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Category Archives: Audio
HH Scott HHS-20 “Scotsman” Receiver Overhaul
A local repeat customer recently brought in his old HH Scott HHS-20 receiver for an overhaul. It worked a few years ago when he put it away, although not without a few issues of its own, and when he dug … Continue reading
Posted in Audio, Electronics, Projects, Stereo, Vintage
3 Comments
Music Minder Automatic Power Controller for Hi-Fi Systems
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 automatic, hi-fi power, music minder, popular mechanics, record player, turntable power
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DBX SFX-10
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
5 Comments
Bose® Active Equalizer Test Platform
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 Bose, conversion, Equalizer, sockets, test platform, transistor
3 Comments
“Won’t that ruin the vintage sound?”
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 amplifier, old stereo, rich, sound signature, stereo, tone, vintage sound, warm
3 Comments
Neat Little 60FX5 Stereo Single-Ended Tube Amplifier
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
The Speaker Spotter – March 3rd, 2016
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 Bose, carver, dali, ess, jbl, kef, phase research, tannoy, the speaker spotter, totem acoustic
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The Speaker Spotter – February 14th, 2016
Another installment of the occasional series “The Speaker Spotter”, showcasing interesting speakers for sale right now on the local Seattle Craigslist. As always, I am not affiliated with any of these postings. If the linked ad doesn’t load, it’s likely … Continue reading
Posted in Audio, Collections, Speakers
Tagged Craigslist, Speakers, the speaker spotter, vintage speakers
3 Comments
Bose® 901 Series IV Active Equalizer #501554 Overhaul and Upgrade
From the Rain City Audio Repair Blog: This Bose® 901 Series IV Active Equalizer, serial #501554, came into the shop with the owner reporting that it loses output on one channel and the sound degrades the longer it is powered … Continue reading
Posted in Audio, Bose, Electronics, Projects
Tagged 901, Active Equalizer, Bose, series IV
1 Comment
Reviewing the Gemtune APPJ PA1501A 6AD10 Stereo Tube Amplifier
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 →