Monthly Archives: October 2026

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

KLH Transistor Substitution Guide (“Solid State Components Cross Reference Guide”)

Posted on October 6, 2026 by retrovoltage

This post contains the transcribed text of the Februrary 1970 KLH Solid State Components Cross Reference Guide (aka, transistor substitution guide), obtained from an original copy of the document. It’s in this format because it’s easier to search and find quickly. Continue reading →

Posted in Audio, Electronics, Hi-Fi, Resources, Vintage | Leave a comment

Upcoming Projects – Q4 2026

Posted on October 5, 2026 by retrovoltage

I’m working on a few projects right now, and hope to have several of them fixed up and ready to post before the end of the year. Likely a few more ad-hoc, too. KLH Model 20 set with speakers and … Continue reading →

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The Speaker Spotter — October 2, 2026

Posted on October 2, 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. 1977 Klipsch La Scala $3,500 · Portland Someone’s … Continue reading →

Posted in Audio, Collections, Electronics, Hi-Fi, Vintage | Tagged , | Leave a comment