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by mediatechnology
Tue Aug 03, 2021 5:38 am
Forum: Pro Audio Design
Topic: The Studer "90° Filter" Stereo to Mono Summer/Recorrelator
Replies: 19
Views: 3951

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: 16
Views: 29038

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: 19
Views: 3951

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: 19
Views: 3951

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: 19
Views: 3951

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: 19
Views: 3951

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.
by mediatechnology
Sat Jul 31, 2021 9:22 pm
Forum: Pro Audio Design
Topic: The Studer "90° Filter" Stereo to Mono Summer/Recorrelator
Replies: 19
Views: 3951

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

Thanks for doing the calculations. What would be the Weaver values scaled similarly to my implementation? It looks like the GroupDIY simulation of the amplitude response shows the same anomaly around 5 kHz as your Studer calculations. I need to do a phase response plot. I've never used that tool in ...
by mediatechnology
Sat Jul 31, 2021 9:00 pm
Forum: The Peabody Lounge
Topic: The Corona Virus Hoax of 2020
Replies: 421
Views: 170761

CDC releases study showing 3/4 Delta cases are among the vaccinated

CDC releases study showing 3/4 Delta cases are among the vaccinated, says masks are the answer The CDC has released a study backing up its decision to recommend indoor masking for both vaccinated and unvaccinated Americans. The study examined one outbreak and found three-quarters of people testing ...
by mediatechnology
Sat Jul 31, 2021 1:44 pm
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 156
Views: 180162

Re: Super Low Distortion Ultra Pure Audio Oscillators Revisited

I just checked Atto's balanced attenuator error by reading directly in DC mV and then converting to dB. This time I had the build-out resistors included. The load was 597.5Ω. +10 +0.054 dB 0 (calibration point) -10 +0.03 dB -20 +0.052 dB -30 +0.084 dB -40 +0.12 dB -50 +0.157 dB -60 +0.257 dB -70 +0....
by mediatechnology
Sat Jul 31, 2021 10:40 am
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 156
Views: 180162

Re: Super Low Distortion Ultra Pure Audio Oscillators Revisited

Nice one Wayne, your attenuator board looks a lot better than mine :) I'll add the osc mods to my board when I am next down the workshop. I also added a switch to the notch filter input to put the osc in circuit. Twisted pair seem to work ok. Cheers Mike Thanks Fred. I'm intending to do the very sa...