DAC-less dedicated headphone amps aren't exactly at the height of their popularity these last several years, most of us now looking for single-chassis DAC/amp combos. Also, relative to the total market, plug-in-the-wall desktop-size headphone amps seem to me to have taken a back seat in popularity to more portable gear, like portable DAC/amp combos and premium digital audio players. Only a few companies seem able to successfully buck these trends, and next Monday we may have the emergence of another: Massdrop. Next Monday (August 14) Massdrop is going to "drop" a plug-in-the-wall desktop size, DAC-less headphone amp--a tube / solid state hybrid one--called the Massdrop x Alex Cavalli Tube Hybrid Amp (CTH). I've had a pre-production CTH for just a couple of days, and it's beautifully made, versatile, and, most importantly has gorgeous sound on tap--the CTH sounds every bit a Cavalli amp in very early listening. What does a Cavalli amp sound like? In my experience, you don't buy a Cavalli amp for a sound that's ruthless, dry, or lean. In my experiences with amps Alex Cavalli has designed, I'd say you go for a Cavalli amp when you want tonal richness, perhaps a touch of warmth, but somehow without sacrificing the ability to resolve like a high-end amp should. Cavalli Audio's $4000 Liquid Gold, a fully-balanced flagship beast of an amp (which we did a Head-Fi TV episode about some years back) remains one of my reference amps for driving low- to mid-sensitivity headphones, especially top-notch planar magnetic headphones. If your tastes favor a leaner, drier sound, where a sense of incisiveness is one of the prevailing characteristics (which some do prefer, and there's nothing wrong with that), I would generalize that perhaps Cavalli's amps won't be for you. If the "CTH" name sounds familiar, that's because the Massdrop x Alex Cavalli CTH is based on the legendary DIY tube hybrid amp designed by Alex Cavalli that was called the Compact Tube Hybrid (CTH). This new Massdrop x Alex Cavalli CTH is a revision of the original CTH circuit. For this latest version, Alex Cavalli drew from his years of product development experience at Cavalli Audio to refine and modify the original circuit. Also, as this latest version is a desktop-sized amp, it's not quite so "compact," so the "C" in CTH now stands for "Cavalli." I'll have more to say about this amp after I've had more listening time and more headphones used with it. Again, the Massdrop x Alex Cavalli CTH just arrived a couple of days ago, so my time with it has been limited. So far, I have mostly used the Sennheiser HD800S with the CTH, and it drives the HD 800S beautifully, with a richness of tone through the bass and mids, and with treble clarity and smoothness well beyond what I'd expect at the price. Oh, the price? $249.99 with free U.S. shipping. That kind of pricing coupled with sound like this, that's what bucks trends. Again, I'll have more to say about it, but you can see the drop announcement for the Massdrop x Alex Cavalli CTH at the following link: https://www.massdrop.com/buy/massdrop-x-alex-cavalli-cth-tube-hybrid-amp Also, I know a couple/few other Head-Fi'ers have spent a lot more time listening to the Massdrop x Alex Cavalli CTH than I have and will be posting their reviews, so watch this thread. 2017-08-11 18:37 EDT: By the way, when the Massdrop x Alex Cavalli CTH arrived, I happened to have another DAC/amp on the test bench doing measurements. So I quickly swapped the CTH in to get some quick measures on the Audio Precision APx555. (Above) Frequency response from 20Hz to 20kHz. (I'll post one later that extends higher, as a later measurement showed it flat to >200kHz.) (dBrA = 2V) (Above) Frequency response deviation from 20Hz to 20kHz. (Again, deviation was just as flat out to >200kHz.) (Above) THD+N (total harmonic distortion + noise) is very good, with slightly higher levels in the right channel. (Above) This THD ratio graph shows that there's just a touch more noise in the right channel (based on the previous THD+N graph). (Above) Crosstalk measurements are good, with slightly better performance with the left channel. (Above) Intermodulation distortion (IMD) - CCIF Some quick notes on these preliminary measurements: Our Massdrop x Alex Cavalli CTH unit is pre-production, and Massdrop expects production units to be even better (built to tighter tolerances), which would be a nice bonus as this unit already measures quite well for a tube hybrid in my opinion. We used a 300Ω load. I believe Massdrop's specs use loads of 45Ω and 50Ω. Massdrop's CTH specifications (unless otherwise specified) use a 1V output (with volume knob maxed out). These preliminary measurements were done with the CTH at maximum volume, but with the input set by the Audio Precision APx555 to generate 2V at the amp's output.