The core is Pathos's patented InPoL circuit, a MOSFET follower with a voltage gain of about one and high current gain, biased in pure class A and run without global negative feedback. Pathos says the design lifts theoretical class A efficiency from 25 to 50 percent, and the Legacy uses two InPoL stages per channel in a bridged, fully balanced layout. Voltage gain comes from valves in a totem pole arrangement, two Tung-Sol ECC803 and one Sovtek 6H30 per channel. The dual mono build gives each channel its own power toroid, the largest Pathos has made, plus a separate toroid for the valve supply, with an inductive and capacitive filter per channel taken from the Adrenalin and InPower monoblocs. Rated output is 2 x 100 W into 8 ohm, frequency response runs from 2 Hz to 100 kHz within 0.5 dB, and THD is 0.02 percent at 1 W. Gain is 31 dB unbalanced and 25 dB balanced. Volume is a 100-step passive resistor ladder switched by relays, with Neutrik and WBT connectors.
How it sounds
The class A output stage and valve voltage gain give a full, rounded tonal balance, while the large supply keeps sudden dynamic swings from compressing. Played at high level, the room kept its transparency and scale, with small shifts in intensity still audible inside loud passages of live and orchestral recordings.
1 component
- Integrated amplifiers
InPoL Legacy
InPoL (Linear Pump Follower) was created to develop an amplification stage without feedback, with limited distortion and offers 2 x 100 W (at 8 Ohm) of power.