Tag Archives: Bose Active Equalizer

Bose® 901 Active Equalizer Series I #17118 Repaired

Cross-Posted from the Rain City Audio Repair Blog: This Bose® 901 Active Equalizer came in through the shop for the standard overhaul service. It was showing its age, as most of these equalizers from Series I and II will do … Continue reading

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Bose 901 Series 1 Active Equalizer #46453 Repair

Cross-posted from the Rain City Audio Repair Blog: Another Bose® 901 Series I Active Equalizer came through the ship, Serial #46453. It came in with a variety of issues, just not sounding like it used to, and the owner requested … Continue reading

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Bose® 901 Series I Active Equalizer #33133 Overhaul and Upgrade by Rain City Audio

Cross-posted from the Rain City Audio Repair Blog: Another Bose® 901 Series I Active Equalizer was through the shop lately, serial #33133. It came in working well enough on its original components for an overhaul and upgrade to ensure it … Continue reading

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Bose 901 Series IV #244005 Repair by Rain City Audio

Cross-posted from the Rain City Audio Repair Blog: Bose® 901 Series IV equalizers are coming through the shop more regularly in the past year. It’s expected as these are definitely getting up there in years. This one was sounding muddy … Continue reading

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Esteemed Bose® Model 901 Active Equalizer – Serial #230 Repair

Cross-posted from Rain City Audio: I had the distinct pleasure of working on one of the earliest  Bose® Model 901 Active Equalizers from Series I’s first production run. Serial #230, in fact! It’s made entirely by hand and shows traces … Continue reading

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Bose 901 Series IV Equalizer #202245

A bit different from the run of Series I and Series II that I usually see, I got to fix up this Bose 901 Series IV Active Equalizer which was sent to me from Austin, TX. The Series IV was sold from 1978-1983 and its construction reflects this.

The PCB on this model is single-ended, so can be completely removed from the chassis.

<img class="alignnone" src="https://lh4.googleusercontent.com/-yTJ3z3swIO4/U_wH-zjcj3I/AAAAAAAAkEA/YBDKfs9GTSs/s640/IMG_1459.JPG&quot; alt="" width="640" height="480 Continue reading

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Bose 901 Series II Active Equalizer #67402 Repair

This equalizer got a full overhaul with new 1% precision resistors, electrolytic capacitors, audiophile-grade output capacitors, transistors, gold-plated RCA jacks, 4% silver solder for all connections, a thorough switch cleaning, and computerized frequency response testing and a listening burn-in to verify proper operation. It sounds just fantastic with a very dynamic and life-like presence that really draws you into the experience of the source material, just like the Bose 901 should.

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