Tag Archives: Equalizer

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

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Bose® 901 Series II Active Equalizer #117185 Overhaul

From the Rain City Audio Repair Blog: Another Bose® 901 Series II Active Equalizer came through for an overhaul and some upgrades. These equalizers are necessary to provide the curve shaping needed to get the great sound the 901 Direct/Reflecting … 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 II Active Equalizer #111058 Repair and Upgrade

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 Equalizers on eBay Need Service Too: A Photo Comparison

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

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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The Speaker Spotter – Speakers of Craigslist – March 14th, 2014

There’s always something interesting for sale on Craigslist, especially in Seattle. Here’s a selection of especially notable vintage speakers and other audio products for sale on the local Craigslist. I’m not affiliated with any of these sales, but if you’re interested, you … Continue reading

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Bose 901 Series II Active Equalizer #120325 Repaired

I recently had the opportunity to work on another Bose 901 Active Equalizer, Series II. This particular model had been in service for a long time in active use and was showing its age. It was sent back to Bose … Continue reading

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Bose 901 Active Equalizer #20262 Repaired!

This Bose 901 Series I Active Equalizer came to me from North Carolina, where it had been stored in original packaging for many years. Unfortunately even with careful storage the equalizer wasn’t in running condition and it looks like the … Continue reading

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Bose 901 Series I Early Production Equalizer Full Repair

I just had another Bose 901 Series I equalizer through the shop for the standard service. It didn’t have a visible serial number, but is definitely a very early production version. The Active Equalizer was revised once through the model’s … Continue reading

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