Like any trade, it ain't the tools so much as how you use them.  better tools won't make a better recording, necessarily, but doesn't hurt.
 
Although better mic/preamp/converter fill-in-the-blank can help around the margins, it doesn't make the difference.  However, I wouldn't discount a pro saying he can hear a differerence.  The longer I work the more I think I can hear subtleties - and use them to my alleged advantage.  It doesn't mean my older work sux because I didn't use X on Y, just that new songs might be a smidgen better.  Hopefully, one's technique gets better as well as the toy budget.  That is a nice combo, tho it makes it hard to quantify that this vintage tube preamp is 10% better than my old IC one.
 
There are people I know that use high-end tools and it has as much to do w/ the way they work (and the speed) as the tool itself.  They know what a bass sounds like through a UA tube channel and it allows them to get the sound they want to use w/ no muss or fuss.   Just as they know where in the room they like to put the amp/mic.  If it worked 100 times before, it is likely to work again.  Just like Danny, I venture, knows the capablitlies of both of his board preamps and uses them to his advantage, and knows where the room mic probably should go on the drums.  And after listening to the song probably knows which mic would work.  Not because he can travel forward in time, but having used that position and mic on that kind of song or drummer.  It is a matter of experience.
 
It is kinda of silly to quantify the difference between two pieces of similiar equipment - it only works in a vacuum.  And even if they are the same, if the engineer is used to one piece of equipment, he is likely to use that one with more confidence, if not better.  So for him, it is better.
 
@

 
This is an interesting thread I stumbled on recently:
 
http://www.groupdiy.com/index.php?topic=42089.0
 
You can see, fairly easily, that, at the mid price point, there is always room for improvement.
 
If they hooked that thing up to a big battery it would probably sound even better.
 
 
best regards,
mike

Danny Danzi
 
I've been saying that for the longest time as well, Mike. Someone made a mention in this thread about noticing the differences when you have large track counts...this is true in my experience as well. The cheaper interfaces sort of skewer mixes in my opinion to where they get harder to mix and place correctly.
-Danny

THIS. +1
 
the converter issue, really boils down to the depth of the capture, and how the number of tracks will have a big impact on the final mix.
 
blurry highs, muddy lows and mids, it all adds up as a collective sheen across the mix with higher track counts.
 
having high dollar converters DOES matter.
 
 
 
but, it all depends.

Bat,
 
that is something else I've noticed w/ high dollar stuff.  Lower cost analog does fine for most jobs, but gets stressed (crap out, I think is the technical term ;-) ) the closer you get to the operational limits.  Preamps, esp., show these signs.  I suppose convertors - the analog part of them, anyway, do the same.  The more signal, esp. finished product, you try to cram through them, the more likely the signal will get degraded.  It ain't the ADDA chips - they are mostly the same.
 
And a lot of time this isn't noticable if you don't know the warning signs, or if your montioring situation is less than good, etc. etc.  In fact, a less than optimum monitoring situation can smooth out some of the rough edges you'll hear on expensive monitors.  Instead of sounding worse on your computer or in your car, a song can actually sound better.  When I switched from a presonus firebox here at home to a TC Konnekt, I could hear a difference between the convertors, but for some of my stuff I liked the duller, more analogish sound of the Firebox rather than the highs in the TC.  Once I learned to use the tC, I got better separation in my mixing (and tracking, too, of course).  Better tools are, well, better, but not necessary if you learn to use what you are dancing w/.
 
To misquote Dirty Harry, "An engineer has got to know his equipment's limitations." 
 
@
 

this is why understanding GAIN STAGING is so important, especially for the home recordist.
 
 
you can push the better converters...
 
you cannot push the cheap ones.
 

batsbrew

Danny Danzi
 
I've been saying that for the longest time as well, Mike. Someone made a mention in this thread about noticing the differences when you have large track counts...this is true in my experience as well. The cheaper interfaces sort of skewer mixes in my opinion to where they get harder to mix and place correctly.
-Danny

THIS. +1
 
the converter issue, really boils down to the depth of the capture, and how the number of tracks will have a big impact on the final mix.
 
blurry highs, muddy lows and mids, it all adds up as a collective sheen across the mix with higher track counts.
 

