This Bose® 901 Series II Active Equalizer, serial number 46234, came in for a repair just recently. As is happening with nearly all of these early ’70s equalizers by now, this one had developed poor sound quality and distortion and was due for an overhaul.
This one received all new resistors, electrolytic and film capacitors, and upgraded output capacitors and silver solder. The transistors were also hand-matched to ensure equal balance and curve precision.
Fully serviced, this equalizer is better than even when new!