Author Archives: retrovoltage

A Surprise in a Re-Stuffed Capacitor

Posted on October 18, 2016 by retrovoltage

I was recently re-stuffing some capacitors for a radio. It’s not something I do often, but I’ve accumulated a pile of pulled vintage caps over the years so I have some on hand if a customer requests the most detailed … Continue reading →

Posted in DIY, Electronics, Radios and Tubes, Vintage | Tagged , , | 3 Comments

Music Minder Automatic Power Controller for Hi-Fi Systems

Posted on August 24, 2016 by retrovoltage

Mixed in with some other gear I’m servicing, I found this old Music Minder power box. It’s not all that obvious what it’s for at first glance! Some digging around found an explanation in the June 1958 issue of Popular … Continue reading →

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

Reviewing the Gemtune APPJ PA1501A 6AD10 Stereo Tube Amplifier

Posted on August 17, 2016 by retrovoltage

I recently picked up an interesting little tube amp via a group buy on Massdrop, the Gemtune APPJ PA1501A stereo tube amplifier. Try saying that three times fast! It’s a cute little single-ended stereo tube amp using a pair of 6AD10 … Continue reading →

Posted in Audio, Commentary, Electronics, Hi-Fi, Stereo, Toys | Tagged , , , , , , | 15 Comments

Would you look at that!

Posted on August 9, 2016 by retrovoltage

It’s pretty, but this 12BA6 tube has amplified for the last time. Vacuum failure has led to a gas intruding into the vacuum, and it makes a great light show when it’s being tested! As cool as it looks, this would cause … Continue reading →

Posted in Photos, Radios and Tubes, Vintage | Tagged , , , | 1 Comment

Bad Caps in Everything

Posted on July 20, 2016 by retrovoltage

I just had a bit of a scare with my Audio Precision analyzer. The 2004-era Dell OptiPlex GX270 which drives the AP hardware decided it would refuse to power up – just flashing the “ON” light for a fraction of … Continue reading →

Posted in Computers, DIY, Electronics, Test Equipment | Tagged , , , , | 3 Comments

DBX SFX-10

Posted on May 31, 2016 by retrovoltage

I saw this interesting set of speakers on Craigslist, but they sold quickly before I could investigate. They’re the DBX SFX-10s. There’s a very interesting article about their design in the May 1990 issue of The BAS Speaker, the publication … Continue reading →

Posted in Audio, Electronics | 6 Comments

Bose® Active Equalizer Test Platform

Posted on April 13, 2016 by retrovoltage

Looking for the latest info on repairing your Bose 901 Series I, Series II, or Bose 800 Active Equalizer and speaker system? Take a look at the latest in-depth guide with everything you need to know (and more!) This project … Continue reading →

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

“Won’t that ruin the vintage sound?”

Posted on March 16, 2016 by retrovoltage

Audio as a hobby sits in an interesting place in the world. There are hard numbers and objective measurements made with lab equipment on one end, and on the other end you have the subjective and variable linguistic descriptions assigned … Continue reading →

Posted in Audio, Commentary, Electronics, Hi-Fi, Vintage | Tagged , , , , , , , | 3 Comments

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

The Speaker Spotter – March 3rd, 2016

Posted on March 3, 2016 by retrovoltage

Some interesting stuff on Craigslist in this week’s The Speaker Spotter, a curated selection of Seattle’s local speakers for sale online. As always, Retrovoltage is not affiliated with any of these sellers and you should click through the link to the … Continue reading →

Posted in Audio, Collections, Speakers, Stereo | Tagged , , , , , , , , , | Leave a comment