Two pairs of speakers to McIntosh 2200 ?

Hi there, everyone. I have a McIntosh 2200 amp arriving soon. I would like to connect two pairs of speakers to this amp in parallel, at least temporarily. One pair is 4 ohms and the other 8 ohms.

The 2200 has the autoformer, so there's separate connections for each set of impedances - 1, 2, 4, 8 - and you get 200 watts per side regardless of the impedance.

Should I connect one pair of speakers to the 8 ohm terminals and the other to the 4, or should I connect everything to just one set of terminals, like the 2 ohm set (the combined impedance is 2.6, correct?)

Please help me out. Thanks.

...the only "2200" anything I can find @ the McIntosh site is a pre-amp...and there is no power amp rated @200wpc...at least in their current models...

I did find a picture at one site for a very atypical MC-2200 200wpc solid state unit...aluminum faceplate sans meters...nothing else during my search...

Product divided by sum does ring a bell...

jimHJJ(...just wonderin' about the unit...)

I'd probably go with either the 2 or 4 ohm position. Actually, I would call Mac and see what they recommend here.

The math, for those who don't know, to determine the impedance of two speakers in parallel is as follows:

Where S1 = impedance of speaker 1 and S2 = impedance of speaker 2

(S1 TIMES S2) over (S1 PLUS S2), or
((8 * 4) / (8 + 4)), or
(32 / 12), or 2.667 ohms.


P.S... the math for connecting two speakers in series is simply S1 PLUS S2, or 12 here.

Yes, this is in fact the MC-2200, 200wpc w/ the silver faceplate from the late 70's. I guess I'll either try both on the lower impedance terminals or contact McIntosh. Thanks.