Question Stereo amp to subwoofer connection options

norliss

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My subwoofer is currently connected to the sub-out connector of the AV amp as is pretty standard, but I'm in the process of moving back to a stereo amp. I understand that it's considered better to use a high-level connection to connect to the speaker terminals and I still have the required cable supplied with the sub.

However, in the manual of my prospective amp it clearly states "Do not connect your active subwoofer to the SPEAKERS L/R CH terminal. Connect it to the PRE OUT jacks." Any idea why this might be the case?

Assuming I do go via the pre-out jacks, would it make much difference if I used a stereo -> mono phono adapter and stuck with a single mono run or would I see much benefit in using two separate cables for each channel?
 
Apparently your anonymous subwoofer has line level inputs and no speaker level inputs. This is why the manual warns you - to prevent your blowing up your subwoofer but whacking way too much current through it.

To answer the other question you really will need to identify the subwoofer as what's best depends on what you have. It will also be possible to help you with other connectivity options. Apparently your unidentified stereo amplifier has no bass management, so you will also need to deal with balancing the subwoofer to the speakers.

A stereo to mono phono adapter is normally a bad idea - unless of course you're looking for an excuse to buy new equipment. Generally you want a summing amplifier or a transformer. Example: Monacor SMC-1 - Stereo to Mono Audio Converter (RCA)
 
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The subwoofer is a BK XLS300/PR and the amp will be the Yamaha A-S1100. I thought I was going to use the High Level Input Speakon cable supplied with the sub, but the A-S1100 manual seems to warn against this for some reason. BK said it might be either because the amp is Class D (it isn't) or a bridged design.

In any case, if I do use the pre-out jacks instead, I'm wondering if I could use a 2 phono -> 1 phono cable and make use of the existing, single phono subwoofer cable into the sub, or would I be better off using a pair of phono cables from the amp's pre-outs to the two phono connections on the sub?
 
The BK's use a neutrik connection, which have a shared earth, not always liked by source equipment. You could ask Yamaha if your amp supports the connector, but without confirmation I'd be wary, since the A-S1100 has a balanced power amp and the manual clearly says not to (p17).

I suggest purchasing a stereo RCA cable, or if you can't replace the existing mono cable a proper adapter (see my previous post), but caution against a 2 phono -> 1 phono cable unless your fire insurance covers arson.

Your BK does not have a high pass filter out, so will need careful balancing.
 
Hi Mark - thanks for your replies. I've fired off a question to Yamaha but if I don't hear back from them before I get the amp, I'll err on the side of caution and avoid the high level connection.

I was planning to buy a cable like this then make use of the existing, single phono subwoofer cable. Not sure what you mean about arson?! :confused:
 
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I was planning to buy a cable like this then make use of the existing, single phono subwoofer cable. Not sure what you mean about arson?! :confused:
I mean that the chances that your using that cable will cause a fire are not negligible, and that your insurance will likely determine that you burnt down the house deliberately and refuse to reimburse you.

Destruction of the amplifier can be taken as a certainty.
 
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Really?! A REL setup guide suggests this: why is it likely to cause destruction to the amplifier?
 
Because that cable short circuits the outputs of the amplifier. Amplifiers don't like to be shorted out and react quite violently to such actions (some do have protection circuits to prevent destruction). You must have misunderstood the REL setup guide (do you have a link?).
 
Second page, first paragraph after bullet points:

Edit: it's a pdf and I'm having trouble doing this on the phone. I'll do it on the computer in a short while.
 
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I hadn't noticed your update, but there's not really much more to suggest - at least not before you get a response from Yamaha.
 
I've still not heard back from Yamaha but will opt for separate subwoofer cables to be on the safe side.
 
Norliss Did you ever figure out what cable to use to connect with REL sub to
Yamaha AS1100? Why not just use one side of the stereo RCA cable? from amp to sub
 
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