Author Archives: retrovoltage

Burned Up Aiphone

Posted on March 10, 2011 by retrovoltage

This is what happens when you connect the high level output of an audio amplifier, to an input designed to be hooked up to an MP3 player or other line level audio source. This Aiphone PA amplifier was incorrectly installed … Continue reading →

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Seeking Information: 1941 Stromberg-Carlson 520 Radio

Posted on February 16, 2011 by retrovoltage

If anyone reading this has information about a Stromberg-Carlson 520-PG from 1941, I would appreciate if you contacted me. I’ve been trying to find a photo of one that someone else owns, or even a picture of one in a … Continue reading →

Posted in Commentary, Radios and Tubes, Vintage | Tagged , , , | 7 Comments

Antique Capacitor Color Code Chart

Posted on February 16, 2011 by retrovoltage

I’m working on restoring another radio, and it has antique capacitors with color code markings that are different from the commonly used 3-digit codes found today. It took a bit of searching to find a good chart with these, so … Continue reading →

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Project Idea: Digital Vacuum Tube Tester

Posted on February 15, 2011 by retrovoltage

I’m in the early stages of brainstorming another project idea that will combine vacuum tubes with modern microelectronics in a useful and innovative way: a computerized vacuum tube tester. Tube testers themselves aren’t very complicated devices – the simple ones, … Continue reading →

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Antique Radio in “Firefly” Episode 2

Posted on February 7, 2011 by retrovoltage

I was watching Firefly the other day, and noticed something interesting. Firefly is set in the year 2517 centered around a small smuggling ship named Serenity manned by a crew of mercenaries, former freedom fighters, a pair of escaped convicts, … Continue reading →

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Found: His Master’s Voice (HMV) 444 Radio

Posted on February 3, 2011 by retrovoltage

I’ve added a new radio to my collection, and I think I have a new favorite. This 1934 His Master’s Voice model 444 is a small 5-tube console with Medium-Wave (MW, also known as AM Broadcast) and Long-Wave bands in … Continue reading →

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Refurbishing a Capacitance Tester

Posted on January 20, 2011 by retrovoltage

Parts Express sent me an advertisement for a $45 capacitance meter today. This actually a pretty good deal, and it’s a useful thing to have around if you’re doing electronics work. I’d probably have bought one myself, if I didn’t … Continue reading →

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Cost Engineering in 2011

Posted on January 18, 2011 by retrovoltage

Cost engineering to pick the exact right time of failure has gotten considerably more precise since then. The warranty on the array controller in my enterprise backup server expired on Jan. 2, 2011 – just over two weeks ago. Today, … Continue reading →

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Cost Engineering in the 1930s

Posted on January 15, 2011 by retrovoltage

It looks like cost engineering was already happening back in the 1930s: In the foreground, the destroyed original power transformer from the 1939 Zenith 7-S-363 radio; the rear, an equivalently rated replacement built in October 2010 by Edcor Transformer. In order … Continue reading →

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Repairing a Vintage Radio (Coronado 907)

Posted on January 13, 2011 by retrovoltage

This is my first project, a 1940 Coronado model 907. This was originally a “high end low end” receiver: it only receives the AM broadcast band, but has three tone settings and mechanical push-button presets. It also uses 7 tubes … Continue reading →

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