Tag Archives: Bose 901

Bose 901 Series II Active Equalizer #67402 Repair

Posted on August 25, 2014 by jwk

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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Bose 901 Series II Active Equalizer #103549

Posted on July 10, 2014 by jwk

This Bose® 901 Series II Active Equalizer is a part of Rain City Audio’s parts stock and got a full rebuild with upgraded parts and complete and comprehensive testing. All transistors, resistors, film and electrolytic capacitors were replaced, a new neon bulb added, and the controls cleaned and lubricated. This very detailed repair walkthrough has photos showing the drifted carbon composition resistors which can throw off the equalizer’s curve even if all the capacitors have been replaced. Click through for many more photos!

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Bose 901 Series II Active Equalizer #114743 Repair

Posted on June 26, 2014 by jwk

This Bose 901 Series II Active Equalizer got a full overhaul in the shop with all new capacitors, resistors, transistors and silicon diodes. After a thorough control cleaning, it sounds absolutely fantastic once again and should last for a long time to come.

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Bose 901 Series I Active Equalizer #41550 Repair

Posted on June 18, 2014 by jwk

This Bose 901 Series I Active Equalizer, serial #41550, came into my shop in need of an overhaul after being stored somewhere sticky for many years. After a rebuild and thorough control cleaning with high powered solvents, this equalizer performs good as new! All new capacitors, resistors, transistors and neon bulb will last for a long time to come.

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Bose 901 Series II Equalizer #58189 Repair

Posted on June 16, 2014 by jwk

This Bose 901 Series II equalizer came into my shop recently. It had one good channel, but the second channel was experiencing a large amount of distortion. No wonder why, the unit was mostly original, although it had some evidence of being serviced before.

Inside, about half the capacitors…

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Bose 901 Series II Active Equalizer Repair #126500

Posted on June 4, 2014 by jwk

This Bose 901 Series II Active Equalizer came into the shop for a complete overhaul after it suddenly stopped working entirely. While in the shop it also got upgrades to the output capacitors and added 4%-silver solder for the lowest joint resistance possible. After a full rebuild and live listening test it’s ready to go back home and serve faithfully for many years to come.

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Bose 901 Series II Active Equalizer #111058 Repair and Upgrade

Posted on April 16, 2014 by jwk

This Bose 901 Series II equalizer just came through the shop for an overhaul and upgrade. It’s in pretty good shape except for a small piece of delaminating contact paper on the side, but isn’t showing any signs of having … Continue reading →

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Bose Active Equalizer Model 800 Repair – Bose 800 Active Equalizer

Posted on April 9, 2014 by jwk

A new one for the shop, I recently worked on a Bose Active Equalizer model 800. This is very similar to the Bose 901 Series II active equalizer; the 800 series were Bose’s PA speaker series from the same model … Continue reading →

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Bose Equalizers on eBay Need Service Too: A Photo Comparison

Posted on March 31, 2014 by jwk

You’ve had your Bose 901 Series I or Series II speakers in storage for a few years, the Active Equalizer packed away with them and now you’ve pulled them out to set up your vintage system once again. Great – … Continue reading →

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Bose 901 Series I Active Equalizer #30924 Repaired

Posted on March 18, 2014 by jwk

I recently got to work on another Bose 901 Series I Active Equalizer, Serial #30924, which needed some service. It’s coming from the original owner who purchased them new in 1970, they went into storage about 10 years ago when … Continue reading →

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