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Two amps to power 7.1 speakers?

I have  2 McIntosh amps, a MC7205 (5 Chan) and a MC58(8 Chan)   I have 2 Polk Audio RTi A9s a Polk audio RTi A6 center 2 Polk Audio TSi 500s surround and would like to add 2 TSi 200s surrounds.  My Preamp is a McIntosh MX-136  7.1.   Can I run the A9s, A6 and 500s from the MC 7205 and use the MC58, bridged, to get 100w/ch from the MC58 to run the two 200’s.  Running the interconnects from the MX 136 surround ports to the MC 58?  I don’t want to ruin any of the equipment, so if it’s something that may cause harm, I won’t do it and sell the MC 58.
cody57
7 responses Add your response
oldhvymec
5,101 posts
 
Yes, and have a few rails left over. You need to power 7 speakers.
You, have 13 rails before the bridge, 11 AFTER.
  
There is room for bi amping the RTi A9s too boot.
Use two of the channels on the MC58, to power the tops, two of the 7205 for the bottom section.

Regards
imhififan's avatar
imhififan
2,205 posts
 
My suggestion is bridge all channels of the MC58 to make it a 4 channel amp to power all 4 surround speakers.
Using 4 of the channels from MC7205 to vertical bi-amp RTi A9s and one remaining channel power the RTi A6 center.

cody57 OP
23 posts
 
The MC 58 is only 30w/ch and 100w/ch bridged.  I’m not sure how to vertical bi-amp.  Too bad the MC7205 can’t be bridged.  I spoke with a technician at McIntosh about bi-amping the MC58 with the MC7205 to help power the A9’s because they’re known for drinking power and he didn’t seem to recommend any bi-amping. I don’t know if vertical bi-amping is different or if he misunderstood what I was trying to do.  I’d rather have the 7205 power the tower TSi 500s I’m using as back surrounds as they put out 120w/ch conservatively and the 58 only 100.
imhififan's avatar
imhififan
2,205 posts
 
Running the interconnects from the MX 136 surround ports to the MC 58?
Connect all 4 surround channel via rca interconnects from the MX 136 surround ports to the MC 58 input 1,3,5 and 7, set all 4 pairs of amp to bridged.
For vertical bi-amp the RTi A9s you can use "Y" rca interconnect cables.
cody57 OP
23 posts
 
I like that idea!! This way I’m not ‘wasting’ the mc58, I really hate to give up, this utilizes both amps and boosts the power to the RTi A9’s.  Now, I would connect the speaker cables from the amp with more power to the the (3) 7” woofers, correct? I guess the tech @ McIntosh was saying the 7205 had enough power to drive the A9’s “beatifly.”  But more power YES!!  Would that increase the power to 220w/ch?  Thanks you guys for the help!
cody57 OP
23 posts
 
You had me, then ya lost me. I thought I was to run the pos and neg speaker cable from the bridged MC58 to the pos and neg on the HF speaker ports and the pos and neg from the mc7205 to the pos and neg LF ports. Why would I need a ‘Y’ interconnect?
imhififan's avatar
imhififan
2,205 posts
 
Since you're using two amplifier channels for each speaker, the "Y" rca interconnect cables are used to connect the MX-136 L and R output to amplifier's inputs.
BTW, if you want to use MC58 for HF speaker ports and MC7205 for LF ports, it's horizontal bi-amping. 

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