Where to start

for me....actually, my Ipod Touch with my Entymotic Research earbuds is quite satisfying.

I checked to see if your Sony SACD player in hopes that it would have a digital input and could be used as a DAC.

I have a Pioneer Elite PD-D6-J SACD player and also a Maverick TubeMagic D2 (all available upgrades) DAC (both tube and solid state outputs) and I cannot tell the difference between a CD or SACD on my Pioneer Elite SACD player and iTunes through an Apple Airport Express through the solid state output on the Maverick DAC. I can easily hear the difference using the tube output.

I'm a bit of a flat earther in that from my limited experience I don't have any real evidence that anything before the DAC makes much if any difference. Maybe the horizon will eventually develop a curve, but that's where I'm at for now.

The Maverick DAC is available under $300 new and the Airport Express is about $100 leaving you with some budget for the rest of the needed parts.

Rgc - Unfortunately, a single gadget that fits everybody's requirements is yet to be developed - and those that are out there often falls short in some respect.

e.g. the Pono of Fiio X5 are certainly portable and will play high res files, but
- their user interface may not be as flexible as other solutions
- their ability to interface to other "gadgets" is restricted
- and their SQ may also not be comparable to some other less portable solutions available.

Personally...

My own system uses an iMac + Audirvana to stream from a NAS drive to a v-link192 and then into a Schiit Bifrost DAC - not portable at all, but the interface offers the ability to view tracks by artist, album, genre etc..., the NAS drive is a RAID morror (i.e. data is safe), and the sound quality is extremely good, whilst I control playback from the comfort of my chair via either my phone or my tablet.

I am fortunate that both our cars can play music from a USB stick, so my need for portability is addressed by that. Although it can be a PITA to convert to MP3 - I see no need for 24/192 in my car - too much road/wind noise :-(

I have a quality portable mini-system that has USB playback ability for music in the garden

I do not have a requirements for a personal portable player - and if the need should arise - my smartphone does a reasonable job.

So to summarize...
- I looked at the gadgets I had and what they offered
- I decided I was happy with what I had from a portability perspective
- I decided that from a streaming perspective - I wanted very high quality playback via my audio system that offered a flexible interface and security of my digital library.

Since you cite portability and the fact that currently you use vinyl and SACD most of the time for serious listening - perhaps the Pono or Fiio X5 would be your best approach for the time being.

Other solutions start to get expensive and may require you attain some technical knowledge about routers, computers and software.

You may well find streamed music to be more convenient to use and opt for a more dedicated solution in the future.

By that time - there may well be a solution that does everything you want.

It took me about three years to get to the point I'm at now and advancement in technology provided solutions to my mobile requirements.

Bit of a ramble, but I hope it assists in some way :-)

Thanks for the responses. It sounds like it will just be a matter of preference for me. I have a local audio store that sells Bluesound stuff. The vault may suit my needs and looks interesting.