Pathos InPol Ear Reference Headphone Amplifier

A class-A hybrid with two Electro-Harmonix 6922's and Pathos' InPol circuit

InPol Ear is a pure class-A integrated headphone amplifier, with a fully balanced latest generation double InPol. It features two balanced and one unbalanced output and allows the addition of the HiDac Mk2 converter. The balanced output offers 10 W into 16 Ohm, and the single-ended, 6 W into 16 Ohm.

InPol (Inseguitore Pompa Lineare - Linear Pump Follower) is a Pathos patented system that allows for much greater output in pure Class A. This fully balanced circuit design uses a single solid-state component in follower configuration, with a high-current gain and voltage gain together. Think of the directness of SET with the control and damping of solid-state. InPol technology allows the tube input stage to effectively drive your speakers with no further amplification. 

An optional HiDac Mk2 converter offers a high-quality onboard DAC with digital inputs. 

The InPol Ear has Pathos' eye-catching (and highly effective) logo-shaped heatsinks, and comes in a range of center panel options.

"The only thing I regret is not having bought this amplifier 3-4 years ago!!"

Read the detailed, unsolicited customer reviews below. This amp is truly beloved, and always steals the show at our tables at CanJam or RMAF or Axpona. If you're not able to visit us, look out for the next show we're attending and bring your favorite headphones to listen to this Italian beauty!

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.

Specifications

Type: Reference stereo integrated amplifier for headphones. Pure Class A double INPOL technology

Output Power (Unbalanced, Balanced)
32 Ω: 3 W, 10 W
50 Ω: 1.9 W, 6.4 W
120 Ω: 800 mW, 2.7 W
300 Ω: 320 mW, 1 W
600 Ω: 160 mW, 533 mW

Tube Type: 2 x 6922 Electro-Harmonix

Output Impedance (Unbalanced, Balanced): 0.45 Ohm, 0.9 Ohm

Frequency Response: 2 Hz – 200 kHz ± 0.5 db

Input Sensitivity: 2.2 V RMS

Input Impedance: 100 kOhm

Output Polarity: Selectable by remote control

Volume Regulator: 2 x Burr Brown PGA2310 (180 steps 0.5 dB)

Max Input Voltage: 4.4 V RMS
Max Output Voltage (Unbalanced, Balanced): 10 V RMS, 20 V RMS

Preamplifier Gain: 9 db

Outputs: 1 x balanced XLR, 1 x RCA

Connections
Analog Line Inputs: 1 x balanced XLR, 4 x RCA 
Digital Inputs (Optional HiDac Mk2 board required): 1 x USB B, 1 x S/PDIF coaxial, 1 x S/PDIF optical
Outputs: 1 x pre out RCA (pre-output phase can be selected), 1 x pre out balanced XLR, 1 x 6.3 mm headphone, 2 x 4 pin XLR

Power Consumption: 110 W

Dimensions (WHD): 14.56" x 7" x 11" 

Weight:  27.5 lb. (12.5 kg)