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 #139477  by Searing75
 Sun Jun 01, 2014 7:02 am
How many speakers in each cab? Assuming they are all 8 ohm?
 #139503  by ccw3432
 Sun Jun 01, 2014 8:31 pm
You'll just need to calculate the ohms accordingly in the same manner as if you made the connections within a speaker box. If you used one channel on the Mac and went pos to pos and neg to neg at the terminals for your 2 separate speaker wires it would be the same as wiring your cabs together in parallel. Another way to do it that I have also tried is to split my SMS signal and ran in into both channels of my MC250 and then out to a separate speaker for the left and right channels. Depending on what you're looking to do, you could have it pre-wired to easily add a second cab when needed on the extra channel. In this case the channels would be independent of each other.
 #139510  by hippieguy1954
 Mon Jun 02, 2014 6:07 am
I would hook up one cab to the 8 ohm tap and one cab to the 4 ohm tap respectively. Both negatives to common ground.
 #139530  by hippieguy1954
 Mon Jun 02, 2014 3:33 pm
I don't see any reason why it would damage the amp. It's designed to accommodate different impedances. The manual does not warn to use only one speaker impedance output at a time. I think they would specify that if it was a problem. You can call them too.

Here is the manual: http://www.berners.ch/McIntosh/Downloads/MC100_own.pdf

Personally, I like to flirt with the McIntoshes limits and would connect them both the the 4 ohm (or a 2ohm if it had one) just for fun :smile:
 #139533  by mkaufman
 Mon Jun 02, 2014 5:59 pm
Sorry if I'm being dense, but I'm still confused. The manual shows using two different MC100's: one for the left channel and one for the right channel. It doesn't show an example of connecting two separate speakers (or cabs) simultaneously (maybe because it's not a stereo unit?).

I fully understand that one can connect a speaker cab with two speakers to the MC100, but that only requires one connection to the MC100. You're approach uses two simultaneous connections with different ohms to the MC100, and that's where I'm uncertain.

I can see wiring the two cabs in series and connecting them to a single MC100 connection (ie: MC100 -> cab1 -> cab2), but is simultaneously connecting two cabs to two separate ohm connections ok?

mk
 #139535  by ccw3432
 Mon Jun 02, 2014 6:13 pm
Oh, mc100. Obviously disregard my stereo suggestions above. I was thinking 2100. I have no idea about using two different ohm connections on one channel.
 #139537  by hippieguy1954
 Mon Jun 02, 2014 7:47 pm
Yes, the diagram in the manual shows two amps. That is for stereo operation and as you say, your Mc100 is not stereo. It is one channel mono only, but as I stated above, the manual does not warn or say not to use more than one impedance simultaneously. The manual does mention that mismatching does not compromise any built in protection and is no problem except for distortion at high volumes.

Yes, wiring the two cabs in series and connecting them to a single MC100 connection (ie: MC100 -> cab1 -> cab2) will work, no problem. You would have about 6 ohms all together and could come right off the 4 ohm tap with no worries. I would certainly do it this way if you are concerned about using simultaneous impedances.