If this is for a cabinet I suggest finding one with the added dual stereo headphone out connectors and volume control (Blaze DC VGA Adapater, or GameMadness VGA adapter). This will let you regulate the input volume going into your amp. All the other cheap ones I've tried have the headphone output level much to high to drive an amp (and you end up getting lots of distortion).
I just checked ebay and see lots of the cheap ones ~$10, but none with the volume control. Not sure if Level Six has such a model.