This is the first tube based portable headphone amplifier I’ve had the pleasure of reviewing. The Phatlab Sassy II looks somewhat similar to other products in the same class but does seem to be significantly more robust. Parts of the housing are cast and machined and that results in a nice finish, The precise assembly coupled with the rounded off design elements provides a wonderful in-hand feel. At 275 grams it straddles the middle ground of feeling substantial without the notion of carrying around a lead balloon.
Turn the large and comfortable power-volume knob and you are greeted with some degree of ringing in your headphones as the unit powers on and warms up. In my case, most of my listening was done with Final Audio Sonorous IV ( S IV) headphones. The S IV’s are 8 ohm over the ear headphones and are very easy to drive without an amplifier. Despite this, when plugged into the sassy, the sound reached new levels of high – bass was punchier, the soundstage opened up and warmth and dynamics were tremendous.
I’ve had the original Sassy on hand to compare and the Sassy II has a different internal layout than the original. Externally, the primary differences include a slightly higher than flush window that gives you a view into those glowing orange tubes and the addition of a ‘Gain’ switch on the outside. The Gain switch allows for a little bit more listening flexibility by making it easier to listen a greater variety of music sources. Internally, Phatlab claims the physical layout and signal paths have been changed from the original – what you will notice is a slightly smoother, sweeter sound. Voices are warmer and more airy compared to the original.
The Phatlab Sassy II is definitely an amp for those that enjoy the virtues of a Single-Ended Triode (SET) (vacuum tube) amp in a portable form, with a strong emphasis on portable. I say portable because I happily listen to my $60 mini Bravo Audio desktop SET on a daily basis that approximates 90% of the quality of the sound I hear through the Sassy II. Alas, that amp is permanently plugged in and contains no power supply to make it portable enough to keep listening while I grab a cup of coffee from the Kitchen. The batteries on the Sassy II can make it through 3-4 hours of blissful untethered listening. When the on-board batteries diminish the sound starts distorting badly above 40% volume – a recharge fixes the problem. Unfortunately, neither the original nor the Sassy II let you know when you’ve reached that low battery threshold and the music starts distorting – the low batter indicator remained firmly unlit- Hardly what you want to see in this price range. I used the unit primarily while seated at a table or desk. I noticed that any slight contact with a solid surface (during handling) sent waves of ringing through the headphones. While in my pocket, walking around, I did not experience any of that. Ironically it seems more sensitive when placed on a desktop!?!
I also tried my Echobox Audio Traveler earbuds with the combo of the Phatlab Sassy II and the Dragonfly Red. Once again I was enveloped in that old school tube warmth. The music sounded more spacious, less clinical without being overly bright and tiring. Justin B’s voice on the Despacito remix was remarkably airier and bass bounced like I was listening to sound from giant 70’s speakers powered by a class A amp at my favorite record store. Removing the Sassy II from the line sapped the music of warm dynamism and that old school sexy sound filter.
I love the warm tube sound that comes out of the amp, and the amp is definitely capable of driving headphones to bring out their full amplified potential. Listening to rock, rap, rock, R&B and alternative tunes, the gain in dynamic punch is palpable. For those wishing for that old school sexy tube sound in a portable package, you will not be disappointed.