Why did this just happen ?

I would assume it's just a matter of how much DAC technology has improved in 8 years, but that is just a guess.

Tony,

I thought of that but it isn't converting . I've chosen my Benchmark DAC as the playback source.

I just noticed my audio/midi set up and it seems it is up sampling to 96k. Perhaps that wasn't available in earlier OS. 

Computers are notoriously bad streamers.  Replace your new computer with a real streamer and you may get a similar upgrade.

What is a real streamer ?

https://letmegooglethat.com/?q=audio+streamer

By real streamer he means a dedicated audio streamer. Virtually any will outperform a pc. I have used iPads, Macs, PCs. When I finally reluctantly upgraded  to a dedicated streamer the digital leg took a huge jump up in sound quality. Since then I have used many. I recommend Aurender, but there are dozens of brands like, Aurlic, dCS, Bluespund, Linn… the list goes on.

They come as either just a streamer or streamer and DAC. Just a streamer is recommended. Streaming from Qobuz produce sound quality as good or better than red book CD and my really good analog end. Highly recommended. 

Perhaps a faster processor speed and or less jitter?

My $.02. 

Since I'm not an Apple anything fan....

If you're using a pc, m/bs' for gaming will help since the concept is speed at all costs....this includes audio as well as video.

Apply the best soundcard you can rationally afford, as audio 'cues' in games can mean the difference in 'game life v. death'.  Comments from players about 'hearing something from Behind You' early enough to respond to avoid having you butt handed to you....

Max your RAM with the fastest you can find for the m/b and processor...'garbage in = garbage out' still applies...

Look....the bulk of pcs' and macstuff is aimed at the 'average abuser'.

Bite the process and Build a 'puter that will do what You want it to.

You can still use your DAC....although that process happens in your laptop daily.

(...I'm in a rare PO'd state, and tired of 'hearing' "...I spent XK$ on a DAC/streamer/magic box that I'm disappointed with..." which has the basically the same innards as a 'built puter' for more or less the same outlay....

For 'techno types' as most seem to aspire to or claim...

...y'all are disappointing....

...and y'all can start flinging dog waste at me now....

@wturkey ....you're excused from the previous....

At least, you asked....👍

I think it’s the sampling rate, dropped bits, or elimination of noise on the USB. PCM uses packets to wrap up and send information. If it runs out of time, it drops bits. The cost is resolution. Computers are getting better and better at this. It’s why I went to DSD back in the day. 
 

Full disclosure - I’m an analog guy. I do use a PC for my digital (the horror) but I do not stream. Everything I listen to I have spent the past 25 years recording and cataloging myself from analog sources. For how I use it, it’s fine for me. Say what you want to say about PC/Mac as a source, I don’t have enough years left on this planet to redo that work. You didn’t say if you were streaming or playing from your drive. If you’re going to consider a streamer and you have cataloged your songs, I would look very hard at the interface and how it could hold onto that information. 
 

Regardless, this sounds like a good problem to have. Congrats and enjoy. 

Less noise

You didn’t specify which MacBook Pro you are now using. If it is one with the M1 processor, that is part of the answer, plus better/faster processing from the ram, storage, and input and output. Beyond that, results will vary depending on what else is connected to the Mac, and what other software is running. Changing the USB output cable to accommodate the USB C likely also contributed some to the change. Speaking from some experience going from an old Mac Mini 2011 to a new M2 Mac Mini 2023. Even with the newer processor which stepped sound quality up, a new better USB cable also made a difference.

@eugenegearty

Always refreshing to hear good news when new "stuff" is swapped out and something positive happens.

I’m with @budjoe on this one. Changing to USB C indicated a definite change in cabling. The "sonics" of cable changes can range from "whatever" to precisely the phenomena you described -- "wonderful improvement."

What to do next? Staying the current course, maybe get your hands on some (really good) USB C cables for a listen? Taking it to another level, perhaps try a dedicated (real) streamer? Or, as @asvjerry suggested, contact a computer guru (or become one yourself) and build a box that can rapidly calculate the Drake Equation as well as spit music out the back of the box.

Enjoy.

What dinov said, less noise.  You went from a noisy old iMac with a built-in AC-powered switching supply and a big ol' screen, to a laptop with a DC supply powered from an external source and a much smaller screen.  You also upgraded the processor, memory, etc.  As others have said, now try a real streamer.  It doesn't have to be terribly expensive, about the same as the Macbook, but it will be even quieter and more resolving.

