500 series API 312 with 180° phase adjust

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Hi Peter,



  dunno how I missed this . ..


    I am REALLy interesticated in a phase rotator, esp if it is all discrete n all . . . I agree it would be a wonderful thing at line level, since I think we all have a loada pres . . . I am often having to sort out other peoples recording messes, with no attention to phase.



    Bloomin wunderbar , , ,


  ANdyP
 
okgb said:
Don't hit me peter , please .....................

If you mean , being able to vary the phase [shift ] from 0-180 , THAT i could use
for my multi mic'ing & d.i.  inputs

I am cursed with people beating me off the start  ::)

That being said, however, I am glad to have found what I was looking for before starting a new post.  It has enormous potential.

A user selectable phase adjust is precisely what I want to include in a project, once I have everything conceptualised.  180 degrees is slightly extreme in my circumstance.

Would this, and forgive my ignorance - I am literally jumping into the deep-end - be acquired using a variable rectifier?  Think I read somewhere that Capacitors can phase the release of a/the signal - Could this also accomplish this?

This is all very new to me - bit like trying to drink upside down.

All the best.  ;D
 
Right, it seems it was almost infront of us the whole 'time'  ;)

If any one can verify this - please do

'resistive-capacitive (RC) citcuit... a resistor and capacitor in parallel will delay the phase of an AC circuit. As long as the components are capable of handling the voltages and currents applied in the circuit a RC circuit can change the timing from zero phase delay to 180° phase delay and beyond.

By varying the resistance you vary the amount of time it takes to charge the capacitor thus delaying the phasing of the circuit'.


Esentially it's no different to the attack Pot on a compressor.  Nice to know I wasn't too far off hehe.

Needless to say, there is an equation that will allow us to compute this phase.  Can anyone add to this? 

If any one can add to this, I'd, and I dare say others, would be most appreciative.

All the best.  ;D
 
I've not had much (more like any) DIY time lately but I'd be interested in this if someone gets it going.

Here's a link to an all pass filter that should be a very good starting point. 
All that might be necessary is to figure out how to implement the variable part of the circuit.


http://www.w3am.com/8poleapf.html
In fact there is a board already built being sold on ebay.
search "Phase Rotator Module"
8poleapf.gif
 
Me too Greg, I want one. 
I'd do it, but I think you need better design skills than I've got.
not even close.
I was doing some reading today...
If you read PRR's post in one of the other phase adjust threads  ( which jibes with the siegfried linkwitz article on phase adjustment) it would seem that the high and low frequencies sweep around as the adjustment is made... it would need a very particular custom taper pot or some kind of algorithmic circuitry to make the high and low sweep in a nice musical way.
Pretty complicated.
 
Interested in a pair. I've got more pres than I need so I don't care too much for having it as a pre also but it couldn't hurt if all the components are pretty much the same. Into it being 500.
 
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