A Portable Gran Turismo Amplifier

Ever since the 2015 debut of Sassy, everyone was astonished by its energetic performance accompanied by rich and warm sound of valves. Sassy handles most planar magnetic and high impedance headphones by its uniquely designed tensionless hybrid topology. In extreme cases, Sassy may deplete its fuel due to compact power reservoir (electrical capacitance) and low biased output stage. During the development of Sassy II, we have come up with a derivative proposal to exploit the extreme potential of Sassy hybrid topology. Sassy GT is the result.

Without changing the basic topology and compactness, we revisited the design to find out the power delivery bottleneck in extreme cases. The study concluded that the two most effective factors are:

• Power reservoir, equivalent electrical capacitance, which holds the energy for instantaneous demand during highly dynamic music passages.
• Thermal stability of output stage after increasing the static biased current.
The power reservoir is doubled in Sassy GT and the output stage is covered with a thermal pad to facilitate thermal spreading and to reach thermal equilibrium. These implementations ensure dynamic performance and long term reliability. Besides the component upgrades, the vacuum tubes, JAN6418, are hand-selected among hundreds of tubes from the same batch based on the requirement of high current gain to match the newly specified high power operating point. Only 10% of tubes can pass the strict criteria.

Recommended Sassy GT Application

Just like Gran Turismo vehicle, Sassy GT consumes more power for higher driving capability. A simple comparison is; if Sassy II can run 10 hours on battery, then Sassy GT will run for 6 to 7 hours. Additionally, Sassy GT has a 3dB gain over Sassy ll. We recommend Sassy GT for audiophiles who own extremely low sensitivity headphones that demand the most from the companion amplifier.

Specifications