Pro Audio Design Forum

This made it to my inbox and I'm reminded of a similar story once told to me involving an SSL Pipe Organ system. "Excuse me sir, but is the power supply supposed to be on fire?" http://www.eetimes.com/electronics-blogs/other/4208755/analogue-computers-to-the-rescue I'm sure Roger can relat...

Schematics for the dBx 3BX dynamic range expander. One of the first applications I saw using the non-linear capacitor. https://www.proaudiodesignforum.com/Images/jpg/3BX_small.JPG dBx 3BX Schematic Large format: https://www.proaudiodesignforum.com/Images/jpg/3BX.JPG (4.4 MB) When I had a 3BX I had t...

Thanks MIQ. Yes, the 1G gate resistor should be lowered by many orders of magnitude. In your original post you mentioned the 1512 and I responded with a 1570. Sorry wasn't paying attention. Since you're using a 1512, you will definitely want to AC-couple the FET source and drain loads to the 1512 in...

What about using a FET buffer (LSK170?) with say 2K source and drain loads and also use those loads as the 1570's bias resistors? The +/- inputs of the 1570 can be treated as independant "halves." I'm wondering if you AC couple the Rgain line (or 1570 outputs) if you can overcome the Vgs t...

True about the drop-out beween positions. In the mic preamp the gain drops to unity for a few ms between steps but it wasn't too audible. Your mastering situation however would require seemless switching. I think that was the motivation for bruno2000 (live) to use pots in his preamp build.

OK, got it. Absence of serial errors is the key IMHO.

I wished I had some of the old Kay Elemetrics attenuators...

+1 what JR. said.

The predecessor to the iPad was the hPad. Both trace their origins to garages.

http://www.amazon.com/Hewlett-Packard-F ... 654&sr=8-1

I did the calculations for the potentiometer style attenuator. I even learned Reverse Polish Notaion to do it. Thanks iPAD! I ordered the resistors and did a mock up. The good news is that I basically got it right. The bad news is that even with .1% resistors the accuracy varies more than 0.2dB per...

JR. makes a good point about Ibias. WRT the 1646 and 120X I don't recall what the typical bias current is. For 124X line receivers (FWIW PNP input) I recall it to be about 900 nA max so it would be high enough - in some cases - to click when switched. For the 1646, to maintain LF balance, I wouldn't...

OK, good. Removing the 300R in front of the 1646 should improve both it's noise floor and output balance.