Martin Griffith

Studer 1 194 533. 90 degree shifter. LTspice file
« on: June 03, 2016, 01:11:12 PM »
Just trying out dropbox.
A  ecent topic about 90 phase shift. so did a LTspice asc file

https://www.dropbox.com/s/k3dzlzu9ixsuola/Studer1_194_533.asc?dl=0


abbey road d enfer

Re: Studer 1 194 533. 90 degree shifter. LTspice file
« Reply #1 on: June 03, 2016, 05:44:41 PM »
Just trying out dropbox.
A  ecent topic about 90 phase shift. so did a LTspice asc file

https://www.dropbox.com/s/k3dzlzu9ixsuola/Studer1_194_533.asc?dl=0
Is it the actual values in the Studer unit? because the phase shift is not very consistent; I'm used to better performance from the Studer engineers. I had in my old LTspice files an experiment and I had very consistent 90° shift over a 6 octave range with only two stages. With 4 stages I would expect perfect linearity across the whole audio spectrum.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

Martin Griffith

Re: Studer 1 194 533. 90 degree shifter. LTspice file
« Reply #2 on: June 04, 2016, 03:07:29 AM »
Yep, original values, from the Studer datasheet, I've put the Studer doc on there as well. I left out the 6k8 summing resisitors on the output in the LTspice file.  the studer circuit has 2 signal paths with different filters which are summed together. I think this is the pdf link https://www.dropbox.com/s/qzdxh0x4zslakhv/1.914.533.pdf?dl=0 (Still trying to get the hang of dropbox)
« Last Edit: June 04, 2016, 04:54:03 AM by Martin Griffith »

abbey road d enfer

Re: Studer 1 194 533. 90 degree shifter. LTspice file
« Reply #3 on: June 04, 2016, 12:19:47 PM »
Yep, original values, from the Studer datasheet,
That's weird; as I wrote before, I think it is possible to improve significantly the accuracy and variance of phase-shift; I just wonder why the Studer designers have chosen to settle for 80° shift maximum. I know it doesn't make much practical difference, though.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

audiomixer

Re: Studer 1 194 533. 90 degree shifter. LTspice file
« Reply #4 on: June 04, 2016, 03:51:20 PM »
maybe that's the difference between perfect in theory to perfect in practice...

- Michael

Re: Studer 1 194 533. 90 degree shifter. LTspice file
« Reply #5 on: June 04, 2016, 11:23:48 PM »
Also keep in mind that this kind of tool is originally used as mono sum for AM radio, one octave is enough  :)
I don't have LTspice to look at file and see what you see,
but if both side have same inconsistency in phase shift at same place, the sum will be ok ? or maybe I'm wrong.
What this do exactly? +45 at one side and -45 at the other ?

Best
Zam

Martin Griffith

Re: Studer 1 194 533. 90 degree shifter. LTspice file
« Reply #6 on: June 05, 2016, 02:31:30 AM »
Couple of pics with the output mixing.  With  inputs in and out of phase. Phase looks linear but the amplitude is a bit weird.
https://www.dropbox.com/s/wsm439oqtrykxnl/stude_0ut_rphase.jpg?dl=0
https://www.dropbox.com/s/f93ba0gadj1d0yv/studer_in_phase.jpg?dl=0

Re: Studer 1 194 533. 90 degree shifter. LTspice file
« Reply #7 on: June 05, 2016, 07:52:00 AM »
Hi

Thanks to share picture ! now I see

Curve show a pb at second filter, and I check your schemo, capacitor of first channel second filter  should be 22n not 10n !!!
(C2 at your drawing, C5 at studer drawing)
I don't check all other component value, but maybe a double check at your side will be a good thing to do :)

Let us see how it work with corrected value !

Best
Zam

Martin Griffith