[Luminair]

Looking at some of these USB DACs and they shut off the second output when the first is plugged in.  Which DAC has a **** switch on the front?  Keep it under a million Zimbabwe dollars please!

 

[Remonster]

I use the Fiio E9 which has two headphone jacks on the front. One is 1/8" and one is 1/4" and both can be used simultaneously. I don't have experience with any other headphone amps besides the Nuforce uDac-2 (which mutes output to the Line Out when headphones are plugged in) so I couldn't tell you about any others but I do like my E7/E9 combo for the $200 I paid.

 

[LCfiner]

simultaneous output? just get a pair of RCA splitters or a single 3.5mm splitter and connect your two outputs. it’ll cost a couple bucks
 
I’m using the RCA splitters now with my MS2+. works fine.

 

[Luminair]

ESI/AudioTrak/Jineung/JAVS Dr.DAC Prime ($500 ebay)
IZO iHA-21 ($asia impossible)
Audinst HUD-MX1 ($200 value but no switches for gain, or input, or output, or fixed/variable line level output, and no analog or digital input,)
Audio-gd NFB-12 ($250)

 

[Luminair]

DR. DAC2 DX ($300 ebay) http://www.audiotrak.jp/product/DR_DAC2_DX/
PRODIGY CUBE ($100 ebay) http://buyaudiotrak.jp/goods_detail.php?goodsIdx=619

 

[Luminair]

STYLEAUDIO carat-hd1v or carat-peridot or carat-ruby2 or... ($100-200-300-400 ebay... http://styleaudio.jp/php/peridot.php)
Creative X-fi HD USB ($60, has some frequency deficiency made up for by automatic scaling, probably a non-issue but it also seems to be on its way to being discontinued . . .)
E-MU 0204 USB ($100-$150, no optical/coax SPDIF in/out)

 

[J.Pocalypse]

Go with the splitter. They're $5.

 

[Luminair]

Maybe: Topping D2, $100

 

[Luminair]

fiio e10 (cheap but **** design, clips on sound start)
firestone fubar (euro, high price)
 
both have simultaneous secondary output independent of headphone volume control
 
violectric.de (euro, expensive as all get-out)
Cambridge Audio DacMagic Plus (lots of features, good quality, expensive)

 

[Luminair]

hlly SMK-II ($200 china, nice front, coax but no opt)
O2+ODAC, really a mobile amp, or the ODA desktop amp when its done