Tag Archives: Technology

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 , , , , , , , , , , , | 3 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 , , , , , , , , , , , , , | 4 Comments

How to Buy Capacitors on Mouser.com

Posted on June 29, 2026 by retrovoltage

Learn about searching for electrolytic, film, and ceramic capacitors on popular parts house Mouser.com, with examples to help you get started selecting the right parts. Don’t risk counterfeit parts from 3rd-party suppliers – go right to the source! Continue reading →

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The Speaker Spotter — June 26, 2026

Posted on June 26, 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. We’re a little lighter this week with only … Continue reading →

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Everything to Know about Bose 901 Series I and Series II Active Equalizer Repair & Speaker Systems (and the 800, too!)

Posted on June 12, 2026 by retrovoltage

A deep dive into the history and repair of Bose 901 Series I and II, plus the Bose 800, sourced from direct experience repairing more than 500 Active Equalizers. Includes vintage ad copy, photos, tips and tricks, schematics, and parts lists. Continue reading →

Posted in Audio, Bose, Collections, Resources | Tagged , , , , , , , , , , , , , , | 5 Comments

Upcoming Projects for 2026

Posted on June 2, 2026 by retrovoltage

Having had a chance to unpack some of my shop from storage and settle in to the new space, I’ve got an idea of what projects I’ll be working on myself in between projects with my shop partner. Bose Active … Continue reading →

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Build Log and Review: Mable Audio VT-86PP Kit Hi-Fi Amp Project

Posted on March 30, 2012 by retrovoltage

About a year ago, someone left a comment that really looked like spam on one of my pages advertising a web store selling tube audio gear and parts for guitar and audio amplifiers. Against everything I’ve ever learned about behaving … Continue reading →

Posted in Electronics, Hardware, Photos, Projects, Radios and Tubes, Technology | Tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | Leave a comment