Headphones amplifiers — Lehmann Audio Linear II

The Linear II replaces the original Linear, the desktop headphone amplifier that Lehmannaudio of Cologne brought to market in 2004 and that entered a mastering studio in the same year. The company calls it the Second Generation Legend and lists it among its home headphone amplifiers, in a catalogue that also includes the Linear D, Linear USB II and Linear SE. It is built in Germany by a firm that was founded in 1988 under the name Entec.

Key specs that matter

Output reaches 400 mW into 60 ohms and 200 mW into 300 ohms. Response runs from 10 Hz at -0.3 dB to 35 kHz at -1 dB. Four gain positions of 0, 10, 18 and 20 dB are chosen with DIP switches. Total harmonic distortion stays below 0.001% at 6 mW into 300 ohms, noise sits more than 100 dB below signal at 0 dB gain, and channel separation is better than 70 dB at 10 kHz. The headphone sockets have a 5 ohm output impedance, and the input presents 47 kohms. The unit draws 10 W, measures 110 x 280 x 50 mm and weighs 1.5 kg net.

Engineering and use context

The main change over the first Linear is a new circuit board made in Low-Z copper technology, which carries the class-A output stage. Mundorf capacitors sit in both the power supply and the signal path, and the regulated supply uses a 30 VA transformer with two large reservoir capacitors. Other parts include MKT capacitors, military grade resistors and a 27 mm ALPS volume potentiometer. Lehmannaudio fits its own 3S device feet to damp mechanical vibration in the housing. Owners of older Linear-series units can have the Low-Z board retrofitted at the factory, with 3S feet offered as an extra. Finish choices are silver aluminium, black aluminium and chrome.

Pairing

Two gold-plated Neutrik headphone jacks on the front can serve two listeners at once or allow quick A/B checks between headphone models. Line-level sources connect to Teflon-insulated, gold-plated RCA inputs, and a rear pre-out lets the Linear II set the level for active loudspeakers or a power amplifier such as the Lehmannaudio Stamp, which the maker positions as a pre/power partner for its Linear. At the lowest gain setting the noise floor is lowest, which helps with sensitive in-ear monitors, and the two highest gain positions add reserve for headphones rated up to 600 ohms.

Alternatives

The Lehmannaudio Linear SE is a related home headphone amplifier from the same range, offered with a customisable housing and LED colour.