Using a Mac Stereo Amp for Mono Operation?

[70sMac]

Originally Posted by damacman

Your MC300 would best be used to power the Left and Right speakers in a 5.1 system. Configuring it mono would provide 600W into a single speaker - a tad more than necessary and then you're left without its use as your primary amplifier for the Left and Right speakers - both for 5.1 and 2ch listening.

Adding an amp like the 7100 is an economical solution to the problem you have. Its rated at 100wpc into 8 Ohms stereo or 300W when bridged mono into an 8 Ohm speaker. Using it in conjunction with your MC300 gets you 300W into L, C, and R speakers.

Now, McIntosh also offered a 6ch version of this amp - The MC7106. One can also operate it into 3ch with an output of 300wpc x 3 - adding 300W to C, LS, and RS channels. When used with your MC300, you now have 300W at each of five channels.

DaMacMan..... Although I fully intend on giving both of your latest posts the attention they clearly deserve, I assure you that I was predicating my last post (to you) on using the MC300 in mono mode (as suggested). On the other hand, using the MC300 to drive our 802N fronts -- as it has done since we purchased all three units -- is fine with us. This amp drives those speakers beautifully, to our ears, so no argument there.

Thinking back to my AC Theory courses -- and all of those complex impedance (X sub L) calculations we had drilled into our heads -- I might beg to differ with you about what those MC300 output taps can deliver to an 8-ohm input impedance, when in mono mode, but I suppose that's not something we should get into, assuming that the MC300 is back to being used as a stereo amplifier...

I just found an old ad for an MC7100 that was once for sale and, sure enough, it is specified to deliver 300 Watts into an 8-ohm input impedance -- when in "monophonic" (bridged) mode. Therefore, it should be fine to drive an 8-ohm center speaker -- which is what we're looking for right now -- and, as you pointed out, that means that all three of our "fronts" in a 5.1 surround setup will be capable of 300W max.

Obviously, that's one way to handle the surround fronts, so thank you for the great information. The MC7106 that you mentioned seems to be another great solution, but I can't find one that's for sale (as I type this).