Search found 17 matches

by fredbloggstwo
Mon Feb 13, 2023 8:06 am
Forum: Pro Audio Design
Topic: The Studer "90°" Dome Filter Stereo to Mono Quadrature Summer
Replies: 48
Views: 108485

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

Hi again,

the version I was thinking of was the 'Recorealator' version that you posted on Mon Aug 02, 2021 at 2:58.

Cheers

Mike
by fredbloggstwo
Sun Feb 12, 2023 8:53 am
Forum: Pro Audio Design
Topic: The Studer "90°" Dome Filter Stereo to Mono Quadrature Summer
Replies: 48
Views: 108485

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

Hi Wayne,

did you ever make up a PCB for this filter?

Kind regards

Mike
by fredbloggstwo
Wed Nov 10, 2021 8:18 am
Forum: Pro Audio Design
Topic: Universal Tape EQ converter
Replies: 9
Views: 8286

Re: Universal Tape EQ converter

Hi all, just to round this subject off, I took the useful tables from Jay McNight's paper and put them and their counterparts into a spreadsheet and thought I would share it. I also converted the VU dB levels to voltage in case you prefer them that way. If anyone finds any glaring mistake, please le...
by fredbloggstwo
Fri Oct 29, 2021 2:32 pm
Forum: Pro Audio Design
Topic: Universal Tape EQ converter
Replies: 9
Views: 8286

Re: Universal Tape EQ converter

Further research (lurcing) brought the enclosed PDF to light from MRL which makes things a bit easier. 02-209 MRL Choosing and using tapes.pdf Page 8 is a real nugget of information. As the author (Jay McNight) points out in the text, you can reverse the columns of "Recorded Frequency" and...
by fredbloggstwo
Fri Oct 29, 2021 8:16 am
Forum: Pro Audio Design
Topic: Universal Tape EQ converter
Replies: 9
Views: 8286

Re: Universal Tape EQ converter

Hi Wayne,

Thanks for the reply.

I thought a bit about a digital domain answer but wanted to stick in the analogue domain if possible. Judging by the rush of replies, it looks like I will just have to switch replay amps when necessary. :)

Cheers.

Mike
by fredbloggstwo
Thu Oct 28, 2021 11:34 am
Forum: Pro Audio Design
Topic: Universal Tape EQ converter
Replies: 9
Views: 8286

Universal Tape EQ converter

Hi All, I have accumulated a few NAB tapes over the year and playing them back is usually a bit of a pain - I use a Studer A80RC machine and involves swopping out the Reproduce channel cards (I could just swop the EQ plug ins but that would then involve setting up the cards again) and I was wonderin...
by fredbloggstwo
Sat Jul 31, 2021 10:15 am
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 162
Views: 326895

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
by fredbloggstwo
Sun Jul 25, 2021 11:28 am
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 162
Views: 326895

Re: Super Low Distortion Ultra Pure Audio Oscillators Revisited

Hi again Wayne, I tried the OPA 1656 chip in the notch filter and it works fine. Here's some photos of the attenuator I built based on 'O' or 'Box' pads. I recommend this type of pad as it is 'ground free' and so does not have any grounding funnies. My fancy 'scope which also does Bode plots, shows ...
by fredbloggstwo
Sat Jul 17, 2021 3:54 pm
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 162
Views: 326895

Re: Super Low Distortion Ultra Pure Audio Oscillators Revisited

Hi again Wayne, I built the 1-2-2-5/10-20-20-50 ratio attenuator according to the spreadsheet I posted and it works well with the stated attenuation spot on. The Schadow switches work well. I also added a 600R termination switch so as to terminate the attenuator chain - the stage after the attenuato...
by fredbloggstwo
Tue Jun 29, 2021 8:44 am
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 162
Views: 326895

Re: Super Low Distortion Ultra Pure Audio Oscillators Revisited

Hi Wayne, Thanks for the kind words. I use a silent switcher to power an existing sound card output interface, but when I bought it it came from the US (instead of Europe where Jan Didden is based) and cost me a fortune in import duties and 'commission. So I have started using a Chinese copy ( https...