Search found 3705 matches

by JR.
Mon Oct 17, 2011 1:23 pm
Forum: Pro Audio Design
Topic: microphone problem in a small enclosure
Replies: 6
Views: 12459

Re: microphone problem in a small enclosure

I have done some work with small cheap microphones in my drum tuner fractions of an inch from a drumhead (not being played). You need to determine if the mic is overloading mechanically from SPL, or electrically. IS SPL meter placed identically to mic? Is mic performance frequency sensitive? A respo...
by JR.
Mon Oct 17, 2011 1:14 pm
Forum: The Peabody Lounge
Topic: Residential Lighting with LEDs: Retrofitting the Pink Ranch
Replies: 149
Views: 407613

Re: Residential Lighting with LEDs: Retrofitting the Pink Ra

No.. now I must make them work.. I found in one case I had to replace a small x4 resistor array, that just wouldn't make connection. After removing it I found what looks like one bottom pad on the part, mostly gone??? I hope that isn't going to happen in production. Nothing I did to AFAIK. I had to ...
by JR.
Mon Oct 17, 2011 11:06 am
Forum: The Peabody Lounge
Topic: Residential Lighting with LEDs: Retrofitting the Pink Ranch
Replies: 149
Views: 407613

Re: Residential Lighting with LEDs: Retrofitting the Pink Ra

Since I just spent a painful weekend building up some SMD prototype PCBs and could have used better light sources, do you have any recommendations for modern bench or under-counter lighting?

JR
by JR.
Sat Oct 15, 2011 5:34 pm
Forum: The Peabody Lounge
Topic: "When We Invented the Personal Computer" Steve Jobs 1981
Replies: 2
Views: 9409

Re: "When We Invented the Personal Computer" Steve Jobs 1981

Back in the late '70s I was running my mail order kit business on software I wrote myself to run on that H-11. Each 8" floppy held 256k of data so I spread out my mailing list across 10 floppies based on first digit of zip codes, So each floppy could read, edit, then write 125k worth of address...
by JR.
Sat Oct 15, 2011 1:33 pm
Forum: The Peabody Lounge
Topic: Search Phrases
Replies: 1
Views: 4827

Re: Search Phrases

You need to get to work on that... :lol: Sometime (not now) I need to talk to you about the work involved in setting up a BB... probably next year I will try one for my day job product. If I do it right, my old customers can provide customer support and answer easy questions for new ones... While I ...
by JR.
Wed Oct 12, 2011 5:03 pm
Forum: Pro Audio Design
Topic: Wayne's 1570 summing amp
Replies: 18
Views: 29919

Re: Wayne's 1570 summing amp

Bzzt... not gonna work... Passive sum fed to a mic preamp, is a voltage feeding the gain stage. The active virtual earth sum bus, is held to a low impedance by NF. At best your mic preamp would just amplify the error voltage on the virtual earth, at worst you will cause instability in the virtual ea...
by JR.
Mon Oct 10, 2011 12:05 pm
Forum: The Peabody Lounge
Topic: "When We Invented the Personal Computer" Steve Jobs 1981
Replies: 2
Views: 9409

Re: "When We Invented the Personal Computer" Steve Jobs 1981

SJ (RIP) deserves credit for his business accomplishments, but I am uncomfortable with his deification as a master innovator. In several cases he took other peoples inventions and out executed them with improved cosmetics and full customer experience. Two obvious examples are Xerox Parc early work o...
by JR.
Thu Oct 06, 2011 2:09 pm
Forum: Pro Audio Design
Topic: Balanced Inputs
Replies: 89
Views: 155060

Re: Evolution and Origin of the SuperBal Variable Gain Input

Looking at the 6 resistor version of 5 resistor bilateral current source, I am once again curious about wether THAT has some spare resisostors hanging around on the substrates that could be repurposed. I precision low noise current source may be a limited market, but cooler than the batmobile.

JR
by JR.
Thu Oct 06, 2011 11:08 am
Forum: Pro Audio Design
Topic: Balanced Inputs
Replies: 89
Views: 155060

Re: Evolution and Origin of the SuperBal Variable Gain Input

No the Peavey/AMR was a mixed current source, with resistor feeds to L/R mix. As many as 72 current sources on the monitor side of the 24 bus console, with 40 odd resistor feeds from input side of the split. The VCA in the master section with all current source feeds was done in a earlier Loft conso...
by JR.
Wed Oct 05, 2011 5:15 pm
Forum: Pro Audio Design
Topic: Balanced Inputs
Replies: 89
Views: 155060

Re: Evolution and Origin of the SuperBal Variable Gain Input

OK the DC path is even more convoluted...kind of like following an Escher drawing. I'd need to look up the opamp's input bias currents and DC offsets,, but yes i was incorrect the 200x is AC gain. Since the DC path to ground for the input is through that current source, if there is an error current ...