Усилители для наушников — Schiit Audio VALHALLA 3

The Valhalla 3 is the third version of the all-tube headphone amplifier that Schiit Audio first launched in 2010 as its second product ever, at USD 499. Schiit calls it a fully modern tube amp - an OTL/OCL design with no output transformer or coupling capacitors between tubes and headphones. Ideas proven in Folkvangr, an earlier 10-tube special edition amp, were carried into this smaller desktop chassis, and apart from the tube complement it shares nothing with Valhalla 2.

Key specs that matter

With the impedance multiplier engaged the amp delivers 750 mW RMS per channel into 32 ohms, and without it 250 mW into 300 ohms, both rated at 10% THD. At 1 V RMS into 300 ohms THD+N stays under 0.05% on low gain and under 0.2% on high gain, with CCIF IMD below 0.05% and 0.25%. SNR is above 110 dB on low gain and above 95 dB on high gain, A-weighted and referenced to 2 V RMS. Crosstalk is better than -75 dB from 20 Hz to 20 kHz into 300 ohms, and response holds within 0.05 dB over the audio band. Gain is 1.25x, 6x or 10x, with output impedance of 25, 40 and 60 ohms in the low gain, high gain and no-feedback modes. Input impedance is 50 kohm and the preamp output stays under 200 ohms. The case measures about 229 x 152 x 51 mm, about 83 mm tall with tubes fitted, weighs about 3.2 kg and draws 27 W.

Engineering and use context

Each channel uses one 6N1P dual triode at the input and one 6N6P dual triode at the output in an all-triode, noninverting circuit with one voltage gain stage and a WCF output stage. Input tubes can be swapped for 6DJ8, E88CC, 6922, 6BZ7 and similar types, provided total heater current stays under 2.7 A. The linear supply combines an internal 48 VA transformer, a discrete regulated 200 V tube rail, +/-100 V output rails with capacitance multipliers and +/-12 V rails for the multiplier and oversight circuits. A DC servo and an analog computer style protection system, with no microprocessor involved, watch for DC and mute the output. The impedance multiplier makes the tubes see a higher load while they stay wired to the jack, so the distortion profile does not change. Assembly takes place in San Antonio, and the 5-year warranty excludes tubes, which get 90 days.

Pairing

Schiit states that directly coupled tubes suit high-impedance headphones best, and that the multiplier opens the amp to most other models but not to very low-efficiency ones. On low gain most IEMs work, though very sensitive pairs may reveal a noise floor. The 6.35 mm jack is single-ended, and the preamp outputs pass through the tube stage and switch off when headphones are plugged in. Case and tubes run very hot and need a ventilated spot.

Alternatives

The Schiit Midgard, listed at USD 219, is a lower-priced headphone amp from the same catalogue.