The MacBook Pro has the M1 chip. As you can tell I don't buy new stuff, in fact my bought used Koetsu Rosewood cartridge has been re-tipped 3 X. Crazier than that I have a Well Tempered Turn Table. So pretty much all my gear is from last century. The good news is it sounds REALLY good.My Benchmark USB DAC was an up grade from everything Audio Alchemy made. CD transport/DAC/anti jitter clock...Which was an upgrade from a Mod Squad Marantz CD player circa 1987.

I mainly play my records ,though a good digital front end is handy.

I am not interested in streaming in any form. My 2TB SSD has thousands of my CDs that I ripped over the years at the highest bit rate and AIFF format. The many HD tracks that I DL @96k also sound very good. So using a Mac and iTunes as my interface is not going to change. I was just amazed that a $400.00 upgrade in a PC made such a difference . The USB C output goes to a USB B hub so I can get to my Benchmark DAC.

Thought you geniuses had a detailed answer. No problem I kinda don't even want to know. My ears tell me everything.

Thanks

If all that's changed is the computer, it's most likely the USB section is better in the newer MacBook. I suggest getting an iFi iPurifier 3 too. It's about $150 on Amazon (risk free easy return if you're dissatisfied). It's made my streaming setup really good: lowered noise floor, increased musicality (yes, I know that's a subjective descriptor). In short, I won't part with mine.

USB uses the internal processor to handle everything. Speed and detail is all put on the processor.  This is like when you are moving music files onto an eternal HDD, on an older computer it will be so slow, put on a new computer, the speed is much faster. 

Then factor in all the new technology of a new computer, plus better CPU/RAM/HDD and updated software. 

USB is a horrible transport for just about anything, but it has become the standard. https://www.howtogeek.com/53587/usb-explained-all-the-different-types-and-what-theyre-used-for/

@waytoomuchstuff ....I've been interconnecting Winboxes to the audiophilia stack before spouse got a gig as the landscape maintenance manager for the complex we got to live in as part of her salary package....

It just 'happened' to be tied into a T3 cable to a local software design/implementation firm a mile away.....full motion videos f/t when the local cables would stststutt er with mpegs.....It was funny when they'd call to hype their service...

"S'cuse, but we're on a T3 link here...."  The smart ones would be impressed and wish us a good time...the others?

"Ask your super what a T3 is....and hope they keep you around..." and hang up.

Place was full of geeks, gamers, day-traders looking to trade seconds for dollar$....
Near zero latency....

The server had an music file directory that was Huge.....and got shut down during that whole issue that got some sued by the labels involved.
Those that saw it pending downloaded anything they wanted, but disc drives were still in megabytes and the eq of a t-byte drive would outcost the 'puter you were running....

'Ell, your cell is more capable now....and I'd already been doing 'room eq' for a couple of years prior to that stint....

@nyaudioguru That ifi iPurifier sounds like a worthwhile widget, but I'm concerned over the surge in esoteric 'puter cables that would undoubtedly price like audio cabling does now....

I'm backing up some of my more 'important' connections with opticals, just to see what may lurk there.....kinda leaves the turntables out of the picture, but analog be analog and should be enjoyed as such....

@mswale, yeah...USB ain't perfect, but 'market forces' can trigger all sorts of this'n that to occur...and if enough push for it, noisy power supplies can rise to 'phile levels...although having those rise in co$t will not be a surprise when they do....

My dedicated audio 'puter is already so non-SOTA, and I took it as far as I could manage at the time...and in the case that I've clung to since HOU/T3 time....(looks and sized like an average receiver/pre/amp and fits rack mounts....)

My primary guess would be that the newer Mac has a newer OS with improved drivers for the DAC, and that what you were using before was "crippled" relative to the driver. 

Either that or you find the effect of using a hub between your Mac and DAC to be euphonic and pleasing.  Just in general, USB hubs are not recommended for use with DACs, so you might want to connect directly.  

Hey @ BTW....if y'all are deep into your 'phile items, DIY'ing a 'puter isn't as deep a chore as one is already with your gear....more or less....

Pick your processor and match the m/b to it....select the suitable RAM chips, and stuff the slots FULL.
You want speed...there's charts online to guide that... ;)

Start 'fresh', you'll want your current lap or box for info and guides.

T-drives are ridiculous cheap lately.....but use a SSD drive for C:

There's audio cards available now that I couldn't afford or didn't exist at the time.

Find one...not just for 'now', but for Later,

What and to what to 'out' to is potentially another rung on the upgrade spiral....

Case in point:

Studios have been in digital for awhile now, with some analog diehards still in the mix.....

You Can't Beat Them...."Surrender!   ...but don't give yourself away..." ;)

Strip all the BS from Win 10 Pro....11's got 'issues', in mho.....and can be downloaded cheap....and you can keep it, and register it.

We're AMD fans here....Intel is too big, and we're underdog types.... *g*