My Dad, Dave Johnson was an audiophile in a time before the word came into widespread use. An avid fan of modern Jazz in his youth, he came of age in the 1950s. While 33 1/3 RPM records were well established as the contemporary standard, stereo had not yet come to market. I’m not sure what year it was when he built his audiophile stereo system but it was around the time that stereo records were just starting to become available starting in 1958. It was made up of a pair of Heathkit Preamplifiers, a pair of 20/25 Watt Heathkit Power Amplifiers, a Music Master Idler Drive Turntable and a pair of 2 way speaker cabinets he built from scratch. Here are some pictures of the amps and turntable…
The Power Amplifier…
No photos of the long gone speaker cabs though.
I have many fond memories of listening to that system as a child
The following entertaining Astronomical information is provided in full by the B612 Foundation
B612 Impact Video 4-20-14 H264 from Spine Films on Vimeo.
Between 2000 and 2013, a network of sensors that monitors Earth around the clock listening for the infrasound signature of nuclear detonations detected 26 explosions on Earth ranging in energy from 1 to 600 kilotons – all caused not by nuclear explosions, but rather by asteroid impacts. These findings were recently released from the Nuclear Test Ban Treaty Organization, which operates the network.
To put this data in perspective, the atomic bomb that destroyed Hiroshima in 1945 exploded with an energy impact of 15 kilotons. While most of these asteroids exploded too high in the atmosphere to do serious damage on the ground, the evidence is important in estimating the frequency of a potential “city-killer-size” asteroid.
A list of the impacts shown in the video can be found here.
For more information on this data, please check out our Impact Video FAQ.
You can read or download the press release about today’s event here.