Bose® 901 Series VI #181070 Repair

From Rain City Audio:

This Bose® 901 Active Equalizer, Series VI, came into the shop recently. These are some of the most recently produced Active Equalizers, although they’re still potentially a few decades old at this point in time. This is only the second Series VI that’s come in for repairs to Rain City Audio. The owner reported it was intermittently crackling after playing for a while.

DSC_0281 DSC_0283 DSC_0287  DSC_0292 DSC_0295 DSC_0297

After all new caps and new op-amp chips, this one sounds great!

This entry was posted in Bose, Electronics, Hi-Fi, Stereo, Vintage and tagged , , , , , . Bookmark the permalink.

4 Responses to Bose® 901 Series VI #181070 Repair

  1. Jeremy Rouse says:

    What’s the transformer that powers this? I need to replace mine but cant identify what to get.

    • jwk says:

      A drop-in replacement is NLA, but the Tamura 3FD-336 can be configured as an exact functional replacement; primaries in parallel, secondaries in series, junction of the two secondaries becomes the center tap that goes to ground.

      • Jeremy Rouse says:

        THANK YOU! Looks like I can order the part easily online. Does it drop right in? I see the Tamura 3FD-336 is a little different orientation.

        • jwk says:

          No — the holes won’t line up — it’s electrically equivalent though. You’ll need to configure it per the product datasheet with the dual primaries in parallel, and the dual secondaries in series, to give you the 120V input + center-tapped output you need.

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