Search found 3445 matches

by JR.
Mon Aug 11, 2008 9:11 am
Forum: The Peabody Lounge
Topic: Thousands of lightning strikes
Replies: 45
Views: 87870

Re: Thousands of lightning strikes

Roger - Do you know if they flew into an obstruction or had an engine failure and had to "auto-rotate?" One would point to visibility as a possible cause the other failure. Zero visibility in a helicopter is very dangerous situation due to spatial disorientation. Engine failure in that terrain give...
by JR.
Sun Aug 10, 2008 12:21 am
Forum: Document
Topic: Old Engineering notebook
Replies: 7
Views: 11797

Re: Old Engineering notebook

My dad was sent over to England for King George's coronation in '30s and IIRC spent some time at Pinewood (?) which I think was the Brit center of film technology back then. He may have picked it up over there... At one point he had some old WE amp racked up in the basement for his Hifi I presume.. ...
by JR.
Sat Aug 09, 2008 5:52 pm
Forum: Document
Topic: Old Engineering notebook
Replies: 7
Views: 11797

Re: Old Engineering notebook

Wow, an ERPI man! I have to piece this all together from papers I have but apparently he worked at Vitaphone in '20's, ERPI on '30's, MUZAK late 40's, RCA up until his death late '50s. Vitaphone was a collaboration between Warner Bros, Western Electric and Bell Telephone labs. So I suspect most of ...
by JR.
Sat Aug 09, 2008 4:51 pm
Forum: Document
Topic: Old Engineering notebook
Replies: 7
Views: 11797

Re: Old Engineering notebook

raf wrote:Wow, that's truly amazing John....

Obviously, design runs in the family, no? Was this the first "Mobile newsreel"? Or was it for location shoots for movies?

rf
Back in the early days before television short news reels were shown in movie theaters before(?) the features.

JR
by JR.
Sat Aug 09, 2008 10:43 am
Forum: Pro Audio Design
Topic: Split Power Supply From Unipolar Using a Rail Splitter
Replies: 5
Views: 10291

Re: Split Power Supply From Unipolar Using a Rail Splitter

I recall using the 723 in my first kit back in the '70s before three terminal regulators became ubiquitous. I'm not sure I see the rationale for using the rail splitter in this design, since a real ground exists at the common point between the two capacitors. If they are trying to deal with one rail...
by JR.
Fri Aug 08, 2008 5:46 pm
Forum: Document
Topic: Old Engineering notebook
Replies: 7
Views: 11797

Re: Old Engineering notebook

AFAIK he never got a patent. I vaguely recall some of the pages may have been witnessed (signed by a co-worker). Yes, those are classic engineering notebooks. The pages are numbered for integrity of the chronological order. Gaps with pages left empty are likewise a no-no. I had a classic engineering...
by JR.
Fri Aug 08, 2008 4:44 pm
Forum: Document
Topic: Old Engineering notebook
Replies: 7
Views: 11797

Old Engineering notebook

Ok here's that notebook page I found amusing. Sketch of newsreel camera mounted in an old Ford. The actual company this work was done at is ERPI one of the sundry interrelated organizations. FWIW I didn't inherit my dad's neat handwriting or drafting chops, and I even worked as a draftsman long befo...
by JR.
Fri Aug 08, 2008 9:43 am
Forum: The Peabody Lounge
Topic: Thousands of lightning strikes
Replies: 45
Views: 87870

Re: Thousands of lightning strikes

Was that chopper crash anywhere near you?

JR
by JR.
Thu Aug 07, 2008 11:11 am
Forum: Pro Audio Design
Topic: Graeme Cohen - Microphone Amplifier History and Design
Replies: 10
Views: 32930

Re: Graeme Cohen - Microphone Amplifer History and Design

I have a picture of my dad's ham rig from before he was married... No amateur radio at the house when growing up, but I did my share of SWL. ---- IIRC early DBX VCA were selected discrete (to-92) (edit- that would be to-18) metal can transistors, wedged into a common thermal heatsink to hopefully ke...
by JR.
Thu Aug 07, 2008 8:59 am
Forum: Pro Audio Design
Topic: Graeme Cohen - Microphone Amplifier History and Design
Replies: 10
Views: 32930

Re: Graeme Cohen - Microphone Amplifer History and Design

I'm kind if busy at the moment but I have some cool stuff I can scan in... engineering sketches of movie cameras mounted into old model A (T?) Fords and such. AFAIK Muzak was not connected to RCA but a letter from the president of WE was addressed to my dad c/o MUZAK. Another data point is we actual...