My guess is if you guys are hearing more of a difference with higher track counts it's because individual tracks might make for lousy test signals compared to a full mix.
 
Because, assuming roughly similar sounding channels with real world signals, any differences would either be the same or progressively less as you add more channels.
 
The point being: one should be able to hear the differences in a much simpler 2 channel comparison test, given an appropriate test signal.

 
Is this going to require an appreciation of fractions?
 
 
60(1/60snr)=1snr
 
2(1/2snr)=1snr
 
 

yes

drewfx1

batsbrew

Danny Danzi
 
I've been saying that for the longest time as well, Mike. Someone made a mention in this thread about noticing the differences when you have large track counts...this is true in my experience as well. The cheaper interfaces sort of skewer mixes in my opinion to where they get harder to mix and place correctly.
-Danny

THIS. +1
 
the converter issue, really boils down to the depth of the capture, and how the number of tracks will have a big impact on the final mix.
 
blurry highs, muddy lows and mids, it all adds up as a collective sheen across the mix with higher track counts.
 

My guess is if you guys are hearing more of a difference with higher track counts it's because individual tracks might make for lousy test signals compared to a full mix.
 
Because, assuming roughly similar sounding channels with real world signals, any differences would either be the same or progressively less as you add more channels.
 
The point being: one should be able to hear the differences in a much simpler 2 channel comparison test, given an appropriate test signal.

Drew, whatever the heck it is...it almost seems like the cheaper converters (to me at least) give me more of a tape sound. The nice highs are not quite there, yet there is plenty of energy in the tracks as well as warmth. But when the track count gets higher, it's sort of like you have to brighten each instrument or something because you're losing fidelity. For example, in that guitar tone I was talking about...the Realtek version was warmer and a bit smaller in sound size compared to the exact same guitar recorded with a RME FF 800 and my old trusty Layla 24/96.
 
The RME and Layla sounds (yes, I re-recorded the tracks two times using those cards) seemed bigger in sound size. Meaning, if you were to solo one of the guitar tracks up and pan it all the way to the left, it literally sounded like it was bigger in size where the Realtek being panned like that made it sound like it was tiny and narrow...like a little bee buzzing around. The other thing I noticed was, the RME and Layla had this presence that the Realtek didn't have. Not a harsh high end presence, but more "hype" maybe? I purposely did NOT set the RME or the Layla to 16/44 because I wanted to hear how much different 24/48 would sound compared to the Realtek at 16/44. 
 
Thinking back, I wish I would have done that just to see how the RME and Layla would have sounded in that bit/sample rate. I don't think I would have heard much difference because in the past when I have been sort of forced to work in that realm due to clients, I've not noticed the sounds I added to their projects sounding way different. Like sometimes someone had already started a project somewhere else in 16/44 and they come here...so to try and keep things uniformed, I stay at 16/44 and they may ask me to play some guitars etc. I never notice my guitars sounding like they sound when I record with the Realtek. I actually LIKE what the Realtek does to my tone...go figure. I know....I need my head examined.
 
I think I want to do one of these tests again. It might be good for us to have on file anyway. I just gotta find the time for it. LOL! You know, record a minute of something using totally crap converters, then re-record the entire one minute project with my Layla, then the RME then the Lynx. I don't get a chance to use the Lynx much...that's at my other studio and they keep me away from there other than 1-2 times per week. LOL! 
 
-Danny

One of the points around the multi-track thing that I was getting at (IMO) may have to do with the clock that is used within different converters and interfaces. Maybe the AD/DA chips are not all that different, but perhaps the clocking mechanisms are more consistent on the higher end devices. I use an external clock, and to my ears this switch made a noticeable difference in clarity over the same monitoring system, etc. To me, this makes sense. If there is jitter in a clock, there perhaps is some time shifting forward and reverse which may "muddy" things. Whereas, if things are locked dead-on all the time, clarity/fidelity would be more apparent.
 
Just a thought.