Pathos InPol2 MkII Tube Hybrid Integrated Amplifier

A completely balanced, dual-mono hybrid amp with Pathos' InPol technology offering high class-A output with exceptional damping. The MkII offers more power, a better PSU, and DAC-card support

Pathos brings its celebrated InPol technology to this dual-mono beauty that is designed and manufactured in Vicenza, Italy. From the stunning 'Pathos'-shaped heatsinks to the padouk wood front panel and the red capacitors reminiscent of velocity stacks, the InPol2 oozes Italian style and grace. It's not all style though, there is tremendous audio substance too, with Pathos' distinctive sound that makes notes seem to shimmer out of the very air. 

The MkII builds on the well-known original InPol2, with the goal to supply more power at 4 ohms, and, consequently, sport more bias current. The power supply for the power amp stage has been upgraded to a traditional linear unit that is built in a dual-mono configuration with a separate transformer and rectifier bridge per channel, and two huge smoothing capacitors per channel.

The MkII can now integrate with Pathos' highly acclaimed HiDac Mk2 DAC card.

What is InPol?

When you listen to music, you’re not just hearing notes—you’re experiencing emotion. That’s the promise of Pathos’ revolutionary InPol technology: a design created to deliver all of that emotion.

Traditional amplifier designs force a compromise between the warmth of tubes and the control of solid-state. InPol (short for Inseguitore Pompa Lineare, or Linear Pump Tracker) erases that compromise. It’s a patented, fully balanced, class-A topology where a single triode stage handles all voltage amplification—and maintains 100% of its sonic signature—while the InPol circuit delivers the current gain needed to drive even the most demanding speakers effortlessly.

Features of InPol

1. Pure Class-A with No Distortion
InPol doesn’t dilute or "correct" the tube signal with negative feedback or transistor interference. Instead, it uses a specially designed current amplifier that mirrors the exact character of the tube stage, with zero phase shift or tonal coloration. The result? The harmonic beauty and liquidity of tubes, with the authority and grip of solid state.

2. Emotionally Engaging Sound
There’s a reason Pathos fans describe InPol amps as “addictive.” Music flows with natural presence, dimensionality, and richness—an emotional connection that standard designs just can’t replicate. Voices are human, strings are alive, and the soundstage breathes.

3. Exclusive, Patented Technology
Only Pathos builds amplifiers like this. The InPol circuit is a patented innovation, handcrafted in Italy and unavailable from any other brand. This isn’t another copycat design—it’s a true original for those who want something extraordinary.

4. The Best of Both Worlds
Tube magic meets muscle. The warmth and finesse of tubes drive the musical expression, while the InPol stage delivers the speed, control, and punch that brings complex music to life. It’s a marriage of passion and precision.

5. Class-A with Efficiency
Traditional class-A amps waste enormous energy as heat. InPol’s design cleverly maximizes thermal and electrical efficiency, delivering the full benefits of class-A operation with far fewer compromises—proving you can have purity and performance in one stunning machine.

This technology allows an increase in the theoretical output in pure class-A from 25% up to 50% together with a low output impedance which is fundamental for the damping factor, and further improved by the double InPoL.

The Inpol2 amplifier is true balanced in a dual-mono configuration, offering 45 W of class-A power. It has a high bandwidth and zero feedback. 

In-House Manufacturing and Design

From the wood panel to the PCBs to the chassis, everything at Pathos is either manufactured in-house or sourced from the Vicenza area. 

For example, to make the wood front panel, Pathos buys an entire padouk tree trunk, which is cut into planks in-house, and the final pieces are hand-polished by the son of the Pathos owner himself.

The panel may not contribute to the sound, but this approach says everything about the great sonics you do hear. Having control of the entire manufacturing process from start to finish means that the Pathos InPol2 is the very best amp it can possibly be at its price-point. These are the very best amps Kevin has heard, and it is Pathos that he has picked for his reference system at home. 

The Return of Tradition

As mentioned, the InPoL2 MkII moves from the previous switching power supply to a dual-mono linear power supply, so beloved by audiophiles. It continues to offer 45 W at 8 Ω, and now offers 20% more power at 4 Ω. The increased bias current is supported by bigger heatsinks. 

The fully dual mono power supply has two linear, shielded toroidal transformers (one per channel), with each channel getting separate rectifier bridges, and two 22 mF capacitors. This increase means a gain in musicality, transparency, body, and detail, especially in the bass region.

Also in keeping with high-end tradition, the volume control uses fully balanced attenuators, with relays that select high-quality precision resistors. 

An Optional DAC

In a nod to modern technology, the InPoL2 MkII can accommodate the optional HiDac Mk2 card, which adds processing to the digital inputs already present on the rear panel. There are two USB audio inputs, one coax, and one optical, allowing the InPol2 to form the heart of a multi-input digital system. The HiDac Mk2 board’s converter is state-of-the-art and guarantees high-fidelity reproduction.

Specifications

Type: Integrated stereo amplifier based on INPOL technology, operating in pure class A

Power Output (8 Ohm, 4 Ohm): 45 W, 75 W

Gain (Balanced, Unbalanced): 26 dB, 32 dB

Input Impedance (Balanced, Unbalanced): 20 kOhm, 42 kOhm

Inputs: 4 x RCA, 2 x balanced XLR

Outputs: 1 x XLR pre-amplifier / subwoofer, 2 x speaker outputs per channel

Dimensions (WHD): 16.5" x 21.8" x 8"

Weight: 83.7 lb. (38 kg)