cd transport or pc for SQ????

Not necessarily.

Too many variables, including where you set the bar for "high end", if you are thinking of something like the Reimyo CDP @ around $27K then almost certainly, but back in the real world where most of us live, many (particularly headphone users) rely almost entirely on PC sources and some very competent computer based sources have been purpose built.

Once your CD is ripped accurately using readily available software and stored on your HDD the quality of the playback from your CD-Rom drive is inconsequential.

There are a number of issues to consider, but the greatest factor in SQ obtained will come from the quality of DAC and your ability to feed it the cleanest signal possible.

The electrically noisy interior of a PC can be a source of signal contamination and jitter, approaches such as using external soundcards connected by USB or Firewire is one solution, as also are DACs having USB input.  If the DAC reclocks the incoming signal then jitter will be reduced.

When you say PC I am not sure if you are talking of a desktop machine or a laptop, the options may vary a little depending on which you use.

A number of people of my acquaintance who use desktop machines are quite satisfied with the analogue output from a good quality soundcard fed to a Solo or other quality headphone amp and I have owned standalone CD players that did a worse job than a couple of the soundcards that I have here.

So, not by any means are you condemned to second-rate by using a PC source.

How much difference does the transport make ? - that is a question that has sparked many a lively debate.

As an indicator, early this year I attended a gathering of audio tragics for a "source shootout", there were around 20 in attendance and sources varied from an old cheap CDP through several $1K - $3K models and up to an $8K Wadia and also included a laptop fed into a USB DAC that can be purchased online for around $700 (pricing in $AU).

Levels were matched and all sources fed through a switch box to the same amp and speakers - which player was connected to each number on the switch was known only to the setup man.  There was no discussion during comparisons but free switching at request was the order of the day.  Attendees took notes and selected numbers according to their rankings eg player no 1 worst, player no 2 third, player no 3 first etc. notes re various aspects of SQ were also made.  Afterwards the setup man collated all the result sheets, unsurprisingly the Wadia ranked first, surprisingly the USB DAC ranked second, the others more or less in order of price, ascending.

The differences were not as obvious as might be expected and my feeling was that a longer period of evaluation with a wider range of music might be necessary to fully appreciate the superiority of the most expensive machine, its strengths were definite but subtle and it was probably more evenhanded on a wider range of material.

In other words its strength was its lack of weaknesses rather than an "in your face, blow everything else away" presentation.

Do note the second preference, a laptop with a USB fed DAC, this from a group of around 20 fairly experienced listeners choosing on SQ.