73max OP
Autoformer vs Speaker impedance Curve
Just don’t get sucked into the McIntosh propaganda, or others hype here.
They (autoformers) allow an amp to work with a speaker that it normally wouldn’t be a good match for.
Better to rather spend the money and get the RIGHT AMP instead of putting a "soft comfort cushion" (autoformer) between the amp and speaker.
Your B&W 802D3 deserve better than this, get the right amp for them.
https://www.stereophile.com/images/616BW802fig1.jpg
" B&W 802D3 The magnitude drops to 3 ohms between 100 and 130Hz, and again between 670 and 770Hz; and while the electrical phase angle is low in the lower region, it becomes increasingly inductive above 600Hz, reaching +46° at 1kHz, where the magnitude is 4 ohms. There is also a combination of 4 ohms and –64° at 69Hz, implying that this speaker does require an amplifier that is not upset by a low effective impedance."
This statement "There is also a combination of 4 ohms and –64° at 69Hz" means the amp could see an EPDR load of down to 2ohms!!!!!!! And it stays at 3ohms for the rest of the bass and upper bass!!!
Cheers George