Author Archives: retrovoltage

New Bench Gear: September 2026

Posted on September 4, 2026 by retrovoltage

A few new pieces of gear join the bench in September 2026: an HP 53181A frequency counter, and a Tektronix 434 Storage Oscilloscope. Continue reading →

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The Speaker Spotter — August 14, 2026

Posted on August 14, 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. Some really interesting, highly unusual things in today’s … Continue reading →

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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 →

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The Speaker Spotter — August 7, 2026

Posted on August 7, 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. Slightly fewer in today’s roundup than usual, but … Continue reading →

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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 →

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The Speaker Spotter — July 31, 2026

Posted on July 31, 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. klipsch la scala industrial split $2,300 · Eugene … Continue reading →

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1961 Audax CA-70 “Sonoteer” Speaker Refurbish

Posted on July 22, 2026 by retrovoltage

This set of 1961 Rek-o-Kut Audax CA-70 Sonoteer speakers got a full overhaul inside and out. Come learn about these interesting mid-century open baffle hi-fi speakers from a little known manufacturer and see how they turned out with detailed interior and exterior photos, and the original advertisement from September 1961. Continue reading →

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The Speaker Spotter — July 10, 2026

Posted on July 10, 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. There’s a few interesting things in here today, … Continue reading →

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The Speaker Spotter — July 3, 2026

Posted on July 3, 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. Today’s roundup features several listings from Olson’s Hifi … Continue reading →

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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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