Search found 4744 matches

by mediatechnology
Mon Jul 05, 2021 5:51 am
Forum: The Peabody Lounge
Topic: Entropy
Replies: 1299
Views: 613253

Re: Entropy

Makes me very glad I don't own any rental property.
by mediatechnology
Wed Jun 30, 2021 11:27 am
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 149
Views: 179653

Re: Super Low Distortion Ultra Pure Audio Oscillators Revisited

Mike - I had a chance to open the attenuator spreadsheet - it's very well done. I just remembered that the Heathkit attenuator is single-ended. The 4PDT F4 switch seems like the most practical if the contact distortion remains low over time. Would you use Gold on yours? I've had very good luck with ...
by mediatechnology
Wed Jun 30, 2021 7:54 am
Forum: The Peabody Lounge
Topic: The Corona Virus Hoax of 2020
Replies: 417
Views: 170019

"Panic Porn Dressed Up As Science" - Exposing The Truth About The Delta Variant

"Panic Porn Dressed Up As Science" - Exposing The Truth About The Delta Variant https://www.zerohedge.com/covid-19/panic-porn-dressed-science-exposing-truth-about-delta-variant But is the Delta variant really "far more contagious" than earlier iterations of SARS-CoV-2? In a recent piece published b...
by mediatechnology
Tue Jun 29, 2021 10:41 am
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 221
Views: 253906

Re: Phono Transfer System Construction Information

The preamp schematic would give us a clue about the head impedance. The active preamp would be the best one to look at. I would think either the MM or MC preamp could be adapted.
by mediatechnology
Tue Jun 29, 2021 9:58 am
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 221
Views: 253906

Re: Phono Transfer System Construction Information

Paul -

Send me a scan of the A80VU preamp and I'll have a look.

Wayne
by mediatechnology
Tue Jun 29, 2021 5:18 am
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 149
Views: 179653

Re: Super Low Distortion Ultra Pure Audio Oscillators Revisited

Nice work Mike! Would the USB Power supply you are referring to be a Silent Switcher? Your photo made me go to eBay and look for a Leader LAT-45. I remember that when I modified my IG-18 in the early 1980s with the Morrey Super Oscillator board I bought an extra attenuator switch and removed the old...
by mediatechnology
Sat Jun 26, 2021 10:27 am
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 149
Views: 179653

Re: Super Low Distortion Ultra Pure Audio Oscillators Revisited

I think the Output Level range at the low end of adjustment needs to be limited by increasing R30. It's currently about -10 dBu minimum with a range of -10 dBu to +26 dBu on the balanced output. There are two reasons for this. 1) The oscillator has the best THD in the range of +10 to +20 dBu output....
by mediatechnology
Fri Jun 25, 2021 9:48 am
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 149
Views: 179653

ULDO-Nacho FFTs and THD

I built a second ULDO-Nacho board and made some 1 M point 50 sample average FFTs. The Y-axis in the following FFTs have offsets to reflect the post notch filter gain (+40 dB) and the "carrier" (output level). The result is dBc and does not reflect the insertion loss of the notch filter. The Left ch...
by mediatechnology
Thu Jun 24, 2021 5:43 pm
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 149
Views: 179653

Re: Super Low Distortion Ultra Pure Audio Oscillators Revisited

Updated ULDO-Nacho Assembly and Test Instructions with Schematics: https://proaudiodesignforum.com/images/pdf/Ultra_Low_Distortion_Oscillator_Assembly_Instructions_ULDO-Nacho_18_Assembly_And_Test_070821_1.pdf Mouser Project Manager BOM for ULDO-Nacho: https://www.mouser.com/ProjectManager/ProjectDe...
by mediatechnology
Wed Jun 23, 2021 1:09 pm
Forum: Pro Audio Design
Topic: Super Low Distortion Ultra Pure Audio Oscillators Revisited
Replies: 149
Views: 179653

Re: Super Low Distortion Ultra Pure Audio Oscillators Revisited

Using a 5532 I just checked the output offset on the first PC board and it's about -1.8V with the notch filter unbalanced and about -130 mV with the jumpers set to balanced. That offset is primarily due to Ib*100KΩ*Gain. I made Rbias large to allow a lowish value polypropylene film cap and let the o...