Pre amp to amp connection

[Data Link]

Hello, this is my first post and I am a low voltage contractor, primarily data, video and voice structured cabling. I came across a commercial audio job, 18 speaker (non dual voice coils) with 9 volume controls (each volume controls 2 speaker).

I am using an 8 channel amp and a 12 channel amp, all speakers are wired in a homerun fashion (each channel in the amp has a +/- going to each volume control, and then each volume control has a +/- going to each speaker). This may sound like a waste of speaker wire, but it has been pulled and connected.

The problem is that the client wants mono played out of each speaker.

The plan I have is to use the current NAD 7020i amp/receiver/tuner (I know, old but good) that he has and use the pre-out to connect to the 2 amps. In essence, I am only using the NAD as a receiver/tuner (bypassing the amps) and using line out to the real amps. Problem is, I need to split the stereo sound into mono to both amps.

I've been told that I can use a stereo to mono cable from the NAD line out, and then split the mono signal into 2 using a y cable to the "L" channel of each amp. The 2 amps have linking capabilities to share the same source with all channels.

Does anyone see a problem with this set up? Thanks for your consideration.

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I read my post and want to clarify:

1. The linking capability in the amps apply to each amp, not between the amps. Said another way, in the 12 channel amp, channel 1 will be shared with the next 11 channels on that amp. In the 8 channel amp, channel 1 will be chared with the next 7 channels. There is no link between the 12 channel amp and the 8 channel amp, thus the need to split the mono output from the NAD to the input on the amps separately. Also, these are stereo amps, not mono.

[rbinck]

What are the amps? The reason I ask is the Niles multichannel amps have the ability to set switches for what you want to do as well as they have an output to cascade multiple amps.

In any case there would not be a problem using a Y cable to connect the 2 stereo outputs together on the NAD line outs and then other Y cables to get to the four connections you need for the 2 amps.

[Data Link]

rbinck - I really appreciate your prompt response.

The amps are Knoll ma1250 and Knoll ma850. Neither have outs to cascade from amp to amp.

I have 1 ignorant question(s):

So, out of the NAD pre out is a 2 male to 1 female Y connector, and then a 1 male to 2 female y connector, and then an individual RCA male to male connector from the Y to the "L" input of 1 amp, and then an individual RCA male to male connector from the Y to the "L" input of the 2nd amp? This will produce mono sound to all speakers? One other note, the NAD has a "mono" button, but not sure if it applies to tuner only, or to all inputs.

[rbinck]

Originally Posted by Data Link

rbinck - I really appreciate your prompt response.

The amps are Knoll ma1250 and Knoll ma850. Neither have outs to cascade from amp to amp.

I have 1 ignorant question(s):

So, out of the NAD pre out is a 2 male to 1 female Y connector, and then a 1 male to 2 female y connector, and then an individual RCA male to male connector from the Y to the "L" input of 1 amp, and then an individual RCA male to male connector from the Y to the "L" input of the 2nd amp? This will produce mono sound to all speakers? One other note, the NAD has a "mono" button, but not sure if it applies to tuner only, or to all inputs.

The mono button should apply to all inputs. If it does then the connection would be much easier by using two Y connectors. Otherwise the hookup you describes should do the trick.

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Thanks again. I will try the mono button first, then use the latter as a back up plan. You guys are fast!