Усилители для наушников — Schiit Audio MJOLNIR

The Mjolnir listed here is the third generation, sold by Schiit Audio as Mjolnir 3 at USD 1,199 and described by the company as a Class A headphone amp and preamp. Schiit calls it the most extreme desktop product it has built. Earlier Mjolnirs used a circlotron-style circuit, one of them with tubes, while this version is an entirely new design that keeps only the 100 V front end idea from the first model.

Key specs that matter

From the balanced 4-pin XLR jack the amp delivers 2 W RMS per channel into 32 ohms and 1 W into 300 ohms, with THD under 0.015% at 4 V RMS into 300 ohms, IMD under 0.02% CCIF, SNR above 110 dB A-weighted, crosstalk better than 90 dB and output impedance below 0.25 ohm. The 6.35 mm single-ended jack gives 1 W into 32 ohms and 500 mW into 300 ohms, THD under 0.025% at 2 V RMS, SNR above 98 dB and output impedance under 0.13 ohm. Response is flat within 0.01 dB from 20 Hz to 20 kHz and falls 3 dB at 2 Hz and 700 kHz. Input impedance is 50 kohm. Gain is 2x or 8x from XLR inputs and 1x or 4x from RCA inputs. The chassis measures about 406 x 203 x 51 mm, weighs about 7.3 kg and draws about 50 W.

Engineering and use context

The gain stage, called Equipoise, is a complementary-pair discrete balanced differential circuit running zero feedback, with the signal kept balanced from input through a 4-gang volume pot to the output. A switch selects single-ended Class A, where a fixed current source biases the output stage, or push-pull Class A for more power, and a second switch adds overall feedback. Gain changes through input-stage degeneration, so it stays independent of feedback. Each channel has its own 48 VA transformer, choke, discrete regulation, a high-voltage front end rail and more than 20,000 uF of filtering. Two heatsinks borrowed from the Gjallarhorn speaker amp carry 32 bipolar output devices rated at 10 A, 16 per channel. There is no DAC, no microprocessor and no motorized pot, and the case runs hot by design. Inputs are relay switched, and chassis, transformers and boards come from California or Nevada, with assembly in San Antonio under a 5-year warranty.

Pairing

Schiit aims the balanced output at difficult headphones and advises against IEMs. A DAC with XLR outputs uses the fully balanced path, while the switchable balanced and single-ended line outputs turn the Mjolnir into a preamplifier feeding active monitors or a separate power amplifier.

Alternatives

The Schiit Lyr 5, listed at USD 799, is a smaller headphone amp from the same catalogue.