is a modded OPPO 105 a dandy cdp ? It has digital out, so your dac of choice can be added ? Way cheaper than the 5000 dollar great Bryston, but that Canuck built cd3 has more functions and way newer.
The decision is not hard at all, just decide how you want to listen to music.
The modded Oppo 105 Blu-ray/CD/SACD player is like a Swiss Army Knife. A jack of all trades, a master of none (it does have excellent Blu-ray). But as you discovered it has a digital out.
The Bryston BCD3 is like an expensive chef's knife, it does one thing extremely well: play CDs. Of course it has digital out too but not many people buy it to use as a transport with a DAC, kind of expensive for that. Think of the BCD3 as the best CD player for luddites who want state-of-the-art sound. No DAC needed, just one simple easy to operate box. But
the BCD3 does not have a digital input so it can't be used as a DAC, so you will still be stuck listening to Mac music using your crappy old DAC (which is where we started).
Having never heard a modded Oppo 105 or Bryston BCD3 I can't say how the sound would compare but based on all the reviews I would bet the Bryston would blow away the Oppo. The BCD3's attention to jitter and dual AKM chips along with a new state-of-the-art CD tray have the Oppo beat even before the unit is turned on.
But you just bought an Oppo something-or-other so you have a very nice transport (and Blu-ray player) with digital out already. When I read the reviews comparing the Bryston CD player to their DAC the DAC won for sound quality. So with a DAC you can still play your CDs using the Oppo.
But wait there's more...
Plug your Mac into a DAC for clearer sound compared to what you are using now.
Plenty of very good used DACs so you don't need a Bryston. I picked Bryston because it has SACD input but since you don't have any SACD disks and don't know what they are then that function is moot. I'll let others make suggestions based on your price range. Brand and model is based on your speakers and electronics, we don't know.
You could have $30,000 of stereo stuff or an old Sansui receiver with the Large Advent speakers from the '70's.
And are you still buying new music? How? I download all my music, no need to go out shopping or wait on the mail when I can have instant gratification.
BandCamp is one of the best and cheapest places to buy music. If I hear of a new band I see if they are on BandCamp, listen to their music and buy 16bit/44.1kHz flac albums for $10.
https://bandcamp.com/Plenty of free converters to change flac into WAV and burn a CD with your Mac to play in the car or use in the Oppo or convert to AIFF and add to your Mac digital library.