Does the Little Dot MkII drive the Sennheiser HD 660S?

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

Ample

The Little Dot MkII drives the Sennheiser HD 660S with ample headroom (~18.2 dB headroom at 300 ohms; needs ~4.5 mW, delivers 300 mW). Note: output impedance for this amp isn't reliably published, so the damping interaction into this 217 Ω load can't be assessed; treat low-impedance pairings with caution.

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

Power Headroom

Headroom: 18.2 dB 0 · target 18.2 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 300 mW at 300 Ω (+18.2 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 ↗
Little Dot MkII Desktop Tube · Single Ended
Output impedance assumed Not published
Power @ 32 Ω 100 mW
Power @ 120 Ω 200 mW
Power @ 300 Ω 300 mW
Power @ 600 Ω 150 mW *est.
Power source Manufacturer low confidence
* Loads marked "est." are derived from the published voltage ceiling at a lower-impedance load (V = √(P·R) → P_higher = V²/R_higher). All derivations are upward only.
Little Dot MkII SEPP OTL circuit. Power figures (100/200/300 mW at 32/120/300 Ω) appear consistently across retailer listings (Linsoul, ShenZhenAudio) citing manufacturer spec. Note unusual characteristic: more power into 300 Ω than 32 Ω — typical for OTL amps. Output impedance not published; SEPP OTL topology suggests ~20–50 Ω but no reputable non-forum measurement found. Set null; damping check flagged as indeterminate. 600 Ω derived from 300 Ω. · Source ↗
Impedance — unknown output impedance

This amp's output impedance is not reliably published, so the damping interaction into this 216 Ω headphone cannot be assessed. Treat low-impedance pairings (below ~80 Ω) with caution.

Specification confidence: low

One or more amp specifications (power output or output impedance) are estimated rather than published by the manufacturer. Treat this pairing's verdict as approximate.

Where to buy

Little Dot MkII 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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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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HeadphoneHeadroom
Sennheiser HD 560S Ample 16.7 dB
Sony MDR-7506 Ample 16.6 dB
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AKG K240 Studio Marginal 1.0 dB
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