Does the Schiit Valhalla 2 drive the Sennheiser HD 660S?

Computed from measured specifications · target SPL 110 dB · load 300 Ω

Ample OTL-compatible pairing

The Schiit Valhalla 2 drives the Sennheiser HD 660S with ample headroom (~22.5 dB headroom at 300 ohms; needs ~4.5 mW, delivers 800 mW). This OTL tube amp suits the headphone's impedance (217 Ω) — a classically compatible pairing for high-output-impedance tube sources.

Headroom
22.5 dB
Required (110 dB SPL)
4.5 mW
Delivered (@ 300 Ω)
800 mW
Required voltage
0.99 Vrms

Power Headroom

Headroom: 22.5 dB 0 · target 22.5 dB below target marginal adequate ample -14 dB +10 +20 +36 dB

Scale shows dB headroom above the 4.5 mW required to reach 110 dB SPL. Amp delivers 800 mW at 300 Ω (+22.5 dB above target).

Sennheiser HD 660S Dynamic · over-ear
Impedance (rated) 150 Ω
Impedance (measured) Source: reference-audio-analyzer.pro/en/r… 216.75 Ω measured
Sensitivity (rated) 104.0 dB/mW
Sensitivity (measured) 103.45 dB/mW measured
Driver Dynamic
Spec basis Measured
Measured by Reference Audio Analyzer (https://reference-audio-analyzer.pro/en/report/hp/sennheiser-hd-660s.php) · Source ↗
Schiit Valhalla 2 Desktop Tube · Single Ended
Output impedance manufacturer 14.0 Ω
Power @ 50 Ω 180 mW
Power @ 300 Ω 800 mW
Power @ 600 Ω 450 mW
Power source Manufacturer
Schiit Valhalla 2 manufacturer spec (Audiophonics retailer, citing Schiit official): 180/800/450 mW at 50/300/600 Ω. OTL/hybrid topology: more power into 300 Ω than 50 Ω (normal for OTL). Output impedance 14 Ω (hi-gain) / 3.5 Ω (lo-gain) from Schiit PDF manual and Schiit Europe. Using 14 Ω as worst-case for damping check. · Source ↗
Impedance compatibility

This OTL tube amp's high output impedance (14 Ω) is a good match for the Sennheiser HD 660S's 216 Ω impedance. The impedance ratio (15.5×) falls within the recommended range for high-output-impedance tube sources — a classically well-matched pairing.

Where to buy

Schiit Valhalla 2 on Amazon ↗ Sennheiser HD 660S on Amazon ↗

Disclosure: links above are Amazon affiliate links. As an Amazon Associate this site earns from qualifying purchases — at no extra cost to you. Affiliate commissions do not influence verdicts; all analysis is computed independently from the data.

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Schiit Asgard 3 Ample 21.2 dB
Topping L30 Ample 17.9 dB
Topping A90 Ample 17.4 dB
iFi Zen DAC V2 Adequate 9.0 dB
Apple USB-C to 3.5mm Insufficient -1.4 dB

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AKG K240 Studio Adequate 3.6 dB
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