Fully Balanced/Dual Mono High Output Headphone Amplifier
The HA-507 employs a high-power analog amplifier circuit with exceptionally wide bandwidth and low distortion characteristics. It features a fully balanced/dual mono configuration with a total of four amplifier elements (left/right/positive/negative).

Originally designed to drive full-size speakers, the amplifier element is not only extremely powerful, but also capable of reproducing the texture of music with extreme subtlety. This amplifier element gives the HA-507 an exceptional headphone drive capability of 6,700mW + 6,700mW (32Ω) at balanced output, which can fully drive any headphones, including low-sensitivity, high-impedance ones, with unparalleled musicality.

When driving unbalanced headphones, the internal balanced amplifiers are switched to an active-ground configuration. The unbalanced headphone output provides an exceptionally wide soundstage by actively driving the signal ground level to zero voltage.

Drives All Types of Headphones to the Maximum
Two balanced outputs (Neutrik XLR 4-pin and 4.4mm Pentaconn) and two unbalanced outputs (6.3mm and 3.5mm) are provided. Gain can be switched in three levels (High/Mid/Low) to match the headphones being used.

Can Be Used as a Separate Power Amplifier for the Headphones
For the ultimate head-fi who wants a separate pre/power amplifier system for headphones, the HA-507 can be used as a separate headphone power amplifier by pairing it with high-end external preamplifiers. Preamp pass-through mode can be activated by a switch on the rear panel.

This feature is also useful for listeners who already own an ultra-high-end preamp for their speaker system and prefer a single preamp configuration for both speaker/headphone listening.
Even in this preamp pass-through mode, the gain and L/R balance functions are enabled for ease of use.

Analog audio inputs
Balanced – XLR × 2 pairs
Input impedance – 40kΩ
Maximum input signal voltage – 6Vrms
Unbalanced – RCA × 2 pairs
Input impedance – 20kΩ
Maximum input signal voltage – 3Vrms

Analog audio outputs
Balanced – XLR × 1 pair
Output impedance – 50Ω
Maximum output voltage – 7Vrms
Unbalanced – RCA × 1 pair
Output impedance – 100Ω
Maximum output voltage – 3.5Vrms

Headphone outputs
Balanced – 4-pin XLR × 1 / 4.4mm 5-pole stereo jack (Pentaconn) × 1
Rated output – 6,700mW + 6,700mW (into 32Ω) / 4,200mW + 4,200mW (into 100Ω) n/ 1,800mW + 1,800mW (into 300Ω) / 950mW + 950mW (into 600Ω)
Unbalanced – 6.3mm (¼”) stereo jack × 1 / 3.5mm (&frac1/8;”) stereo mini jack × 1
Applicable load impedance – 16 to 600Ω

General
Power supply – AC 220 230V, 50/60Hz (Europe), AC 120V, 60Hz (USA/Canada)
Power consumption – 30W (0.3W in standby)
Oveall dimensions- (W × H × D)290 × 84.5 × 243.9mm / 11-½” × 3-⅜” × 9-⅝” (including protrusions)
Weight – 4.6kg / 10-¼ lb

Audio performance
Frequency response – 10Hz to 150kHz (+1/–4dB)
THD + – N0.0006％ (1kHz, LPF: 20kHz)
S/N ratio – 110dB (A-weight, 1kHz