FiiO doesn't seem to know what brakes are, releasing more products than pretty much anyone else in the audio space. Its desktop line of sources is just a subset of the gigantic product library it boasts in 2024, and there are new product lines being added too. The R series (R7 and R9) add network streaming with an Android system on top of being a desktop DAC/amp, and now we are also seeing standalone streamers, CD players, even cassette players! But if you had to ask me what FiiO is most known for, I'd say that would be its line of portable and desktop DAC/amp combo units. The likes of the K5 Pro ESS, the K7, the K9, and the K9 Pro were so profitable that FiiO is now midway through its new generation, with the K19 being the new flagship and the K11 being the other boundary. The FiiO K11 released a few months ago at an MSRP of $140, and currently can be had for ~$120, if not under, at some places already. I have seen so many of these K11 sources used in person too, offering an exceptional value for its feature set. So when FiiO announced a K11 R2R, it got a lot of attention and anticipation alike.

The newer K11 R2R switches out the Cirrus Logic CS43198 DAC for FiiO's in-house developed 24-bit R2R DAC, and maintains most of the other features to make for the least expensive modern R2R DAC/amp. It managed to steal the thunder from HIFIMAN at the same time, which has $299 R2R DAC/amps now. The K11 R2R undercuts these by more than 50%, and I'd argue offers more features on top. Take the screen, for example, which allows for plenty more customization than what some discrete buttons can do. The RGB indicator LEDs are also nice, and FiiO sees the light show some of you like to have on your desk to now allow users the ability to choose the color of these LEDs, in addition to having a proper breathing mode lighting effect too. The addition of the screen and the 4.4 mm balanced output makes this a big upgrade over the K5 Pro ESS it aims to replace in the product line, and arguably gets close to the K7 too for most people. The standard K11 is arguably the safer way to go, offering a default, safe sound from its delta-sigma DAC. But those curious about how R2R DACs sound will no doubt find the K11 R2R compelling. It's far from being the best sounding R2R DAC, and has some issues with more sensitive IEMs in particular, source synergy is certainly going to be a thing you will know more about as you will find this sounds better with some headphones than others. NOS and OS mode selections help offer two different takes on how the chain will sound, albeit again the difference is not day and night. It's fun to try out though, and the value offering is hard to beat. I am happy to give the FiiO K11 R2R a conditional recommendation, and would also suggest looking at the standard FiiO K11 as well which is even more impressive for the money.