This is a review and detailed measurements of the Schiit LYR 2 tube Headphone Amplifier and Preamplifier. It is on a kind loan from a member. The LYR 2 is discontinued but was a very popular device for its time. I think it sold for US $449 when new.The unit fits the typical mold of Schiit products:There is nice, heavy feeling volume control in the front and 1/4 inch headphone jack.The owner was kind enough to not only send me his set of Octal LISST solid state tubes and a set of 6BZ7 tubes. I tested both. FYI I spelled the solid state tubes "LSST" in my slides.The back of the unit is self-explanatory:I though the output was a real pre-amp but seems to be a direct tap from the headphone out (possibly with an inline resistor).A power supply is included in the unit which makes it very heavy for its size.In use, the LYR 2 cooks and cooks good. The entire chassis but especially the right side gets extremely warm. It does this with either tube options. The heat generated must be coming from the output stage and/or power supply. It certainly runs too hot for my taste and likely shortens the lifetime of the components inside.I was set to test the unit both as a pre-amp and a headphone amplifier, starting with the former. But after a few tests I realized they are one in the same so this section is truncated.Let's start our dashboard view with LISST solid state tubes:The volume control was adjusted to output 2 volt for the same 2 volt input ("unity gain"). THD+N and hence SINAD is dominated by the second harmonic, giving us a SINAD of 89 dB.Oh, there is a typo above: it should high gain drops to 77 dB, not low gain.Switching out the LISSTs for the Canadian 6BZ7 tubes costs you dearly in performance:Our headphone amplifier champs have no worries with respect to Schiit LYR 2:Frequency response was excellent with either tube option:Here is the intermodulation distortion versus level up to unity gain:The "real tube" clearly underperforms the LISST solid state solution.THD+N versus frequency was an eye opener:The LISST option holds distortion down until just 200 Hz after which it increases proportionally with distortion (in log scale). In some sense then, our dashboard using 1 kHz tone is favoring the unit.Switching to 6BZ7 produced that continuously high THD+N although it seems to beat the LISST at highest frequencies (???).I was curious if we were seeing ultrasonic junk instead of real harmonic distortion so performed an FFT spectrum analysis of 1 kHz against 10 kHz:Focusing on the blue curve which is at 10 kHz, we clearly see harmonics at multiples of it going up to 80 kHz so there is real non-linearity there.The 1 kHz tone in red clearly has lower harmonic peaks, confirming what we saw in THD+N vs frequency.Next, let's compare the same using 6BZ7 tubes:Harmonics are the 1 kHz tone are not at almost the same amplitude at 10 kHz (see dominant second harmonic). No wonder then that the curve is flat. You have distortion at all frequencies at the same level.I only measure SNR using the LISST:Full range SNR is good. At 50 millivolt output, not as much:The above measurements apply to headphone output jack as well so I did not try to duplicate them. Let's instead focus on power versus distortion and noise:The LYR 2 flexes its muscle with very high power output of 488 milliwatts at 300 ohm. My minimum level is 100 milliwatt and the LYR 2 easily sails past this. This means there is ample volume with any high impedance headphone.Replacing the LISST with 6BZ7 just adds distortion starting at 1 milliwatt in low gain. However, in high gain its performance was similar to LISST. This means that the distortion we see must be due to output stage, and not the tube pre-amp.Let's try a 33 on load to stress current delivery:We have tons of power here, clocking at whopping 2.3 watts in high gain. Alas, there is a lot of distortion at that limit.Changing to 6BZ7 makes little difference:So distortion mechanism is definitely the output stage.Measuring intermodulation distortion, this time plotting that against *output* power gives us:Sorry, ran out of time to run the same test with real tubes but you can predict it based on previous IMD versus distortion graph.Output impedance using the LISST which should be the same as tubes was a low 2.6 ohm:Channel imbalance was very good:The control doesn't lose its mind until you get 60 dB of attenuation.My backlog of equipment to be tested is insane so I did not have time for rigorous listening test. I fired up the LYR 2 with 6BZ7 tube in high gain using Sennheiser HD650 headphones. Power level and hence authority was impressive. I could easily clear out any cobwebs in my ears without even going to max volume. The sound though, seemed a bit "grungy" (yes, that is a technical term -- see Amir's dictionary of made up subjective terms). Turning up the volume seemed to make it worse.I switched to LISST tubes and that was a relief. I had the same amount of power but now what was there was very clean.When used with LISST solid state tube replacements, the Schiit LYR 2 provides thundering performance which should impress anyone coming form no headphone amplifier or a more anemic one (which would be most of the market out there). Power is the #1 determinant of headphone performance and the LYR 2 delivers.The tube option which is the reason for existence of this unit, makes no sense to me. It only adds "bad" distortion both in measurements and informal listening tests.Given how hot the unit runs, I would steer you toward JDS Labs Atom but the feel of that unit is not in the same class as the LYR 2. The Drop THX AAA 789 has the build quality but availability is poor. If you can pick up a LYR 2 with LISST tubes, it will be a reasonable alternative.OverallNot recommended with tubes however.-------As always, questions, comments, recommendations, etc. are welcome.I always write about unreasonable complaints from my pink panthers in my reviews. But their latest bit is actually a good cause: the whole gang wants to go to Africa to get to know their "roots." I think it is a good idea for them to know their true identity. Such a trip is very expensive so please donate generously using: