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Magnetic Tape and the Emergence of High-Fidelity Recording

By Denny Sanders on Oct 18, 2017 12:00:00 PM

In the earliest days of sound recording (late 1880s to 1926), all recordings were made acoustically. That is to say, a recording machine with a large horn with a needle on the other end was set before an orchestra and the vibrations from the needle would “draw” a pattern on a spinning wax cylinder (or later flat disc). If a vocalist was called upon to sing, they would stand before the horn and sing right into it.

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Topics: Vintage Electronics, Vintage Audio Technology, Broadcast History

Found in the Attic: Shure M67 Mic Mixer

By Tom Vernon on Nov 11, 2016 5:00:00 PM

Some pieces of broadcast equipment are destined to become classics. The Otari MX5050, Gates Sta-Level and Spotmaster 500 cart machines come to mind. All were rugged, easy to service, and affordable. And so is our current attic discovery, the Shure M67 microphone mixer.

The story begins almost 50 years ago, in 1968 when the M67 was introduced. Production continued through 1987. In 1968, many stations were still using portable mixers with vacuum tubes, so an upgrade to solid state was a plus. One of the early footnotes in the history of the M67 was its use in the recording of Woodstock in 1969.

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Topics: Vintage Audio Technology

Found in the Attic: Comrex Buddy Remote Mixer

By Tom Vernon on Sep 19, 2016 9:44:00 AM

During the Dark Ages, before the coming of the Internet, most remote broadcasts involved the use of leased telephone lines. Usually these lines were installed by the phone company a few days before the broadcast. Typically, they ran from the remote site to the central office (CO), and from there, to the studios. Voice grade lines were usually ordered, sometimes they were equalized, sometimes not, depending on the distances involved. The good thing about these lines is they provided a guaranteed quality of service (QoS), i.e. if they didn't work, the phone company had to make it right. The bad news was that they required advance lead time with the phone company, and there was a cost for the use of these lines and their setup. If there were weekly sports remotes, these costs could easily add up. Normally this was just added to the sports budget. But there was an alternative for the budget minded.

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Topics: Vintage Audio Technology

Found in the Attic: Singer TTG-3 Two-Tone Audio Generator

By Tom Vernon on Sep 7, 2016 1:15:00 PM

Many of the items featured in Found in the Attic are familiar staples of the broadcast, test equipment or consumer electronics industries. But sometimes we feature the obscure. This is one of those times, as we revisit a college surplus grab from the 1970s, and look at the Singer Two-Tone Audio Generator Model TTG-3.

Part of what makes this device obscure is that it wasn't designed as a stand-alone piece of test equipment. Rather, it was a plug-in component of the Singer Panoramic Model SSB-50 Single Sideband Analyzer System. Since it is a two-tone generator, it could be used for single or two-tone modulation of single-sideband transmitters, intermod distortion tests, harmonic distortion tests, and general troubleshooting.

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Topics: Vintage Electronics, Vintage Audio Technology

Found in the Attic: Hallicrafters S-20 'Sky Champion' receiver

By Tom Vernon on Jul 19, 2016 10:29:00 PM

This installment of Found in the Attic examines the Hallicrafters S-20 'Sky Champion' receiver. The 'Sky Champion' line was the company's' mid-priced communications receiver.   Introduced in 1938, the S-20 was replaced by the S-20R in 1939. Since it was in production for less than a year, these receivers are somewhat rare.

There are several differences between the S-20 and S-20R. The S-20 primarily used tubes with grid caps, while the later S-20R used newer replacements. Tube lineup for the S-20 includes: 6K7, RF stage; 6L7, 1st detector-mixer; 6J5, HF osc; 6K7, IF amp; 6Q7, 2nd detector-AVC-1st audio stage; 6F6, audio out; 6J5, BFO and 80, rectifier.

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Topics: Vintage Electronics, Vintage Audio Technology

Found in the Attic: Stanton RM-THREE Disco Mixer

By Tom Vernon on Apr 19, 2016 11:30:00 PM

The Stanton RM-THREE disco mixer is such a recent device that it almost doesn't qualify as a Found in the Attic item, even though that is where it has lived for the past decade. It dates from the late 1990s. This Stanton, along with its successor, the RM-3S, have long been out of production. But it recalls the purpose-built disco mixers, and a time when the turntable began its transition from a device to playback recorded media into a creative tool in its own right.

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Topics: Vintage Electronics, Vintage Audio Technology

Found in the Attic: RCA Victor 45-J-2 Turntable

By Tom Vernon on Dec 28, 2015 12:27:16 PM

An earlier installment of Found in the Attic examined the ATC-Collins P-190, the first commercially produced cart machine. The point was made that the fast-paced Top-40 format would not have been possible without this device. The same can be said for 45 RPM records. The difference is that the cart machine was designed for radio from day one, while the 7-inch record began as a consumer medium. It wasn't long though, until it became the mainstay of Top 40 music.

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Topics: Vintage Audio Technology

Found in the Attic: Allison Research Model 650 Noise Generator

By Tom Vernon on Apr 29, 2015 3:30:00 PM

Back in the days when radio was powered by analog circuits, noise was usually considered a bad thing. Along with distortion and frequency response, it was measured as part of a station's annual proof-of-performance, and eliminated at every opportunity. But there are times when noise can be put to good use. As a test signal, noise can be used to analyze room acoustics, do a rapid frequency response assessment, and tune up audio processors. Since noise has energy present in all frequencies at all times, it can be used to rapidly assess frequency response.

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Topics: Vintage Audio Technology

Found in the Attic: Realistic 12-1875A 8-Track/Stereo Cassette Adapter

By Tom Vernon on Sep 28, 2013 3:04:00 PM

In this occasional series, our resident technical archaeologist, Tom Vernon, explores some of the vintage gear found in the recesses of his storage space. This post is from the era when 8-Track ruled.

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Topics: Vintage Audio Technology, Electronics


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