[sclee]

I try to design a USB DAC powered by usb port.
We plan use PCM2707 I2S output to PCM1794
For mobile reason, i don't want powered with external source.

The problem is, for I/V TI suggest use NE5534 which require +/- 15V.
I try to found another good opamp worked well in usb power and no idea.
All low voltage opamp are bad.

I could like only use a resistor transfer to voltage and connect to our battery powered headphone amp by AD8620 4 gain.

By reference the web site on here
DAC Final
I could like use two PCM1794 with 100ohm, which output about .4 V rms.

Is it possible for this design ? Why need opamp for output if i have a headamp ?

 

[cobaltmute]

http://www.head-fi.org/forums/f6/try...design-385013/

The LMH6643 sounds pretty good (very detailed, but not overly sharp), while a LME49721 give up some of the detail but give some more perceived thump in the bottom end.

 

[dsavitsk]

Start here http://www.head-fi.org/forums/f6/hpdac2-hpdac3-244004/

 

[sclee]

Thank you. Those information very useful.

I try to plan use AD8652 1pcs+AD8651 1pcs.
From database, the speed and performance very good with very low THD but it need 9ma per channel. Which require 9x6 = 54ma on I/V.

The current of DAC require should need about 250ma.