Heritage Audio O.H.M Amp Impedance-Matching Headphone Amplifier with Bluetooth

Heritage Audio O.H.M Amp: Impedance-Matched Headphone Monitoring

The Heritage Audio O.H.M Amp is an impedance-matching headphone amplifier with a switchable output-impedance control that adapts to any pair of headphones. A headphone amplifier drives headphones with cleaner, more powerful signal than a phone or interface can, and matching the output impedance to the headphones themselves brings out their full potential. That single idea lets the same box flatter cheap earbuds and high-impedance audiophile models alike. For studios and listeners chasing the best from their headphones, it is a genuinely different kind of amp.

Impedance Matching for Any Headphones

The defining feature is the impedance switch, which sets the amp's output impedance to suit the headphones plugged in. Every set of headphones has its own impedance, and matching it improves damping, tone, and drive rather than leaving the pairing to chance. Hard-to-drive planar and high-impedance models in particular open up when the amp is matched to them. It is a level of control most headphone amps simply do not offer.

Three Selectable Inputs, Including Bluetooth

Three independently selectable sources feed the O.H.M Amp: a balanced input, a gold-plated RCA input, and a pro-quality Bluetooth receiver. The Bluetooth stage uses a Burr Brown DAC and supports aptX, aptX LL, aptX HD, AAC, and SBC codecs for high-quality wireless listening. A DAC (digital-to-analog converter) turns a streamed digital signal back into analog audio, so the wireless path stays clean. Whether the source is a console, a turntable stage, or a phone, one switch selects it.

Discrete Diamond Buffers and Burr Brown Op Amps

Inside, the O.H.M Amp uses discrete diamond buffers taken from Heritage Audio's high-end R.A.M System 2000 and 5000 monitor controllers. Paired with Burr Brown op amps for extreme fidelity and ultra-low noise, they give the amp an audiophile-grade response with whatever headphones are connected. Diamond buffers are a discrete output stage prized for driving demanding loads cleanly. That circuitry is what lets a compact amp out-muscle far larger designs.

Alps Blue Velvet Level Control

Volume runs through a sought-after Alps Blue Velvet potentiometer, an audiophile-grade component known for smooth, precise tracking. A good level pot matters because it sets how evenly the left and right channels move as you turn it down. The action here is fluid and exact, which makes fine adjustments effortless. It is the kind of detail that separates a serious headphone amp from a basic one.

Two Outputs, No Noisy Adapters

Independent 1/4-inch and 1/8-inch headphone jacks sit on the front panel, so both full-size headphones and earbuds connect directly. Skipping adapters removes a common source of noise and unreliable connections. A Thru output lets you chain several O.H.M Amps together or use the unit as a premium Bluetooth receiver feeding another device. That flexibility suits both a single listener and a small headphone setup.

External 30V Supply and Flexible Placement

A dedicated external 30V, low-noise power supply gives the amp real headroom, ensuring strong power delivery, wide dynamic range, and ultra-low distortion at any impedance. Keeping the high-voltage supply outside the chassis helps hold the signal path quiet. Rubber feet let the O.H.M Amp sit as an elegant tabletop device, while a 5/8-inch threaded hole on the bottom mounts it to any microphone stand. It fits a desk, a rack of stands, or a listening chair equally well.

Who the O.H.M Amp Is For

Mixing and mastering engineers who trust headphones, and audiophiles with a collection of hard-to-drive models, are the core audience. A producer can match the amp to studio cans for accurate monitoring, then switch to Bluetooth for relaxed listening on the same unit. Owners of high-impedance or planar headphones gain the drive those designs demand. For anyone serious about headphone sound, the O.H.M Amp is built to bring it out.