Ok heres a place to comment on the Schiit Vahalla 2 headphone amp. I have had one for a few years and its a wonderful amp with HD 600’s, but has been re-designed to work with lower impedance headphones.
Frequency Response: 20Hz-20Khz, -0.1db, 7Hz-200KHz, -3dB
Maximum Power, 300 ohms: 300mW RMS per channel at less than 10% THD
Maximum Power, 600 ohms: 340mW RMS per channel at less than 10% THD
THD: < 0.02%, 20Hz-20KHz, at 1V RMS, low gain, 600 ohms
IMD: < 0.03%, CCIF at 1V RMS low gain, 600 ohms
SNR: > 98db, unweighted, referenced to 1V RMS, low gain
Crosstalk: < -71dB, 20 Hz-20KHz
Output Impedance: 14 ohms (hi gain), 3.5 ohms (lo gain)
Input Impedance: 100K ohms
Gain: 7 (16.9db) or 1.5 (3.5 db), via rear switch
Topology: All-triode, noninverting, single voltage gain stage, current source biased front end and optimized WCF output stage, DC-coupled input
Tube Complement: 6N1P dual triode input, 6N6P dual triode output, 1 each per channel. 6N1Ps rollable to 6DJ8, E88CC, 6922, 6BZ7, and similar types.
Power Supply: Two internal power transformers with over 2,000uF of filter capacitance
Power Consumption: 40W
Size: 9 x 6 x 3.25”
Weight: 7 lbs
The Vahalla 2 is still and OTL amp, but Schitt has spent a long time optimizing both the input and output topology to maximize current delivery, and to reduce output impedance. This entailed quite a few tweaks to the common-cathode front end, adding a new negative voltage rail and current source to up the overall gain, and also changes to the White cathode follower output.
2-8x lower output impedance, 8x lower distortion, 2x more current delivery, and lower noise. In simpler terms: while Valhalla was marginal-to-bad with IEMs and low-impedance headphones, Valhalla 2 is better. It’s not the be-all and end-all, but it’s now a much more well-rounded amp.
Valhalla is still going to be at its best with high-impedance headphones like the 300 ohm Sennheisers and 250-600 ohm Beyers. With up to 60V p-p output capability, it can light up high-impedance headphones.
Two gain settings via a rear switch. HI and Lo, and a rear power switch.
There is no turn on relay so you may want to wait 30 seconds or so before plugging your headphones into the unit. I have never had an issue with this with my Vahalla 2. Approx 100mv at 32 ohms and less with higher headphones, which is wear this amp still shines.