Search found 5449 matches

by mediatechnology
Fri Sep 24, 2010 4:28 pm
Forum: Pro Audio Design
Topic: THAT1646 Current Booster and Transformer Driver
Replies: 45
Views: 128224

Re: THAT1646 Current Booster and Transformer Driver

emrr wrote:I don't see any need to use build-out R between 1646 and filter at all.
I think that the output impedance in the parallel SE drive configuration is 12.5 Ohms. So pretty darn low and essentially no buildout. Glad this worked out.
by mediatechnology
Fri Sep 24, 2010 4:11 pm
Forum: Pro Audio Design
Topic: console grounding
Replies: 12
Views: 20461

Re: console grounding

On a protoboard it's easy to have pin 3 telescope. Let me add the words "and it oscillate." to the end of that sentence. One distinction that can be made to reduce confusion - and JR was able to define the two elegantly - is that there's ground and "zero signal reference." BTW l...
by mediatechnology
Fri Sep 24, 2010 3:51 pm
Forum: The Peabody Lounge
Topic: PSU Enfuego: Exploding Power Supply Story in EE Life
Replies: 1
Views: 5315

PSU Enfuego: Exploding Power Supply Story in EE Life

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...
by mediatechnology
Mon Sep 20, 2010 11:01 am
Forum: Document
Topic: dBx 3BX Three Band Dynamic Range Expander
Replies: 8
Views: 18811

dBx 3BX Three Band Dynamic Range Expander

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...
by mediatechnology
Fri Sep 03, 2010 8:16 am
Forum: Pro Audio Design
Topic: THAT 1570 1510 and 1512 Input/Output Circuits
Replies: 22
Views: 54839

Re: THAT 1570 1510 and 1512 Input/Output Circuits

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...
by mediatechnology
Thu Sep 02, 2010 6:45 pm
Forum: Pro Audio Design
Topic: THAT 1570 1510 and 1512 Input/Output Circuits
Replies: 22
Views: 54839

Re: THAT 1570 1510 and 1512 Input/Output Circuits

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...
by mediatechnology
Fri Aug 20, 2010 12:39 pm
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 271
Views: 620668

Re: Mid Side M-S Matrix Uses No Precision Resistors

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.
by mediatechnology
Fri Aug 20, 2010 12:30 pm
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 271
Views: 620668

Re: Mid Side M-S Matrix Uses No Precision Resistors

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

I wished I had some of the old Kay Elemetrics attenuators...
by mediatechnology
Fri Aug 20, 2010 11:45 am
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 271
Views: 620668

Re: Mid Side M-S Matrix Uses No Precision Resistors

+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
by mediatechnology
Fri Aug 20, 2010 7:09 am
Forum: Pro Audio Design
Topic: Mid Side M-S Matrix Uses No Precision Resistors
Replies: 271
Views: 620668

Re: Mid Side M-S Matrix Uses No Precision Resistors

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...