Heritage Audio O.H.M. Headphone Amplifier – A Mix Product of the Week

New York, NY (February 13, 2025)—Heritage Audio has announced the release of the O.H.M Amp, reportedly the first impedance-matching headphone amplifier. Designed to extract the full potential from any pair of headphones, the O.H.M. Amp is intended for use in studio and audiophile listening applications.

Circuitry for the O.H.M. Amp was derived from that used in Heritage Audio’s R.A.M. System 2000 and 5000 monitor controllers, employing Burr Brown op amps that deliver high fidelity and ultra-low noise.

The front panel features ¼-inch and 3.5 mm headphone outputs, and output level is controlled using an audiophile-grade Alps “Blue Velvet” potentiometer. Additional front-panel controls include an impedance switch with six settings ranging from Low (approx. 6 to 8 Ω) to 600 Ω, and a three-position input selector switch. The impedance switch can be used to match the output impedance of the O.H.M. Amp to a wide variety of headphones.

Input to the O.H.M. Amp is on the rear panel and offers the option of unbalanced RCA, balanced TRS/XLR combo jacks, or a high-quality Bluetooth receiver (codecs: APTX, APTX LL, AAC, APTX HD and SBC) with Burr Brown DAC. Built-in pass-through outputs enable multiple O.H.M. Amps to be daisy-chained, or for the O.H.M. Amp to be used as a Bluetooth receiver with DAC.

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The O.H.M. Amp is powered using an external low-noise, high-voltage power supply (30V) that maintains high dynamic range, a high signal-to-noise ratio and low harmonic distortion regardless of the headphone impedance.

The bottom of the unit features rubber feet to protect furniture, as well as a 5/8-inch threaded socket for mounting the unit on a microphone stand.