Can I successfully run a sub using one rca cable from the hifi?

My pre amp has two sets of outputs. One pair powers my monoblocs. The hifi is temporarily situated in the lounge. In the lounge is a BK sub, which my AV amp is connected to using a hi level speakon connector. What I’d like to do is to also run one rca cable from the hifi to the rca input on the sub marked mono.

I’ve read that i should run two rcas from the hifi to the sub. I dont want to do that and would prefer to only use one. Will one work? Would one sound ok?

No. It’ll be rubbish, because you’ll only be getting the bass out of one channel of your system. So it’ll sound completely odd if bass comes out the non subwoofer channel.

Cant you just get a slimmer pair of RCA’s, I can’t believe 3-4mm of wire width is going to make or break anything.

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Thanks. Two cabies it is then.

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Yes there is a way to have one lead for the run and get both channels and that is to fit a Y connector on the second pair of outputs. Then continue the main run in a single double signalled cable. How long will the run be and what colour cable? I have 2 x 3m RCA to RCA cables in Black so you could have up to 6m single run. I’m in the middle of a clear out have several crates of connectors -Happy the go to someone who’s using them
If this is suitable to you I can send them free gratis just PM me your details

That second cable definitely doesn’t look like it has any quantum in it


Just to clarify, what sort of fuses will you be using?
Asking for a friend.


I don’t think that this is a particularly good idea through.

While splitting an input signal into two presents no electrical issue, what you’re essentially doing here is bonding two different outputs into one, which means two different voltage sources become connected. It’s not a particularly good idea to do it this way, and could damage the amplifier.

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If I have given unsafe advice apologies to the OP but it’s not a risk that I knew about.

Those wires are normally for summing up an input from a mono to dual.

In the same way you wouldn’t connect your loudspeaker outputs together, you shouldn’t do it with outputs, because they’re voltage sources.

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Really depends on your pre-amp or receiver outputs, e.g.

that works when a preamp has a mono LFE output, but it sounds like OP is using a standard stereo preamp.


Yeah, its a standard stereo output from the pre. I don’t want to risk damaging it. Thank you for the kind offer regardless. Two foo cables look like the way to go.

Just run one cable to one sub. It will be okay.

It might even be nice.


You can’t just connect the outputs together as pointed out. You need to have some kind of summing network or processing.

Something like this:

I’d say just connect to one channel and see if it works. Most low bass is mono-ed anyway.

Edit: or just run two cables if the sub has two inputs and performs its own summing.

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Apologies again for my poor advice

Just don’t want anything to get damaged.

Ah, good old one channel bass… that’s what vinyl is for isn’t it!

In fact it’s not even mono bass, it’s half of mono bass.

Then run two cables and do it right :slight_smile:

Half of mono bass is just mono bass. :man_shrugging:

A bit like what’s 2x :infinity:

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