FIIO K13 DAC R2R Headphone Amplifier 32bit 384kHz DSD256 Black - reviews - There are 2 reviews.

FiiO K13 R2R DACamplifier
Absolutely superb. Everything I hoped it would be and more! If you're hesitating to buy then don't! Apart from the obvious compliments about sound quality and power, I love the parametric EQ in particular. I added a large dose of sub bass to the EQ for my DT770 PRO's and the results were absolutely staggering with electronic music from Yello for example. To have what amounts to digital tone controls is marvelous. I have hearing damage around 4khz and I'm able to correct for this so easily!
Sound is often holographic with Planar Magnetic IEM's or headphones. Occasionally, with certain genre's, the music almost seems to get lost within the soundstage! Strange until used to it.
The flexibility the K13 provides is excellent! Lots of inputs and outputs balanced and unbalanced lots of menu options, remote control ,great LDAC 96khz 24bit Bluetooth implementation, excellent build quality etc. etc.
I hate to say it but I think this unit is priced way to low! Unusual to be able to say that itoday! Thank goodness for companies like FiiO. I can't imagine how much a device like this would have cost 20 years ago especially with an R2R DAC inside!
I would say that the K13 would probably be end game for most users like myself who are discerning but can't or don't want to spend thousands more ...!
An easy five star buy for once.

Awesome
Love it, the sound quality is excellent, it has a lot of functions, and I can set almost everything to my taste except the colors of the lighting.