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by mediatechnology
Wed Aug 04, 2021 2:25 pm
Forum: Pro Audio Design
Topic: The Studer "90° Filter" Stereo to Mono Summer/Recorrelator
Replies: 20
Views: 3976

90 Degree Filter Sound File Comparison

I ran a comparison of the Quadrature 90 Degree Filter versus Stereo and conventional L+R Mono. The waveforms tell a large part of the story. The first cut is conventional stereo, the second is L+R and the third the "quadrature" sum. (Right-click to enlarge) https://proaudiodesignforum.com/images/jp...
by mediatechnology
Wed Aug 04, 2021 12:03 pm
Forum: Document
Topic: Digikey leadtime trends
Replies: 3
Views: 15

Re: Digikey leadtime trends

The table for semiconductors is particularly discouraging.

There was a polysilicon plant that recently burned which makes it go from bad to worse.
by mediatechnology
Tue Aug 03, 2021 2:51 pm
Forum: Build
Topic: Return of the Linear/Magnetic Wall Wart for the US Market
Replies: 0
Views: 15

Return of the Linear/Magnetic Wall Wart for the US Market

Linear transformer-based wallwarts literally disappeared form the market a number of years ago due to EU efficiency regulations. Triad magnetics has re-introduced "wall mount" for industrial and commercial applications for the 60 Hz US market. AC Output Triad Magnetics Wall Mount AC Adapters: https...
by mediatechnology
Tue Aug 03, 2021 5:51 am
Forum: The Peabody Lounge
Topic: The Corona Virus Hoax of 2020
Replies: 422
Views: 170867

FDA document admits “covid” PCR test was developed without isolated covid samples for test calibration

FDA document admits “covid” PCR test was developed without isolated covid samples for test calibration, effectively admitting it’s testing something else A document just released by the U.S. Food and Drug Administration (FDA) openly admits that the infamous PCR test for the Wuhan coronavirus (Covid...
by mediatechnology
Tue Aug 03, 2021 5:38 am
Forum: Pro Audio Design
Topic: The Studer "90° Filter" Stereo to Mono Summer/Recorrelator
Replies: 20
Views: 3976

Re: The Studer "90° Filter" Stereo to Mono Summer/Recorrelator

The summed frequency response is much better using the Weaver alignments. The blue trace is the in-polarity response; the green trace is out-of-polarity response. https://proaudiodesignforum.com/images/jpg/Recorrelator_90_Degree_Filter_Summed_Freq_Response_Weaver_Alignment_Blue_In-Polarity_Green_Ou...
by mediatechnology
Tue Aug 03, 2021 5:18 am
Forum: Pro Audio Design
Topic: Texar Prism clone prototype
Replies: 17
Views: 29084

Re: Texar Prism clone prototype

Thanks for moving to through hole. I'm glad you could find inventory in TH. People are always saying "Why don't you use SMT?" and I counter with "Would you be willing to support the builders who can barely solder through hole to help them clean up their SMT mess?" It's easy for people to say stuff w...
by mediatechnology
Mon Aug 02, 2021 3:24 pm
Forum: Pro Audio Design
Topic: The Studer "90° Filter" Stereo to Mono Summer/Recorrelator
Replies: 20
Views: 3976

Re: The Studer "90° Filter" Stereo to Mono Summer/Recorrelator

This is the actual Studer 90 degree filter alignement.

It looks like Wayne's accidental alignment is better than the Studer's.
Clearly the Weaver is optimum.

Image
Corrected Studer 90 Degree Filter Phase Response
by mediatechnology
Mon Aug 02, 2021 2:58 pm
Forum: Pro Audio Design
Topic: The Studer "90° Filter" Stereo to Mono Summer/Recorrelator
Replies: 20
Views: 3976

Re: The Studer "90° Filter" Stereo to Mono Summer/Recorrelator

The Studer 90 degree filter's phase response using the improved "Weaver" alignment. https://proaudiodesignforum.com/images/jpg/Studer_90_Degree_Filter_Phase_Response_Improved_Weaver_Alignment.jpg Studer 90 Degree Filter Phase Response Improved Weaver Alignment The Weaver alignment looks ideal. I ne...
by mediatechnology
Mon Aug 02, 2021 12:29 pm
Forum: Pro Audio Design
Topic: The Studer "90° Filter" Stereo to Mono Summer/Recorrelator
Replies: 20
Views: 3976

Re: The Studer "90° Filter" Stereo to Mono Summer/Recorrelator

Here's what the Studer 90 degree filter's phase response looks like using E96 roundings to Studer's original values. Edit: This turns out to be "Wayne's Accidental Alignment" because I hadn't updated the protoboard to the exact values. https://proaudiodesignforum.com/images/jpg/Studer_90_Degree_Filt...
by mediatechnology
Mon Aug 02, 2021 11:48 am
Forum: Pro Audio Design
Topic: The Studer "90° Filter" Stereo to Mono Summer/Recorrelator
Replies: 20
Views: 3976

Re: The Studer "90° Filter" Stereo to Mono Summer/Recorrelator

Frank - Thanks for the values!
I'll try to run a phase plot on the original and modified values this afternoon.