[mca]

A. Slimdevices Duet/Bolder power supply/Bolder digital mod/Red Wine Isabellina DAC

or

B. Modwright Transporter

[Big Red Machine]

Oooh, not really sure I want to step into this but I wouldn't be planning to spend that much on either choice.  I am very happy with my SB with dig mod, CIA PS, and Cullen DAC (or perhaps the AVA Insight) for way less bucks.  You can do this for $1600ish.  And if I did choose the TP path I'd go used but here's where those who have experienced them both need to step in and give the DAC highlights of each.  I'll bow out now.

[mfsoa]

Can I vote for Transporter>>Bryston DAC?

Haven't heard but I can dream.

[lonewolfny42]

Mike/mca....
What are you using now as your source ?

Edit :  I think I found the answer...

[Bigfish]

If you really want to spend $3800.00 for a source consider the following:

1.  How do you feel about buying and rolling tubes?
2.  Does having a one box source versus multiple boxes make any difference to you?
3.  Do you have $3800.00 to spend at one time or would you prefer to spend the $3800.00 over time as the money becomes available?
4.  Which unit do you think will bring the best resell value should you chose to sell in a year or so?

The answer to these questions should lead you to the source that best fits your needs.

Ken

[Mariusz]

I will use my Sonos (I am also planning to upgrade it with Cullen circuit) and Wadia iTransporter with Isabellina dac.

Mariusz

[denjo]

Duet (Bolder modded), Paul Hynes' PSU, Bryston DAC-1 and the remainder on CDs! 

[Imperial]

Empirical Audio also has several offerings from 3 -4K with options running in many directions and setups.
Benchmark, Northstar, sonos, olive, transporter, squeezebox3 setups and so on.
Usb, I2S, spdif connections.

I'm sure that one could mix and match between several of the mentioned brands here quite easily!
Bryston, Modwright, Boulder, Empirical, Hynes (psu's...), RWA ++!

Tube Research also mods Audio Logic dacs 24 and 34 types (They have I2S inputs..) you know. Said to be very good this!

I would most likely start with a macbook I guess, and take it from there!  Add a large UPS battery pack.
Have it run 10-14 hours at a time from batteries and stuff! That would work cool I'm sure!

Imperial

[wilsynet]

I'd get a Macbook for $1K, an iPod Touch to use as a remote control, and the Isabellina. You'll get fantastic results using USB.  The Apple iTunes Remote software is a joy to use, and a MacBook is more powerful and flexible than a Transporter or Duet, and every bit as good as a transport.