I have a topping TP-30 USB DAC. http://www.parts-express.com/pe/showdetl.cfm?Partnumber=310-312 It's worked fine for the 6 months ive had it. I notice now that the volume control nob makes some static when I turn it up. I figure there's some dust in there or something. Would DeOxit be a good solution?
They also make a fader luber that cleans and lubricates....
By the way...how do you like the sound of this unit. I was looking to get the TP-31 which adds a digi in...was going to use the unit as a headphone amp for the digi out on my sound card..
I like the TP30 alot, it is my first ever foray into these types of units, and I would say that as a headphone amp, it is leaps and bounds above whatever I have had in the past. I have sennheiser HD280's, and a cheapish set of bookshelf speakers which I use with the amp. It looks and feels like a pretty expensive unit, alas it is the most expensive playback device I have ever owned. Definitely plenty of power. I don't know if others would agree with me, but I would describe the sound as transparent. Probably because I have only every listened thru cheap headphones on my computer's headphone out, and 20 dollar logitech computer speakers. The high frequencies sound natural, the bass is crisp and not overpowering or muddy. The only thing I wish this amp had was some EQ controls.