I've looked on and off for a high quality 48 volt power supply for my Horizon without much success yet. If anyone finds something, please let me know.
On a somewhat related note, it seems that my setup sounds better late at night (sometimes a lot better) so I suspect that the power could use a bit of cleaning up. This has lead me to look into power conditioners. Either DIY or purchase one like this: http://www.amazon.com/Furman-AC-215A-Conditioner-Auto-Resetting-Protection/dp/B003PJ6NPO/ref=sr_1_5?s=electronics&ie=UTF8&qid=1360038284&sr=1-5&keywords=furman+conditioner
A DIY power conditioner called the Felix: http://www.audiocircle.com/index.php?topic=50284.0
It's interesting that in the first post in the Audiocircle thread, the poster mentions that using the power conditioner, his Squeezebox sounds better with the stock switching power supply than a linear power supply with or without the power conditioner. Anyone using a power conditioner? Hope I'm not sidetracking this thread too much.