Does the Schiit Fulla 4 drive the Sennheiser HD 650?

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

Adequate

The Schiit Fulla 4 adequately drives the Sennheiser HD 650 with limited margin (~6.4 dB headroom at 300 ohms; needs ~9.2 mW, delivers 40 mW).

Headroom
6.4 dB
Required (110 dB SPL)
9.2 mW
Delivered (@ 300 Ω)
40 mW
Required voltage
1.78 Vrms

Power Headroom

Headroom: 6.4 dB 0 · target 6.4 dB below target marginal adequate ample -14 dB +10 +20 +36 dB

Scale shows dB headroom above the 9.2 mW required to reach 110 dB SPL. Amp delivers 40 mW at 300 Ω (+6.4 dB above target).

Sennheiser HD 650 Dynamic · over-ear
Impedance (rated) 300 Ω
Impedance (measured) Source: reference-audio-analyzer.pro/en/r… 344.9 Ω measured
Sensitivity (rated) 97.77 dB/mW
Sensitivity (measured) 100.35 dB/mW measured
Driver Dynamic
Spec basis Measured
Measured by Reference Audio Analyzer (https://reference-audio-analyzer.pro/en/report/hp/sennheiser-hd-650.php) · Source ↗
Schiit Fulla 4 Dac Amp · Single Ended
Output impedance manufacturer 0.5 Ω
Power @ 16 Ω 300 mW
Power @ 32 Ω 200 mW
Power @ 50 Ω 150 mW
Power @ 300 Ω 40 mW
Power @ 600 Ω 20 mW *est.
Power source Manufacturer
* 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.
Schiit Fulla 4 manufacturer spec: 300/200/150/40 mW at 16/32/50/300 Ω. NOTE: prior project fixture used 400/300/220/40 — those figures match the Fulla 3 or an earlier revision; updated to Fulla 4 (current product). Output impedance from Schiit spec. · Source ↗

Where to buy

Schiit Fulla 4 on Amazon ↗ Sennheiser HD 650 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.

AmplifierHeadroom
Schiit Lyr 3 Ample 19.9 dB
Schiit Valhalla 2 Ample 19.4 dB
JDS Labs Atom Amp 2 Ample 14.9 dB
Topping L30 Ample 14.8 dB
iFi Zen DAC V2 Adequate 5.9 dB
Apple USB-C to 3.5mm Insufficient -4.5 dB

See all amplifiers for the Sennheiser HD 650 →

HeadphoneHeadroom
Grado SR80x Ample 18.3 dB
AKG K371 Ample 17.8 dB
Beyerdynamic DT 770 Pro 80 Adequate 8.0 dB
HiFiMan Arya Adequate 8.0 dB
Beyerdynamic DT 770 Pro 250 Marginal 0.5 dB
Beyerdynamic DT 990 Pro Insufficient -0.6 dB

See all headphones for the Schiit Fulla 4 →