I remember that beast. Had huge rising THD within the audio band, presumably from the designer's belief that since 901s have no tweeters, the hash wouldn't be audible! Had a monster power supply, lots of SOA to run parallel pairs and handle the EQ requirements. This was introduced to be used with 901 Series II, which was a sealed box...subsequent models (injection molded vented cabs) were more sensitive, had a less severe bass EQ, and they stopped making this amp. Don't bother unless you have 2 pairs of Series IIs in good working order, and a room well suited to their proper use! Will probably sound like a** with any modern high res speaker.
bose 1801 amplifier
i have the chance of buying the bose 1801 amplifier which was part of the 'super bose system' which needed 4 901's! should i buy it???