Here's another good option. I believe the output impedance is 2 kOhm and I don't know what input impedance is on your amp, so something to check. If you're after transparency, this will be tough to beat.
http://www.placetteaudio.com/passive_line.htm
Here's a review for more info FWIW...
http://www.10audio.com/placette.htm
Best of luck.
http://www.placetteaudio.com/passive_line.htm
Here's a review for more info FWIW...
http://www.10audio.com/placette.htm
Best of luck.