m-i-c-k-e-y
Headphoneus Supremus
It has been 4 years since its introduction and still no dedicated thread for this headphone amplifier.
Hoping we could share our journey/experiences with this headphone amplifier made in Italy.
Pathos Acoustics and InPol Technology
Pathos is an Italian hi-fi company founded in 1994. Led by a team of three: Gaetano Zanini, Gianni Borinato and Paolo Andriolo in Vicenza, Italy. Its innovative InPol amplifier circuit has been around for some time – in fact, the Inseguitore Pompa Lineare circuit was patented when the company was founded – but its use has mainly been in integrated amplifiers and power amplifiers for the traditional two-channel loudspeaker world. The InPol Ear represents the first time this unique hybrid circuit crosses over into the headphone world.
The term Inseguitore Pompa Lineare translates to ‘Linear Pump Follower’, and the amplifier uses a triode valve to amplify the input signal voltage, and a discrete fully-balanced Class A solid-state follower circuit designed to deliver high current and unity voltage gain to the loudspeakers. Effectively, it means the performance of that input signal and the valve driving it entirely defines the output characteristics of the solid-state amplifier powering the loudspeakers or, in the case of the InPol Ear, headphones. In theory, this should increase the efficiency of a Class A amplifier while also delivering power with optimally low output impedance. An innovation by Pathos is the ‘double InPol’ circuit, which is pretty much self-descriptive, and balanced operation throughout is handy for both input and output for any headphone amplifier.
InPol Ear Headphone Amplifier
In essence, Pathos has built an amplifier designed for loudspeakers in headphone-sized form. This means the InPol Ear has some extremely impressive specifications, like the ability to deliver up to 10W into a 32Ω balanced headphone load (unbalanced at 3W in 32Ω). The volume control is a Burr-Brown PGA3210 digital volume controller, giving precision over channel accuracy and volume setting (180 half-decibel steps). The base of the front of the InPol Ear forms the basic controls, as well as a large red LED volume display, a ¼” jack and two four-pin XLRs for balanced operation.
There are four single-ended, and one XLR line inputs, as well as a XLR and single-ended stereo output for those wanting to use the InPol Ear as a preamplifier.
Optional HiDac EVO
The optiona HiDac Evo board is an app-controlled, wired or wireless Ethernet (WiFi USB module included) streaming device complete with regular S/PDIF and USB functions. It’s built around the popular ESS Sabre 9018K2M DAC chip, so it is capable of 32bit, 384kHz resolution in PCM, and up to DSD128 through DoP connectivity over USB. The Ethernet streaming facility is driven by the InPol Ear app for Android or iOS devices. There is no Bluetooth protocol.
Design
Alongside clever circuitry, Pathos is known for its elegant industrial design, and the InPol Ear is no exception. The company has an innovative way of dealing with the necessity of heatsinks, by making them the company logo; the name is written along the sides of the amplifier in a stylish, almost Art Deco font. The front and top plates are finished in one of four finishes (three solid colours, one wood-related). At the top of the amplifier are two exposed EH 6922 double-triodes, recessed and shock-mounted in a trio of aluminium plates, and the large volume control is similarly recessed into the front of the InPol EAR.
Reviews:
Link, Link, Link, Link
MANUAL:
See this POST.
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
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)
THD: 0.1% @ 11 W
S/N Ratio: > 100 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): 11" x 14.56" x 7"
Weight: 27.5 lb (12.5 kg)
Hoping we could share our journey/experiences with this headphone amplifier made in Italy.
Pathos Acoustics and InPol Technology
Pathos is an Italian hi-fi company founded in 1994. Led by a team of three: Gaetano Zanini, Gianni Borinato and Paolo Andriolo in Vicenza, Italy. Its innovative InPol amplifier circuit has been around for some time – in fact, the Inseguitore Pompa Lineare circuit was patented when the company was founded – but its use has mainly been in integrated amplifiers and power amplifiers for the traditional two-channel loudspeaker world. The InPol Ear represents the first time this unique hybrid circuit crosses over into the headphone world.
The term Inseguitore Pompa Lineare translates to ‘Linear Pump Follower’, and the amplifier uses a triode valve to amplify the input signal voltage, and a discrete fully-balanced Class A solid-state follower circuit designed to deliver high current and unity voltage gain to the loudspeakers. Effectively, it means the performance of that input signal and the valve driving it entirely defines the output characteristics of the solid-state amplifier powering the loudspeakers or, in the case of the InPol Ear, headphones. In theory, this should increase the efficiency of a Class A amplifier while also delivering power with optimally low output impedance. An innovation by Pathos is the ‘double InPol’ circuit, which is pretty much self-descriptive, and balanced operation throughout is handy for both input and output for any headphone amplifier.

InPol Ear Headphone Amplifier
In essence, Pathos has built an amplifier designed for loudspeakers in headphone-sized form. This means the InPol Ear has some extremely impressive specifications, like the ability to deliver up to 10W into a 32Ω balanced headphone load (unbalanced at 3W in 32Ω). The volume control is a Burr-Brown PGA3210 digital volume controller, giving precision over channel accuracy and volume setting (180 half-decibel steps). The base of the front of the InPol Ear forms the basic controls, as well as a large red LED volume display, a ¼” jack and two four-pin XLRs for balanced operation.

There are four single-ended, and one XLR line inputs, as well as a XLR and single-ended stereo output for those wanting to use the InPol Ear as a preamplifier.
Optional HiDac EVO
The optiona HiDac Evo board is an app-controlled, wired or wireless Ethernet (WiFi USB module included) streaming device complete with regular S/PDIF and USB functions. It’s built around the popular ESS Sabre 9018K2M DAC chip, so it is capable of 32bit, 384kHz resolution in PCM, and up to DSD128 through DoP connectivity over USB. The Ethernet streaming facility is driven by the InPol Ear app for Android or iOS devices. There is no Bluetooth protocol.

Design
Alongside clever circuitry, Pathos is known for its elegant industrial design, and the InPol Ear is no exception. The company has an innovative way of dealing with the necessity of heatsinks, by making them the company logo; the name is written along the sides of the amplifier in a stylish, almost Art Deco font. The front and top plates are finished in one of four finishes (three solid colours, one wood-related). At the top of the amplifier are two exposed EH 6922 double-triodes, recessed and shock-mounted in a trio of aluminium plates, and the large volume control is similarly recessed into the front of the InPol EAR.

Reviews:
Link, Link, Link, Link
MANUAL:
See this POST.
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
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)
THD: 0.1% @ 11 W
S/N Ratio: > 100 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): 11" x 14.56" x 7"
Weight: 27.5 lb (12.5 kg)
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