Why does Computers - Amp - Speakers sound better?

Some basic questions:

1)Is the cartridge new, or otherwise known to be in excellent condition?

2)Are you sure that the cartridge is optimally installed and set up, in terms of:

(a)Overhang
(b)Offset angle
(c)Tracking force (preferably near the upper end of the range recommended by Shure).
(d)Anti-skating force (if the turntable has a calibrated anti-skating dial, and its numerical value is set equal to the tracking force, it is most likely much too high).
(e)VTA/SRA (if adjustable)
(f)Azimuth (if adjustable)
(g)Capacitive loading
(h)Resistive loading

Also, try to describe more specifically the ways in which your records don't sound good.

Regards,
-- Al

09-08-12: Toxicwaterfront
It's a lot clearer and I can hear more things. With vinyl, it's like the music is masked behind a veil, and with digital, the veil's been lifted. Don't know how else to describe it.

My NAD doesn't have a phono input. For my analog system, I'm using the built in phono on my Denon. I'm starting to think it's either that or my cartridge.

I second your suspicion and ACMan's comment that the quality of the built-in phono stage is likely to be a major contributor to the problem.

Also, re item 2(g) in my earlier post, many Shure cartridges (what model do you have?) require load capacitances in the vicinity of 450 pf, which is far higher than the recommended load capacitance for many or most other moving magnet cartridges, and is therefore likely to be much higher than the non-adjustable load capacitance that is actually provided by the turntable's built-in phono stage. That would probably result in a large frequency response suckout somewhere in the treble region, which would contribute to a lack of clarity and detailing (such as you appear to be describing). Using a properly chosen external phono stage should allow you to achieve a proper match, in conjunction with the added capacitance of the interconnect cable.

Finally, I repeat my earlier question about whether or not the geometric and mechanical setup of the cartridge has been done correctly. Any or all of the adjustments I mentioned, if sufficiently misadjusted, could turn a potentially satisfactory turntable/tonearm/cartridge combination into an unsatisfactory one.

And one specific issue I see is that the manual for the Dp-300F, which I suspect is the same or similar to the model that you have, indicates on page 3 (pdf page 6) to set the anti-skating knob to the same value as the tracking force, which I had cautioned against doing in my earlier post. Try 60% of that value, and fine tune from there by ear, and also by checking that the stylus/cantilever assembly on the cartridge does not deflect significantly to the left or the right (as viewed from the front of the cartridge) when the stylus is in the groove of a QUIET passage on a ROTATING record, compared to its position when it is lifted off of the record. I suspect that if you perform that visual check now, when viewing the cartridge head-on (from the front) you will see the cantilever deflect significantly to one side when it is lowered into the groove of a rotating record.

Regards,
-- Al