Pro Audio Design Forum

In typical radials, the metal can is not physically attached to either lead. I ran some experiments on large-value (Cgain) caps and found large differences in capacitance from the can to the terminals. (You would expect this but I wanted to know.) My interest was Cgain capacitors in preamps. At hig...

We figured that input and output phantom protection of line-level stages was a lot to throw in. There may be a sequel. To answer Roger's question, the published 1646 protection using bridge to rails, works fine. One thing I have found with the 1646 is that OutSmarts makes the part tolerant to stored...

John - I edit a lot of commercial modern music (head/tail trims, normalization etc.) You'd be surprised at the number of entire mixes, or elements in mixes, that have it upside down on the CD. We may now agree that pin 2 is really hot, but that doesn't solve the problem. The other day I was listenin...

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.

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...

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...

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...

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...

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 ...

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.