How do I use computer speakers with an old amp?

August 7, 2009 8:03 AM

How do I use computer speakers in a vintage amp?

Posting this anonymously so I don't get mocked by certain people for being clueless, which I am.

I recently got my hands on a decent old amp but at the moment, I just can't afford speakers. I need something to use to get me through the next couple of months, till I can afford a decent set. The only thing I have at the moment is some computer speakers- they're actually pretty nice ones, with a decent subwoofer. Obviously NOT what I should be using but again, this would be a temporary fix.

The problem is is that the amp has the old spring-loaded connectors that require the bare speaker wire, obviously. The speakers go into the subwoofer which then is meant to connect with a jack- the jack doesn't fit into any of the inputs on the amp (and I'm not sure that would work anyway). So the question is, can I strip off the jack somehow, or is there a connector of some kind I can get that would accept the jack on one end and be bare wire on the other? If I manage to disconnect the jack, is there actually speaker wire in there?

I have searched and searched various audiophile forums for an answer but I have a feeling this is way too basic a question that nobody on there would bother asking (or answering).

Thanks in advance...

posted by anonymous to technology (6 answers total)

The computer speakers probably have an amp built in. The jack on their connectors is meant to plug into a headphone or line-out jack. That is, they're meant to take an unamplified signal. Don't try to plug that into the amplified signal on the back of your amp. I recommend just using the computer speakers by themselves until you can get decent speakers that will use your amp.
posted by reegmo at 8:21 AM on August 7, 2009

I am not an audio expert. I am not your audio expert. But I see a few problems with this. First, the amp expects a certain load from the speakers attached (probably 4, 8, or 16 ohms). Attaching something that doesn't provide this load could cause problems (a blown fuse, or worse). Second, your computer speakers have an integrated amplifier. Feeding them a signal meant for unpowered speakers is likely to cause problems (a blown amp). Finally, the wire running from the 1/8" connector to the subwoofer is likely of very light gauge (high resistance), and might get hot when fed the signal from the amp (it might melt the insulation and/or catch fire).

This is probably a bad idea. It's unclear why you can't just use the computer speakers without the amp. Or, if the amp has a headphone jack, you should plug them in there.
posted by uncleozzy at 8:21 AM on August 7, 2009

No, you can't directly use those speakers with your amp, as they are powered speakers with an amplifier built into the subwoofer. If the amp has a line out you could connect the computer speakers with that. But do not connect the speaker outputs to powered speakers.

If your vintage amp is vacuum tube gear and you are running without speakers make sure the selector switch is turned to a speaker off or headphone setting. Tube amplifiers do not want to be run without a load.

If you check your local thrift stores frequently you'll eventually find some good speakers for $20-30/pair. Older and heavy are what you're looking for. If they feel light for their size you don't want them. Pull the speaker covers off and make sure the surrounds of the speakers are intact and not brittle. Foam surrounds, especially on woofers, of a certain vintage are likely to have dry rot, and will crack or crumble to your touch. If you have a way to test them in store, do so, because very often they won't let you return electronics, and it's common to find speakers with blown tweeters from people cranking them too high, especially with an underpowered amp that clips.

A partial list of makes that would catch my eye: Advent, Avid, KOSS, older Pioneer and Sony, Marantz (definitely check the surrounds on Marantz). But there are lots out there that would serve you well.

If all that sounds like too much work then let the amp sit on the shelf until you can save up enough to buy speakers.

A final note on nomenclature, at least in the US: an amplifier is just that, an amplifier. It might have a volume control and maybe a selector switch for inputs. A receiver is significantly more common. In addition to the amplifier a receiver will have AM/FM tuners, various input and output options, likely a tape monitor switch for recording to tape, tone and balance controls, often other tone switches like loudness and low and high cuts, outputs for multiple pairs of speakers and a speaker selector switch, and so on.
posted by 6550 at 9:10 AM on August 7, 2009

Many years ago when I was first playing guitar, I bought a used Marshall amp from a friend. I didn't have a speaker cabinet for it, but I figured it would be OK to run it through the little combo amp I'd been using for practice. Tried to play a chord and POP-- just silence and a puff of white smoke. I blew the transformer in the Marshall, which is not a cheap repair. It always made a lot of noise after that, I ended up selling it for a lot less than I'd paid.

Go to a thrift store and pick up a cheap pair of speakers to tide you over until you can afford better ones. Make sure the ohm ratings match, as uncleozzy suggests.
posted by InfidelZombie at 9:22 AM on August 7, 2009

Striping the wires on powered computer speakers and wiring them to your vintage amp is likely to destroy the computer speakers, and possibly damage the amp. Use the line-out or headphone out of the amp, and connect it to the line-in of the powered speakers. If your amp had a pre-amp output, that would be the thing to use.

Save $50-$100 when you can, and buy real speakers. You could get new Energy C-50's for $80, or used KLH speakers for $50 from audiogon.
posted by paulg at 9:31 AM on August 7, 2009

As other posters have mentioned, the computer speakers most likely have their own amplifier.

If you're scrounging old speakers, note rotted woofer surrounds can be repaired at home cheaply and fairly easily.
posted by zombiedance at 10:35 AM on August 7, 2009