Category Archives: Electronics

1950s Motorola Modded Standalone Tube Amplifier Measurements

Posted on July 6, 2015 by retrovoltage

I had an unusual project through the shop recently. It’s a Magnavox tube amp from the late 1950s. The owner brought it in reporting he’d purchased the amplifier, pulled from a damaged console stereo and modified to be a standalone … Continue reading →

Posted in Audio, DIY, Electronics, Hi-Fi, Projects, Radios and Tubes, Vintage | Tagged , , | 3 Comments

1974 Sony STR-6200F Receiver Overhaul and Alignment

Posted on June 19, 2015 by retrovoltage

I recently got to work on a pretty big, fairly rare Sony receiver from 1973-74: the STR-6200F. It’s a powerful receiver featuring 60W per channel of power available, with quite a few inputs and outputs, and a strong FM tuner … Continue reading →

Posted in Audio, Electronics, Hi-Fi, Projects | Tagged , , , , , , , , | 4 Comments

Marantz 2270 Stereophonic Receiver Overhaul and Adjustment

Posted on May 26, 2015 by retrovoltage

I recently got to work on another iconic piece of hi-fi history, the Marantz 2270 stereo receiver. I’ve had this model through my shop before, as well as a couple of other 22xx receivers and they’re well built and generally … Continue reading →

Posted in Audio, Electronics, Hi-Fi, Projects, Stereo, Vintage | Tagged , , , , , | 4 Comments

Need 45V batteries for your old radio?

Posted on May 21, 2015 by retrovoltage

Rayovac has been making batteries for over 100 years, and their batteries were commonly found in use with many types of battery-operated tube radios. Most commonly, radios would operate on 45V batteries with a tap half-way (for 0-22.5-45V). Two in … Continue reading →

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Yamaha B-2X Check-Up and Adjustment

Posted on May 13, 2015 by retrovoltage

I recently had this Yamaha B-2X through the shop. It’s a massive beast of a power amplifier from the late ’80s, delivering up  to 170W per channel with 0.002% THD. Being somewhat more recent, this one just needed a quick … Continue reading →

Posted in Audio, Electronics, Hi-Fi, Projects, Stereo | Tagged , , | Leave a comment

Extracting Screenshots from the HP 3585A Spectrum Analyzer

Posted on April 22, 2015 by retrovoltage

I’ve posted a few times about my HP 3585A spectrum analyzers over the past several months, and after chipping away at the problem I’ve finally solved the screenshots issue! It boiled down to a bad GPIB cable for my National … Continue reading →

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Telefunken Bajazzo Sport 201 Transistor Radio

Posted on March 30, 2015 by retrovoltage

I don’t typically service portable transistor radios, but I make an occasional exception for something especially unique or interesting. The Telefunken Bajazzo Sport 201 is no exception – it’s a high end piece of German engineering, a great performer with … Continue reading →

Posted in Electronics, Projects, Radio, Vintage | Tagged , , , , , | 8 Comments

Sony TA-5650 Full Re-Cap and Adjustment

Posted on March 4, 2015 by retrovoltage

I recently got to work on another of the Sony VFET line of integrated amplifiers, the Sony TA-5650. I’ve had one through the shop previously, and this one came in for the same service. It came in running fine – … Continue reading →

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Fun with the HP 3585A Spectrum Analyzer

Posted on March 2, 2015 by retrovoltage

I spent some time playing around with one of my HP 3585A spectrum analyzers over the weekend to get a feel for its capabilities. While it’s only good from 20 Hz – 40 MHz, it’s a very capable tool within … Continue reading →

Posted in Electronics, Gadgets, Test Equipment | Tagged , , , | 1 Comment

Bose® 901 Series VI Active Equalizer #199732 Repaired

Posted on February 20, 2015 by retrovoltage

A first for my shop, I recently worked on a Bose® 901 Series VI Active Equalizer! These are considerably newer than the Series I-IV that typically come through the shop, although they’re still getting to be 25+ years old at … Continue reading →

Posted in Audio, Bose, Electronics, Projects, Vintage | Tagged , , , , , | 1 Comment