting so uptight about the polarity/phase thing. I call it phase and always will because audio is an AC signal, it does not have polarity. DC has polarity.

I hope you study a bit and get to understand and learn why what you wrote is completely ridiculous

You are a new member around, and you can take your time here to learn something, specially from members that are much more knowledgeable than you.

Stop and Learn



Lennie

Yes, you can generally hear the difference of polarity.  Not always, but many times.  Plenty of literature out there concerning that.    Many sources do not make symmetrical waveforms, and it's audible.

Agree with Ian.

Hi again. Here's something I just found on another blog in which the words 'phase' and 'polarity' are used interchangeably:


well, it is...and it isn't. I've had several discussions on here with some people, and without getting too deep into the physics of it all ('cause I hardly understand it myself), the switch does do a phase shift as well. It's just not in the same "time" domain that we're so used to when talking about two distant mics. But in the rest of the physics world it does. I can probably hunt down the link of the convo we had awhile back if you want.

but drummerboy for your questions, Harvey's right. It takes the parts of the wave form that goes up and makes them go down instead. And vice versa for the part of the wave that goes downwards. It can help in situations where gear may have been improperly wired (although very few people may actually realize this just by hearing it), but more importantly it may help correct where you have phase problems with your signal. This can happen anytime you use two microphones on a source. For example, using a top and bottom microphone on a snare. Using the phase/polarity button helps you listen to a quick fix of how the two sounds appear when they are played back together. Sometimes it helps, sometimes it doesn't.


Whoops

Re: Low output ribbon/ dynamic microphone phantom-powered circuit
« Reply #30 on: January 19, 2020, 08:02:04 PM »
With a loudspeaker, reversing the polarity as compared to another speaker operating alongside with it reverses the phase. Is this not the same as a microphone?

No it reverses the Polarity of one speaker compared to the other. 2 Sources of the same signal with different Polarity,  You will notice some frequencies cancel out.

It's not the same  as if you have a  Microphone soloed and you reverse the Polarity, 1 Source of the same signal, both speakers will play the signal at the same Polarity.

Whoops

the switch does do a phase shift as well.

No it doesn't , time domain remains the same. What the switch does is invert the Polarity of that signal.

('cause I hardly understand it myself)

I know, so there's always an opportunity to understand it,
this is a forum were members are always learning with each other.

Whoops

Back to your question, so we can help you out and listen to what's going on to understand what might be wrong with the circuit, try to do what I suggested

Record exactly the same signal though the circuit 2 times.
First time with the switch in normal position into first track
Second time flip the switch to the Polarity reverse position and record that same signal to the second track.

Send us both wave files do we can have a listen

 I believe Polarity is correct here and is what I've always used, but a surprising number of manufacturers do use the term 'phase'.
 
« Last Edit: January 25, 2020, 01:41:20 PM by Winston O'Boogie »

As for the circuit posted in reply no. 3,  Using 2SK170 transistors for the cascoding devices isn't the best.  They will be biased up with very little GS voltage, too little to allow proper operation of the lower 2SK170 gain transistors.
Better to look for something that has a couple of volts+ gate-source voltage at the current used.   These cascodes don't need to be anything esoteric, the noise and gain will be determined by the lower K170 devices.

However, as discussed in another thread, about the only benefit of cascodes here is to limit the Drain voltage of the lower transistors which can become noisy with over 15V across them.     I think there are better ways to skin this cat if trying to keep the parts count down. 


Whoops

I believe Polarity is correct here and is what I've always used, but a surprising number of manufacturers do use the term 'phase'.
 

Yes, a lot of manufacturers use the word wrongly and I think thats the main problem.
Don't know when it started, but just checked the original Neve 1073 and it says "PHASE" in the Polarity Reverse switch, so it seems  some manufacturers are doing it wrongly for a long time, I think the 1073 module is from around 1970.
Or maybe as Neve is so well known a lot of other companies copied Neve, like guitar amp builders copied Leo Fender's  "Standby" switch.

I teach for some years now, and I find that there's a lot of audio engineering students that have difficulties in understanding even basic phase concepts, because they got it wrong from the start when they were lead to confused a Polarity Reverse button with a Phase difference.
It's not a big deal for someone more experienced that already understands both concepts, you just have to know some people use the wrong term for a Polarity Reverse, but It can be a backbone for people that study audio.

Ricardus

I hope you study a bit and get to understand and learn why what you wrote is completely ridiculous

You are a new member around, and you can take your time here to learn something, specially from members that are much more knowledgeable than you.

Stop and Learn

Yeah, I'll get right on that.
Audio mastering for hire..


I teach for some years now, and I find that there's a lot of audio engineering students that have difficulties in understanding even basic phase concepts, because they got it wrong from the start when they were lead to confused a Polarity Reverse button with a Phase difference.

It's only proper to point stuff like this out, both here and in your classroom.  Folks can choose to take it onboard, or not.

 :)

BTW, I don't want to piss on anyone's parade, but one of our esteemed moderators Abbey has a  PCB he's just prototyped for this type of circuit.  I don't have the absolute details of what he did but it's probably a better use of those J-Fet parts and also has the benefit of emitter followers on the output.  It's mentioned in the Brewery and the Drawing Board for anyone interested and I'd, at least, check it out.

fazer

I started in the 70s on a neve 8036.   Full of 1081s and 1064s.  Like whoops says they have phase switches that do a 180 degree polarity flip from a transformer output.   I’ve called them phase and got use to the term from days of old.   I still say phase but the studio police will bust you for that especially when they are teacher with students.   Also buss for bus is a slip up that forces you to go to studio jail do not pass go.   It’s funny but can turn into a condescending argument for veteran engineers.   That said I push the phase button on a Neve 1081 to fix the polarity of a top and bottom snare mic on one of the pream modules.    Now that I’ve said that I guess I’ll never work in this business again. ;D.   Some body stop me!  LOL

Now that I’ve said that I guess I’ll never work in this business again. ;D.   Some body stop me!  LOL

Haha  :D  You'd get a free hall pass if it were up to me. 
As would everyone else. 
 
« Last Edit: January 25, 2020, 01:41:57 PM by Winston O'Boogie »


 

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