Tag Archives: audiophile

Everything to Know about Bose 901 Series V Active Equalizer and Speaker Repair

Posted on October 12, 2026 by retrovoltage

A detailed look at the Bose 901 Series V speaker system and Active Equalizer, with a brief history, plus repair tips and tricks, schematics, equalizer curves, and a parts list with direct links to buy what you need. Continue reading →

Posted in Audio, Bose, DIY, Electronics, Hi-Fi, Stereo, Vintage | Tagged , , , , , , , , , , , , | 2 Comments

Everything to Know about the Bose 901 Series IV Speakers & Active Equalizer Repair

Posted on August 10, 2026 by retrovoltage

A detailed look at the Bose 901 Series IV speaker system and Active Equalizer, with a brief history and explanation, plus repair tips and tricks, schematics, a discussion of the 5 different Active Equalizer versions for this generation, and a parts list with direct links to buy. Continue reading →

Posted in Audio, Bose, DIY, Electronics, Hi-Fi, Stereo, Vintage | Tagged , , , , , , , , , , , | 5 Comments

Everything to Know about the Bose 901 Series III Speakers & Active Equalizer Repair

Posted on July 31, 2026 by retrovoltage

A look at the Bose 901 Series III speaker system and Active Equalizer, with a brief history and explanation, plus repair tips and tricks, schematics, and parts list with direct links to buy. Continue reading →

Posted in Bose, Electronics, Hi-Fi, Stereo, Vintage | Tagged , , , , , , , , , , , , , | 5 Comments

The Speaker Spotter — June 19, 2026

Posted on June 19, 2026 by retrovoltage

A recurring feature curating interesting speakers for sale on Craigslist from around the Pacific Northwest. Links to Craigslist postings might go down at any time if they’re sold or pulled from sale. Vintage Bozak B302A Speakers – Excellent $500 · … Continue reading →

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The Speaker Spotter – Speakers of Craigslist – April 4th, 2014

Posted on April 4, 2014 by retrovoltage

There’s always something interesting for sale on Craigslist, especially in Seattle. Do click the titles to see the original postings with more photos and additional information if you’re interested – otherwise, enjoy the virtual window shopping! Today we’re featuring some speakers … Continue reading →

Posted in Audio, Collections, Hi-Fi, Photos, Speakers, Stereo | Tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | Leave a comment

1977 Yamaha CR-2020 Vintage Stereo Receiver Repair

Posted on January 26, 2014 by retrovoltage

The Yamaha CR-2020 drives 120W/channel into an 8 ohm load and supports 3 pairs of speakers (but only plays 1 or 2 pairs a time), dual phono inputs supporting both moving magnet (MM) and moving coil (MC) pick-ups, tape-copy functionality … Continue reading →

Posted in Audio, Electronics, Hi-Fi, Music, Stereo, Vintage | Tagged , , , , , , , , , , , , , , | 34 Comments

Mailbag: Is The Bose 901 Equalizer Really Necessary?

Posted on October 21, 2013 by retrovoltage

I take questions from readers often, but they don’t always make it to a Mailbag segment. I’ve got this one a few times lately, though, so I figured I’d answer this one publicly. Jim from Ohio writes, I bought a … Continue reading →

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Identifying Your Bose 901 Series 1 Equalizer

Posted on July 11, 2012 by retrovoltage

Looking for the latest info on repairing your Bose 901 Series I, Series II, or Bose 800 Active Equalizer and speaker system? Take a look at the latest in-depth guide with everything you need to know (and more!) Bose 901 … Continue reading →

Posted in Electronics, Projects, Vintage | Tagged , , , , , , , , , , , | 4 Comments

New Project Idea: Oddball Tube Hi-Fi Amplifier

Posted on July 12, 2011 by retrovoltage

I’m looking for a new summer project, and think I’m going to branch off from repairing radios to building some of my own gear. I’m interested in making a tube hi-fi stereo amplifier to go with my old speakers – … Continue reading →

Posted in Electronics, Projects | Tagged , , , , , , , , , , | 3 Comments