PhatLab Sassy II
Hybrid Headphone Amplifier
Ever since the debut of Sassy in 2015, everyone is astonished by its energetic performance accompanied by rich and warm sound of valves. Sassy can handle most planar magnetic and high impedance headphones by its uniquely designed tensionless hybrid topology. But there are requests from enthusiasts who hope to enjoy same sound quality and compactness with their favorite earphones. Introducing the Sassy ll, born on the expectation of many enthusiasts and beyond.
Functionally, Sassy II is equipped with a gain switch compared with Sassy. It is easy to implement gain switch in an OpAmp topology by simply changing the feedback ratios. However, it also changes the transient characteristics of amplifier that leads to sound quality changes.
On the contrary, it is not easy to add gain switch in Sassy's full discrete and zero global feedback topology. It took our engineering team months of trial and error to find the perfect solution. The mechanical switch is outside the signal path to ensure no deterioration of signal integrity and S/N ratio. We have achieved the same sound quality between two gain settings. Considering the large difference in sensitivity between general headphone and earphone, we have chosen a -10dB for low gain mode. By lowering the gain, the noise floor is also 10dB lower and there is no trace of audible noise even with most sensitive earphones.
The improvement of Sassy II is not just plain and simple functional change. The whole physical layout and signal paths was scrutinized and reorganized. The key components were revisited for cleaner and sensational sound quality. The output stage is redesigned to cope with heavier load. The noise floor is generally below -110dB and sound quality is purer even with the most sensitive earphones.
There is always tradeoff in one way or another when we improve a good design. However, we broke the rule in Sassy II. We are proud to say Sassy II has surpass Sassy from measurable electrical parameters and sound quality.
10 Hz – 100 kHz
180 mW + 180 mW (300 ohm)
1000 mW + 1000 mW (30 ohm)
30 ohm – 600 ohm
5V/1A via micro USB port
Operation time (on battery)
Approx. 10 hours (depends on headphone impedance)
Charging time (>1A supply)
Approx. 3 hours
119 mm x 93 mm x 23 mm