Search found 5449 matches
- Wed Oct 14, 2009 1:58 pm
- Forum: Document
- Topic: SSL Phase Meter Schematic
- Replies: 16
- Views: 32018
Re: SSL Phase Meter Schematic
John - Unless they have a 'scope or are working on a DAW I don't know how they would have a visual indication of absolute polarity in the studio.
- Wed Oct 14, 2009 10:56 am
- Forum: Document
- Topic: SSL Phase Meter Schematic
- Replies: 16
- Views: 32018
Re: SSL Phase Meter Schematic
I did it with log amps and ratios. I don't think it would be too hard in DSP. At some point in the chain you have to define the electrical polarity from the correct acoustic polarity using a measurement mic to define "right-side up" as pressure. If the speaker drive is "waveform posit...
- Wed Oct 14, 2009 10:12 am
- Forum: The Peabody Lounge
- Topic: Are These Two Soundfiles the Same?
- Replies: 1
- Views: 5522
Are These Two Soundfiles the Same?
Here's the first one: http://www.proaudiodesignforum.com/Content/Renee_Olstead-Someone_To_Watch_Over_Me_Cut_1.mp3 Here's the second: http://www.proaudiodesignforum.com/Content/Renee_Olstead-Someone_To_Watch_Over_Me_Cut_2.mp3 Do you hear any differences? No peeking. Resist the temptation to open them...
- Wed Oct 14, 2009 10:01 am
- Forum: Document
- Topic: SSL Phase Meter Schematic
- Replies: 16
- Views: 32018
Re: SSL Phase Meter Schematic
I'm still thinking about when I would want a correlation meter. The scenarios are few. In broadcast about the most obvious application is in machine room/content ingest applications where you occasionally get stereo content delivered with the polarity flipped on one channel. I think it makes sense i...
- Wed Oct 14, 2009 9:39 am
- Forum: Pro Audio Design
- Topic: The 48V Phantom Menace Returns
- Replies: 11
- Views: 24528
Re: The 48V Phantom Menace Returns
Thanks John. The observation about transient interfering with PS rail may explain one difference between my (low) failure experience in mixers and your bench.. I suspect the consoles may have more rail capacitance to soak up the current. (Also I typically used 22 uF). I agree. And there's a lot of o...
- Wed Oct 14, 2009 5:11 am
- Forum: Pro Audio Design
- Topic: The 48V Phantom Menace Returns
- Replies: 11
- Views: 24528
The 48V Phantom Menace Returns
Here's a paper Ros Bortoni and I recently wrote about the phantom menace. Ros has just presented it at AES 127. http://www.thatcorp.com/datashts/AES127-000183.pdf We managed to discover a differential fault mode that's particularly destructive. Previously, the diode bridges to the supply rails have ...
- Wed Oct 14, 2009 4:32 am
- Forum: Pro Audio Design
- Topic: Using the THAT1646 As A Transistor Pre-Driver/Headphone Amp
- Replies: 80
- Views: 350246
Re: Using the THAT1646 As A Transistor Pre-Driver/Headphone Amp
OK, glad that worked out. For RFI filtering you might consider a series R and capacitive shunt ahead of the pot at the RCA jack. With the inverting input of the op amp unaccessible its difficult (impossible?) to put it in the feedback loop.
- Tue Oct 13, 2009 1:58 pm
- Forum: Pro Audio Design
- Topic: VCA theory question
- Replies: 36
- Views: 54192
Re: VCA theory question
Why not use the 4.98V directly - why scale it down? Like John I'm not sure I understand the question either. But if you want to apply 4.98V directly to Ec+ or Ec- it will cause problems. Ec is limited to less than one Vbe or the junctions in the gain cell will become reversed biased. Take a look at...
- Tue Oct 13, 2009 1:27 pm
- Forum: Pro Audio Design
- Topic: Using the THAT1646 As A Transistor Pre-Driver/Headphone Amp
- Replies: 80
- Views: 350246
Re: Using the THAT1646 As A Transistor Pre-Driver/Headphone Amp
Very clever idea. Thanks for joining us and posting. I want to keep the complete amp DC coupled if possible, and in the 0dB setting the ofset is close to 0mV, but in the 9dB setting I get more that 200mV. But this is taken care of by a 15M Ohm resister to the negative voltage. This brings the ofset ...
- Mon Oct 12, 2009 1:05 pm
- Forum: Document
- Topic: SSL Phase Meter Schematic
- Replies: 16
- Views: 32018
Re: SSL Phase Meter Schematic
Since I was never a practicing engineer my use of the "phase meter" was for setting 2 track azimuth. I almost never used it for multi track azimuth preferring the mono sum method. I'm glad I don't have to deal with tape any more. :| I could see how the SSL type which indicates correlation ...