Not only going into the pc, also going out your pc. Apogee developed the UV22 filter, which purpose is to enhance your master path by creating a pristine conversion between whatever goes in or out.You have to take notion that most soundcard Bitrates dont really provide what they claim to do, like some cards have 24bit in spec, but actually perform at 19bit, which affects the quality. It increases your noisefloor, snr which gives more headroom and prevents loss of bits or creates a stationary low voltage for analogue output. So eventually, you truely get 24 bit and bladiebla dB snr. The PT occasion you refer too is the ad8000/da8000, which is a 8 chnl converter but is not neccesarly a PT attribute. The digital Yamaha desks, like db8 also came with Apogee bus converters, but not standard. Both the PT and DB8 included the renewed and improved UV22hr to adapt to higher resolution standards and Steinberg products like wavelab and Nuendo now come with UV22 filters, software matic algorhytmic copies of the hardware converters ( but use only on 24bit cards and I've also heard engineers saying to not use em at during rendering ). So, if you looking for THE pristine line/mic/instrument pre amp, try the mini-me, its the cheapest so far but the quality is till the same of the AD8000, if not better.
On the other hand, there's the MOTU192 which I doubt will do less then a AD8000 when comparing the prices. I wish I could say the same thing about the quality difference but that becomes a really expensive experiment hehe