Powering a center channel with a two channel amp

@vacerator posted:

Huh, well, I guess I’ll have to talk with my McIntosh guy about that.  Everything I read on the web suggested or said that center channel audio couldn’t be amplified correctly with a left or right channel from the amp.  My take off was that a left channel would pull left channel audio and not the full center audio sound.  I have absolutely no education in this area, as to how the amp actually amplifies sound.  If an amplifier purely amplifies sound, which is what I originally thought, then what Jeffbig should work.  Not sure how muvluv’s set up would work correctly, I guess if you ran a 2 to 4 rca?

I got an email back from Mike, from Audio Classics, and he iterated the proper set up being parallel and mono.

I’m not sure why you posted this thread on Agon. You should just follow the advice you got before posting your thread. Wrong advice, IMO, but you should just follow your gut.  

You didn’t mention the speakers you are using. The center ch speaker is probably considered the most important, followed by the L&R ch speakers.

FWIW, IMO, the Marantz SR6015 digital processor is more than likely the weak link in your multichannel system. The  Marantz SR6015 would be considered mid-fi, not high end. 

Jmho, it hardly does justice to a McIntosh 352 power amplifier.

I see the SR6015 has been discontinued. Note, the SR6015 was made in Vietnam. 

You might want to step up to a Marantz Cinema 40. It’s made in Japan. IMO, this AV receiver would be considered high-end. 

Huh, well, I guess I’ll have to talk with my McIntosh guy about that.  Everything I read on the web suggested or said that center channel audio couldn’t be amplified correctly with a left or right channel from the amp.

@vacerator 

I’ve been involved in cinema sound long before home theater existed and my experience is that’s not correct.  There’s no such thing as a Left, Center or Surround amplifier.  They are all just amps subject to the same ratings and limitations of any other amplifier.  The labels of Left and Right or Center are just convenience.   You might as well number the amps 1, 2, 3, etc.  instead.  

In cinemas, before Dolby Digital, we would use 2 stereo amps, one channel each for Left, Center, Right and Surround.  Yep, we often used a single amp for the entire surround speakers with judicious parallel/serialization.  Back then the Surround channel was 1, not 4 or whatever it is now with Atmos. 

So, yes, you may use 1 channel of a stereo amp for your center channel so long as the amp and speaker are otherwise a good match for impedance, sensitivity, power, etc. 

It’s sad to waste an amp though so not uncommon to see it bridged if the amp supports it.  Note that minimum impedance is usually higher for amps when bridged.   Otherwise, if your center supports bi-amping it’s another option for fully using a stereo amp. 

Since the invention of HT however the idea of a 3-channel amp to enhance a stereo amp has become popular as well... the idea being that you can power 2 surround channels plus the center.  Again, there’s absolutely no difference in the electronics.  It’s just a 3 channel amplifier.  

Of course, what you should be doing is using 7 monoblocks.... Hahahaha.  Just kidding, but it would work too. :) 

Having said all of that, the input to whatever amp is connected to your center speaker should come from your HT receiver/processor’s center out.  Not any other source.  There have been a number of mini appliances in the past to create a center channel from L and R outputs... but I can’t think of a reason to use them in the 21st century unless you are trying to recreate 3 channel stereo from the early recording days. 

Hey Jea48,

I’m curious what you mean, wrong advice?

One thing I never do is fallow feelings or gut.  I’m looking for correct information.

in reference to the 6015, yep, one thing at a time.  I do have an INNUOS ZENMINI MK3 MUSIC SERVER-STREAMER and a INNOUS POWER SUPPLY, and Kaleidescape for movies.

B&W CM10 LR & matching B&W CM Center 2.  I’m currently testing a HTM71 S3, and haven’t been able to make a decision between the two.  The vocals are definitely more pronounced on the new center, but not sure about blending in with my LR.  I’m waiting for my new amp to make that decision.

Thanks for that Erik!!

So, what Muvluv said was correct then.  You can use the left for the tweeter and mid, and right for the bass.  Currently, I have a bi wire cord, so I’ll have to change that.  I like this idea better than bridging, mainly for the reason of impedance.  I don’t even know how many cords I’ve changed out now, because of various changes 🙃

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+1 @jea48 and @muvluv

@vacerator 

You are over thinking things.  Your Marantz has preamp RCA outputs for each channel.  Left, Right, Center, and surround channels RCA connections. 

Connect the:

• Marantz left preamp output RCA's to the left input on the MC352 amp #1,
• the Marantz right preamp output RCA's to the right input on the MC352 amp #1,
• the Marantz center preamp output RCA's to the left input on the MC352 amp #2

That will leave the right input RCA's on the MC352 #2 amp connected to nothing, which is fine.  Then connect the speaker cables to the MC352 connections to the approperiate speakers.  You may need to go into the Marantz setup menus and tell it you are using the off board amps for the front 3 channels (L/C/R).  

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As previously posted recommendations, I am in agreement. 

just simply look at your back panel and all is there. at the most, you may just have to use 1 channel of MC352 and leave the other unused. I am doing in my home theater setup too.