Усилители для наушников — Trafomatic Audio Head 2

The Trafomatic Audio Head 2 is a headphone amplifier using valves, doubling as a line preamplifier, built in Mladenovac, Serbia. Trafomatic describes it as its second headphone amplifier, following the Experience Head One. The circuit runs in push-pull class A, and all amplification is done by valves.

Key specs that matter

Per channel the Head 2 runs one 6N30P and one ECC88 double triode. Maximum headphone output is 2 W into 50 ohm, and the amplifier applies 3 dB of feedback. The headphone output impedance is selectable in steps of 25, 50, 100, 300 and 600 ohm. Gain is 26 dB, input sensitivity 0.5 V and input impedance 47 kohm. Bandwidth for the headphone and line outputs runs from 10 Hz at -1 dB to 80 kHz at -3 dB. Trafomatic quotes THD of 0.2 percent at 0.5 W and 1 kHz and S/N of 88 dB. Power consumption is 60 VA, with mains voltage selectable between 230 V at 50 Hz and 115 V at 60 Hz. The case measures 400 x 310 x 100 mm and weighs 10 kg. The launch price was EUR 1,900.

Engineering and use context

A proprietary output stage is fitted with two double C-core output transformers using quadfilar windings, which is what makes the range of impedance taps possible. The power supply uses multi-stage high-voltage filtering. Inputs are available on XLR and RCA, and as a preamplifier the Head 2 drives both XLR and RCA line outputs, whose source impedance is 6 ohm on RCA and 25 ohm on XLR. The valves are hand-picked, and the 6N30P has a rated life of more than 10,000 hours. Two large knobs sit on the front, and turning the left one fully clockwise switches the unit into preamplifier mode, while a toggle switch on the left side turns the power on and off. Headphones connect through a Neutrik 4-pin balanced socket or a 6.35 mm stereo jack. The case is a lacquered, curved plywood body with an aluminium grille on top, under which the valves lie horizontally, and air vents underneath let heat escape upward. Besides the standard finish the amplifier is offered in white and black, and other RAL colours can be ordered, with knobs and feet in gold or silver.

Pairing

The output taps allow the Head 2 to be matched to planar headphones of low impedance and also to high-impedance dynamic models, and the 4-pin output accepts balanced cables. In preamplifier mode it can supply a power amp or active speakers through either output type, so one unit covers both a headphone desk and a speaker system.

Alternatives

Trafomatic also made the Experience Head One, a tube headphone amplifier with 6S45P triodes, about 300 mW of output and 30, 100 and 300 ohm impedance switching.