Tag Archives: diy

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

Posted on June 12, 2026 by retrovoltage

The Bose 901 Direct/Reflecting Speaker System is as polarizing as it is interesting, a unique system from the golden age of hi-fi experimentation. It’s less about perfect sonic accuracy and more about the experience of listening to your music. And … Continue reading →

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Neat Little 60FX5 Stereo Single-Ended Tube Amplifier

Posted on March 6, 2016 by retrovoltage

While digging around, I came across a really simple circuit in the RCA Receiving Tube Manual describing a 1WPC stereo amplifier using only two tubes, the 60FX5 power pentodes, and a single silicon diode. The 60FX5s have high enough gain … Continue reading →

Posted in Audio, DIY, Projects, Stereo | Tagged , , , , , | 5 Comments

Building a Better Voltage Regulator

Posted on February 17, 2016 by retrovoltage

Glancing through my feeds, I stumbled across a note on The Paleotechnologist describing a new replacement for the venerable LM7805 linear regulator IC. It turns up in a ton of devices, pretty much anything with a medium-current 5V rail including … 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 →

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