guitar via USB to iMac

Is there anyone who can tell me whether a particular cable suitable for feeding a guitar into Garageband on an iMac? The cable in question is this one:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item...

My son bought it, but when he plugs it into his guitar (an electroacoustic) and plugs the other end into the USB socket on our iMac, it does not seem to be recognised by the Mac as a device. In the Sound menu in System Preferences, it does not appear as an input device. The indicator light on the USB end of the cable does not illuminate. Perhaps the cable is simply faulty, but before giving the vendor a hard time I wanted to check if I should be doing something else in order to make it work.

The listing seems to claim that it should just work on a plug and play basis, as the cable has a built-in driver and signal boost. Am I missing something?

That looks unlikely that it would work. Are you able to try it with a PC?
I see it says mac compatible. It should work then.

Edited by stniuk (Fri 03-Feb-12 13:44:02)

Looks from the description as though it should work, you probably have a duff one. But what was wrong with plugging the guitar directly into the Mac audio line input? The cable would be a lot cheaper.

I know these cables exist and you can buy them on Amazon as well, but I think they are made for standard electric guitars rather than electroacoustic...
To record, I'd suggest either miking up the guitar, or using a decent external sound card...

In reply to a post by qjh1:

Looks from the description as though it should work, you probably have a duff one. But what was wrong with plugging the guitar directly into the Mac audio line input? The cable would be a lot cheaper.

The merchant readily agreed to send me a replacement, without even wanting me to return the first one. I can't help thinking that he probably knew that these cables are dodgy. So, let's see if the new cable works, when it arrives.

I don't know why my son did not use the audio line input. He might not necessarily have known that this was possible, or perhaps he did not have a suitable cable. Based on a very quick Google, I see that using the audio line input is apparently not great quality, so perhaps he hoped USB would be better.

In reply to a post by metalhead41:

I know these cables exist and you can buy them on Amazon as well, but I think they are made for standard electric guitars rather than electroacoustic...
To record, I'd suggest either miking up the guitar, or using a decent external sound card...

The guitar already has a Fishman Presys pickup. When you suggest miking up the guitar, do you mean something other than this?

Miking up would mean placing a microphone near to the guitar and plug that into your soundcard instead...
Silly question, but you did turn the preamp on the pickup on didn't you?

Thanks. Unfortunately, the only microphone he has is the internal mike on the iMac and I suppose there is also the USB headset for the computer. I imagine these are not going to be good quality.

I assume my son turned on the preamp. I just went and had a look, and it does not seem to have an on switch; I presume you just turn the volume to 0 to switch off.

I just checked the manual and to turn it on you just plug in the cable.

Not cheap but one of the best names:
Apogee Jam