Pro Audio Design Forum

I've been taking capacitors apart longer than I can remember.. It used to be normal for axial caps that the - lead was always welded to the metal can, and the positive terminal was attached to an insulated nipple.. In typical radials, the metal can is not physically attached to either lead. I recall...

?? I was talking input and output... In general outputs require diode clamps to rails just like inputs. In fact one pretty common failure mode is output mute FETs if they don't have protection diode clamps. Again probably from static hits... Of course I don't know what THAT have built in. I recall y...

Wayne's paper seems to be focused on the energy stored up in the phantom blocking capacitors. For line level inputs in my experience the common faults come from static hits or mains power (at least in live sound reinforcement). The diode clamps can do a good job absorbing static hits, but 120-240V m...

The effective CV is the total of voltages applied to + and - CV pins simply added together, with the sign of the CV pin factored in. So counting the sign, if we send +18mV to both control pins it becomes 18-18 or 0V for unity gain. OTOH +18mV on the + pin and -18mV on the - pin, is 18 - (-18) or 18 ...

AFAIK studio equipment designers figured out that Absolute Polarity was worth preserving back in the early '80s, so gear made since then should be reliably polarity correct.. DIY or esoteric gear not so much... Prior to that it was so bad I put a polarity switch on one of my phono preamps to correct...

Interesting... in recording studio they should have pretty good handle on polarity... perhaps downstream feeds?

JR

Absolute polarity meter? I am not sure how to do this in a receive only environment. We can make assumptions about acoustic instruments wrt typical waveform asymmetry but I don't feel lucky to come up with a reasonable algorithm.

JR

Thanks,, Wish I could have made the show.. but I'm actually getting some work done.

I was nervous how PK/VU would be received by your conservative, luddite, "no digital for me" customers Have any asked to defeat it or can we remove that switch?

Later..

JR

Hi Wayne... congrats on getting published in AES. 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...

The two gain control ports can be thought of as + and - inputs that sum together to control the VCA gain. For simple applications where you aren't calling for much gain range it is cheaper/easier to just leave one control port grounded and drive just the other one. For console fader automation where...