Stable 12V DC power supply

I read somewhere that one of the few available tweaks for a ClearAudio Concept is to use a stable 12V DC power supply (i.e. a battery) instead of the provided wall-wart.

I thought I had come up with a great solution: the XTPower 10,000mAh external laptop battery. Among many options it includes a 12V DC output rated to 2A. It costs $38 - considerably less than power supplies targeted at the audiophile market.

Here's my problem: Since the device is designed to re-charge laptops and cell phones it switches itself off if the current drain is below some threshold. The motor in the turntable is rated at 480mA, but probably draws considerably less when up to speed.

So about 2 minutes in to "Well, You Needn't" and the turntable winds down to a halt :(.

Anyone know if there's a way to "trick" the device into thinking the current draw is higher, or raise the current draw, or over-ride the settings. Otherwise it's back to the drawing board - any suggestions on a simple (and not too ugly) way to get a good 12V DC supply? Are any available wall-warts of better quality?

Thanks for any suggestions.