Why does Computers - Amp - Speakers sound better?

I have a budget system. Denon turntable, Shure cartridge, NAD integrated amp, and Wharfedale speakers. For some reason, computer -> amp -> speakers sounds SO MUCH BETTER than turntable/cartridge -> amp -> speakers, even when the source file on the computer is 256 kbps mp3.

I don't know why this is. It would make sense if my amp and speakers were leagues above my turntable or if the source file was in 320 or FLAC, but that's not the case. 256 kbps should not sound better than high quality vinyl of music from the past five years (i.e. not mastered from bad tapes).

Is my turntable or my cartridge (or both) inferior to my other equipment? Also, I'm using Monoprice cables for my computer ---> amp and off-brand cables for turntable ---> amp. Could that be why?

thank you. The reason why this bothers me is because I spent over 1000$ on my vinyl (not just for the better sound, but because I'm deeply involved with the new-wave punk scene) and $400 on my turntable/cartridge and it bothers me that a low-quality file produces better sound.
What do you mean by "better"? Audio is a 100% subjective hobby. As long as you like the sound from computer "better", there is no need to ask why; just enjoy it.
You are making a lot of assumptions. "256 kbps should not sound better than high quality vinyl of music from the past five years (i.e. not mastered from bad tapes)." Why not? How do you know the tapes are bad? To get anywhere, you are going to have to listen to the same recording on both sources. That will at least give you a frame of reference to start with. Just to clarify, get the same album on CD and record. Also, make sure that one is not a remaster and the other one is. They have to be the same. Also, when you import the CD, try it different ways (lossy, non lossy, FLAC, WAV, etc). Doing it this way makes it much easier to focus on the equipment.

For me personally, I can tell you that I prefer older vinyl recordings that have no digital in the chain. Newer recordings or digital remasters sound like better digital and not like analog. I don't think its worth the extra time and money. Keep in mind, thats just my opinion.
If you aren't "level matching" between sources, studies say the louder of two things being compared will be thought to sound better.
My first thought is you need a good phono pre-amp, one better than the internal phono stage in the NAD, but I'm not a vinyl guy. I agree, 256K rips shouldn't sound better than your vinyl rig. How are you getting the signal from the computer to the amp? Are you comparing vinyl and 256K verions of the same song?
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:

(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.

-- Al
Have you tried recording your vinyl to digital and comparing the sound to your 256k files. Exactly how is it better?
Because the computer is low resolution and it is not bringing out the warts in your system.
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've level-matched and listened to about a dozen different records and their respective source files. Only once has the vinyl sounded better than digital, and that was only because it was a very busy ska record and the vinyl helped me distinguish the individual instruments.
And yes, I'm listening to the same album on both vinyl and digital. I'm not comparing two different ones, lol.
Took a quick look at the owner reviews on Amazon and noticed, as I suspected, that most are bypassing the built in Preamp and using a external phono amp of better quality. While I don't believe you have to spend $$$$$ to get good sound, it is asking a lot of a turntable/Preamp combo at that price to be better than digital.

I listened only to cheap turntable's and whatever phono was in the receiver until I was around 30 years old, and when CD's came out they sounded better than what I had been listening to, so I changed to CD's. Twenty years latter,after purchasing a good preamp, one with a good MM phono stage, I purchased my next turntable and am really enjoying my 1000 lp's I had stored all that time.

A while ago I set up my old cheap Rotel turntable into my mid 90's Onko receiver and guess what? It was horrible . The phono stage is very important, and cannot be overlooked! Everything is important!

I would read the many thread's on good budget phono amps, and save my penny's until I could afford it, or purchase a good old Preamp or receiver which is known to have a good phono stage in it.

Sorry for the long post. Good luck

The description of a veil being lifted sounds a little bit like it could be a VTA too low issue, but it equally could also be the cartridge or the phono pre. Is the sound muddy and lacking in resolution in the highs?
No it doesn't
I'm still curious to hear how you are getting your 256k files to your speakers. Your NAD doesn't have an internal DAC, does it? That means you must be using an external DAC. Are you using Mac or PC? Optical or USB? Do you use a USB/SPDIF converter? You've detailed out what gear you have on the vinyl-based side, it would help to hear what you're using on the digital side. Just to get the full big picture, thanks.
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.

-- Al
Part of the effect is the improvement achieved with near field listening, which has certain advantages - focus of the speaker (and short distance to the ear) and a directivity of sound that eliminates several 'room' and 'extraneous noise' issues. Some car audio 'sounds' subjectively great because of the enclosed nature (within the car) of the speakers and the more direct interface with your ears. I've even noticed a somewhat similar positive effect with some ceiling speakers - in quiet coffee houses for example. Some of it too is that our 'listening expectations' are low, and it is a pleasant surprise when clear (low noise computer/internet radio)sound is produced in a public environment; the WAY we listen is different than the way we listen to a dedicated stereo. It is very easy to pursue a 'perfect' sound, actually achieve it (or get pretty darn close), only to find that it's not as enjoyable because so much time/money/expectation is involved to hear that perfect performance. Then its time to 'downsize' or 'simplify'. And then we get to start all over again. :-D
In any particular case, either turntable or digital might sound better. It all depends on how well each is set up to meet the needs of the listener.

In general, it is harder (and probably more costly in general these days) to achieve a quality turntable system than CD/digital. There are a lot more variables to consider and more technical know how involved to get a turntable system set up and tuned properly in general than CD/digital.

I'm guessing these days $2000 or so is probably the minimum amount one might expect to have to invest in a good quality vinyl rig (table, cart and phono pre-amp combined) to even have a chance out of the gate of matching or exceeding even a decent digital setup that might be done for less than half the cost perhaps. I'm sure others have experiences here that might help refine these estimates.

You have to start with the cartridge. All the rest is supplemental to allow the cartridge to work optimally. My experience is the Denon DL103R cartridge is a good place to start to have a chance for minimal cost but care must be taken to match it to a good quality table with medium to high mass tonearm and a decent phono stage that can work well with a low output MC cart like the DL103R.

FWIW, I use the DL103R, a vintage Linn Axis table, a Electrocompaniet step up phono pre-amp, and an ARC sp11 pre-amp with phono stage. Substitute a decent outboard phono pre-amp for the ARC pre-amp with integrated phono stage for use with a basic pre-amp minus phono stage and the cost probably comes in just under $2000 used. I can assure that the results are top notch for very reasonable cost assuming all gear is in good working order and set up correctly.
regarding cost of the digital front end, I have about $900 in mine, *not including the laptop.* I still plan to buy an upgraded USB/SPDIF converter within the next 3-4 months, that will bring it up to about $1300-$1500.
I actually did do a comparison, vinyl/digital, in my system, a friend brought over his budget turntable and we had a shoot out. He didn't like my Halo P3's phono stage, so we ran his single-ended outputs into the direct inputs on my pre. The vinyl front end was very enjoyable, considering the cost difference! We put his vinyl 'obscured by clouds' up against my recent digital re-master of the same album, and I really didn't prefer one or the other. But convenience won over eventually, we got tired of flipping plastic discs, and started picking music on the iPad...