Tag Archives: Equalizer

Bose® Active Equalizer Test Platform

Posted on April 13, 2016 by retrovoltage

This project is going to take a while since I’m slammed in the shop, but I’m in the process of converting a Bose® 901 Series I Active Equalizer to  a test platform. With sockets for the transistors, and clip connections … Continue reading →

Posted in Audio, Bose, DIY, Electronics, Stereo, Test Equipment | Tagged , , , , , | 3 Comments

The Speaker Spotter – Speakers of Craigslist – March 14th, 2014

Posted on March 14, 2014 by retrovoltage

There’s always something interesting for sale on Craigslist, especially in Seattle. Here’s a selection of especially notable vintage speakers and other audio products for sale on the local Craigslist. I’m not affiliated with any of these sales, but if you’re interested, you … Continue reading →

Posted in Audio, Collections, Photos, Speakers, Stereo, Vintage | Tagged , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , | 2 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 →

Posted in Uncategorized | Tagged , , , , , , , , , | 8 Comments

Bad Capacitors Strike Again

Posted on February 5, 2013 by retrovoltage

I’m working on another Bose 901 Series 1 equalizer. It looks to be the same manufacturing run as the first one I wrote up last July, uses the same components, and those components look like they’ve had the same failure … Continue reading →

Posted in Electronics, Hardware | Tagged , , , , , , , | 9 Comments

First Ever Bose 901 Series 1 Active Equalizer Repair

Posted on July 25, 2012 by retrovoltage

This post is almost 15 years old! Check out this much more recent round-up of Bose 901 Series I and II Active Equalizer repair tips and tricks, and leave a comment if you have any feedback. The post you are … Continue reading →

Posted in Electronics, Projects, Speakers, Vintage | Tagged , , , , , , , , , , , , , , , , | 37 Comments

Identifying Your Bose 901 Series 1 Equalizer

Posted on July 11, 2012 by retrovoltage

Bose 901 Series I Active Equalizers came in two varieties, which can be used interchangeably, but have fairly different circuit designs. It’s simple to tell them apart for ordering parts for a repair with a quick inspection of the inside. Both … Continue reading →

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