Bose® 901 Series I Active Equalizer #7790 Repair

From Rain City Audio:

This rare early-production Bose® 901 Series I Active Equalizer, serial #7790, came through the shop recently for an upgrade. It’s original owner bought this new in 1969 and kept it in use until it began to act up.

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This equalizer was serviced several times over its life, one of the most visible was a modification to the rear panel jacks. The owner reported this particular mod was done while he was living in Pakistan.

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The repair definitely looks interesting, but electrically, it was done very well. There were some other components replaced as well, including a few transistors..

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This one received upgraded output capacitors, and all the transistors, Zener and rectifier diodes were replaced as well.

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After all these repairs and a thorough switch cleaning, the equalizer sounds fantastic and will work well for many years to come!

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This entry was posted in Audio, Bose, Electronics, Projects, Stereo, Vintage and tagged , , , , , . Bookmark the permalink.

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