Category Archives: Hi-Fi

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

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 →

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Accuphase C-200 Professional Pre-Amp Full Overhaul

Posted on April 16, 2015 by retrovoltage

When Kenwood’s engineers left to form Kensonic, they really brought their A-game, and this Accuphase C-200 pre-amp is no exception. It’s a mammoth device, built with exceptional attention to detail and top of the line components throughout. The owner reported … Continue reading →

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1960 Grundig SO191 Stereo Hi-Fi Console Repair

Posted on February 27, 2015 by retrovoltage

Updated July 2026 with some additional photos from the archive, and schematics at the bottom. This was a pretty early repair from back in the shop days so there’s a few things I’d do more cleanly for a customer today, … Continue reading →

Posted in Audio, Hi-Fi, Projects, Vintage | Tagged , , , , , | 31 Comments

Harman-Kardon Citation 12 Deluxe Professional Power Amplifier Refurbishment

Posted on January 12, 2015 by retrovoltage

Matching the Harman-Kardon Citation 17S professional pre-amplifier shown previously, this Citation 12 Deluxe power amplifier is its 120W per channel companion. It came to the shop for a preventive rebuild after serving for quite a few years. The owner had the … Continue reading →

Posted in Audio, Electronics, Hi-Fi, Projects, Stereo, Vintage | Tagged , , , , , | 1 Comment

Sherwood S2000-III Tube FM Tuner Repair

Posted on January 8, 2015 by retrovoltage

Sherwood made some excellent hi-fi FM tuners back in the day, and this S2000-III is no exception. Unfortunately, there’s not a lot of documentation about this model available, but that didn’t stop it from getting an overhaul and alignment. The … Continue reading →

Posted in Audio, Electronics, Hi-Fi, Radio, Radios and Tubes, Vintage | Tagged , , , , | 1 Comment

Watch a McIntosh Tube Amp Come to Life

Posted on December 27, 2014 by retrovoltage

Discovery’s How It’s Made shows us how a McIntosh vacuum tube audio amplifier comes to life: http://www.youtube.com/watch?v=2HgS6gvokEI Definitely worth watching!

Posted in Audio, Commentary, Hi-Fi, Radios and Tubes, Stereo | Tagged , , , , , | Leave a comment

Sony TA-5650 VFET Integrated Stereo Amplifier Overhaul

Posted on December 18, 2014 by retrovoltage

I recently got to work on a very interesting piece of vintage stereo gear from the golden age of hi-fi in the ’70s, the Sony TA-5650 VFET Integrated Stereo Amplifier. It’s a little rough, and while the power amp section … Continue reading →

Posted in Audio, Electronics, Hi-Fi, Projects, Vintage | Tagged , , , , , , , , , | 1 Comment