How best to connect my sub to amp?

[ciderman9000000]

Hi,

I'm in the process of upgrading my hifi. I have a NAD C326BEE stereo amp with Mordaunt Short 902i bookshelf speakers. It sounds good, but wanting some extra bass I took a look in Cash Converters today and found myself a Cambridge Audio SX120 active sub woofer for £49.99.

I haven't any cables for it yet, and am a little confused as to how best to set it up. The amp has single Sub1 and Sub2 outputs and the sub just two RCA inputs. The sub's manual suggests two different connection options (see pics below), but does it make any difference which I use? Since the amp has dedicated sub output ports, am I better using the 1x phono cable as per the diagram suggestion for AV equipment, or is it necessary that I use the amp's pre-out ports and a 2x phono cable as suggested for use on 2-channel systems?

Any help much appreciated, thanks.

[struth]

I think the white one on the sub is mono connector. the amp may run 2 active subs i think. thats how i see it.

[Macca]

use both sub out sockets on the amp, connect one to white socket on the sub, one to red. Then spend several days getting the position of the sub and the levels just right.


You'd really be better off buying bigger speakers, but it should be possible to get it to work well, it just takes a lot of trial and error.

[struth]

by looks of the amp out they are mono outputs as they are not colour coded.

[Macca]

Doesn't matter, it will still work fine.

[walpurgis]

That's what I thought. I dare say both can be connected to the sub L/R inputs, which are summed to mono anyway.

[Stryder5]

As the sub output of the amp is summed L&R there is no benefit of using 2 sub RCA's, extra cost for no benefit.

You have pre-outs in the amp, but if you use these you loose the power side of the amplifier, to the main speakers, so you would only feed the sub.

[struth]

Doesn't matter, it will still work fine.

it might cause phase issues if you connect both

[ciderman9000000]

As the sub output of the amp is summed L&R there is no benefit of using 2 sub RCA's, extra cost for no benefit.

You have pre-outs in the amp, but if you use these you loose the power side of the amplifier, to the main speakers, so you would only feed the sub.

So you're saying that the correct solution is a single phono lead from Sub1 to the white input on the sub, yes? As per the manual's AV connection suggestion.

My understanding of pre-out is limited at best, but my intuition was that connecting anything there might compromise power to the main speakers. But if so then why does the connection diagram in the sub's manual suggest such a setup?

[Stryder5]

So you're saying that the correct solution is a single phono lead from Sub1 to the white input on the sub, yes? As per the manual's AV connection suggestion.

My understanding of pre-out is limited at best, but my intuition was that connecting anything there might compromise power to the main speakers. But if so then why does the connection diagram in the sub's manual suggest such a setup?

Point 1. Sub 1 or 2 will work, so the answers yes.

Point 2. Some amplifiers have pre outs to feed a seperate power amp. The internal power amp is still connected. That is what's suggested in the second diagram. On the NAD there is a jumper that feeds the pre amp to the internal power amp but by using this you disconnect the power amp therefore the main speakers.

Hope that makes sense.

Gary