Find:
About Me
Blogs
- Antique Radio Blog
- Arcane Radio Trivia
- Audio Tweak
- Audioklassiks
- BuildLounge
- Classic Receivers
- Coffman Labs Blog
- Confessions of a Part-Time Audiophile
- EEVBlog
- Engineering Radio
- Glowbugs Times
- Glowbugs Web
- Guitar Fool
- Hack a Day
- HeavyDIY
- High on Solder
- Ilektronx
- MicroSyl
- Nick's Radio Corner
- Old Stock Audio
- Pragmaddux
- Radio Stuff
- Radio Time Traveller
- Richard Sears, Vintage Electronics
- Seventies Stereo
- The Paleotechnologist
- The Signal Path
- Tube Addict
- TubeSound
Friends
Resources
- 901
- Active Equalizer
- amplifier
- Antique
- antique radio
- audiophile
- Bose
- Bose 901
- Bose Active Equalizer
- Bose Equalizer
- bose equalizer repair
- bose repair
- capacitor
- capacitor replacement
- cost engineering
- Craigslist
- eBay
- Equalizer
- fried electronics
- GE
- General Electric
- grunow
- grunow 586
- grunow 589
- grunow chassis 5-U
- grunow radio restoration
- ham radio
- hf
- hi-fi
- hifi
- HP
- KN0CK
- LCD
- old radio
- oscilloscope
- overhaul
- philco
- photos
- power supply
- preamp
- projects
- radio
- rca
- repair
- replacement
- restoration
- RTL-SDR
- RTLSDR
- SDR#
- seattle vintage radio repair
- Series 1
- series I
- series II
- series IV
- shortwave
- soldering
- Sony
- Speakers
- speaker spotter
- stereo
- stromberg-carlson
- test equipment
- transistor
- transistor radio
- tube
- Tube Amp
- tube radio
- up-converter
- Upconverter
- vacuum tube
- vintage
- vintage ad
- vintage radio
- Westinghouse
- zenith
Categories
January 2023 S M T W T F S 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Meta
Tag Archives: series IV
Bose® 901 Series IV Active Equalizer #509052
From Rain City Audio: This Bose® 901 Series IV Active Equalizer, #509052, was just purchased and sent to Rain City Audio for an overhaul. This unit was originally a 220V model but had already been converted to 110V on a … Continue reading
Bose® 901 Series IV Active Equalizer #265335 Overhaul
From Rain City Audio: This Bose® 901 Series IV Active Equalizer, #265335, just came through the shop for an overhaul. It’s owner bought this equalizer as a part of getting his Bose® system back up and running and sent it … Continue reading
Posted in Audio, Bose, Electronics, Hi-Fi, Projects, Vintage
Tagged 265335, 901, Active Equalizer, Bose, series IV
Leave a comment
Bose® 901 Series I Active Equalizer #9724 Overhaul and Upgrade
From Rain City Audio: This rare early-production Bose® 901 Active Equalizer, serial #9724, came through the shop recently for an overhaul. It’s owner reported that both channels would cut out intermittently, the switches were noisy, and the power lamp was … Continue reading
Posted in Audio, Bose, Electronics, Projects, Vintage
Tagged 901, 9724, Active Equalizer, Bose, repair, series IV
Leave a comment
Bose® 901 Series IV Active Equalizer #223227 Overhaul
From Rain City Audio: This Series IV Active Equalizer, #223227, just came through for an overhaul. The owner reported it wasn’t making any sounds, just providing a DC offset on the output jacks which was giving his power amplifier some … Continue reading
Posted in Audio, Bose, Electronics, Projects, Vintage
Tagged 223227, 901, Active Equalizer, Bose, series IV
Leave a comment
Bose® 901 Series IV Active Equalizer #253288 Overhaul
This Bose® 901 Series IV Active Equalizer came through the shop for a full overhaul. Inevitably over the years, various parts wear out and degrade and can make the equalizer sound bad – or not work at all. Without the … Continue reading
Posted in Audio, Bose, Electronics, Hi-Fi, Projects, Vintage
Tagged Active Equalizer, Bose, repair, series IV
Leave a comment
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
Bose® 901 Series IV Active Equalizer #219533 Overhaul
From the Rain City Audio Repair Blog: This Bose® 901 Series IV Active Equalizer, serial #219533, came through the shop for an overhaul. The owner was reporting the left channel went out, so it’s clearly time for an overhaul! A … Continue reading
Posted in Audio, Bose, Electronics, Projects, Vintage
Tagged 901, Active Equalizer, Bose, series IV
Leave a comment
Bose® 901 Series IV Active Equalizer #269557 Repaired
From the Rain City Audio Repair Blog: Another Bose® 901 Series IV Active Equalizer came in through the shop for an overhaul recently. This one was a bit unusual, and represents a fairly significant deviation from the published service manual. … Continue reading
Posted in Audio, Bose, Electronics, Projects
Tagged 901, Active Equalizer, Bose, series IV
Leave a comment
Bose® 901 Series IV Active Equalizer #221114 Repaired
From the Rain City Audio Repair Blog: Another Bose® 901 Series IV Active Equalizer came through the shop, this one serial #221114. It’s owner reported that it had lost one channel, so it was clearly due for an overhaul. It … Continue reading
Posted in Audio, Bose, Electronics, Projects, Vintage
Tagged 901, Active Equalizer, Bose, capacitor, overhaul, rebuild, replacement, series IV
Leave a comment
Bose® 901 Series IV Active Equalizer #244305 Repaired
Cross-posted from the Rain City Audio Repair Blog: Even the later series Bose® Active Equalizers are getting older, and the Series IV is coming up more and more. I just had another one through the shop, this one sent to … Continue reading
Posted in Audio, Bose, Electronics, Hi-Fi, Projects, Vintage
Tagged 901, Active Equalizer, Bose, series IV
Leave a comment
RETROVOLTAGE 