Does the Schiit Fulla 4 drive the Fostex T50RP Mk3?

Computed from measured specifications · target SPL 110 dB · load 50 Ω

Marginal

The Schiit Fulla 4 marginally drives the Fostex T50RP Mk3; barely reaches target SPL (~0.9 dB headroom at 50 ohms; needs ~123.0 mW, delivers 150 mW).

Headroom
0.9 dB
Required (110 dB SPL)
123.0 mW
Delivered (@ 50 Ω)
150 mW
Required voltage
2.57 Vrms

Power Headroom

Headroom: 0.9 dB 0 · target 0.9 dB below target marginal adequate ample -14 dB +10 +20 +36 dB

Scale shows dB headroom above the 123.0 mW required to reach 110 dB SPL. Amp delivers 150 mW at 50 Ω (+0.9 dB above target).

Fostex T50RP Mk3 Planar · over-ear
Impedance (rated) 50 Ω
Impedance (measured) Source: reference-audio-analyzer.pro/en/r… 53.65 Ω measured
Sensitivity (rated) 91.0 dB/mW
Sensitivity (measured) 89.1 dB/mW measured
Driver Planar
Spec basis Measured
Measured by Reference Audio Analyzer (https://reference-audio-analyzer.pro/en/report/hp/fostex-t50rp-mk3.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 ↗
Planar driver note

Planar-magnetic headphones can have high current demands that are not fully captured by the power headroom model. Even with adequate headroom, some solid-state amps may struggle to deliver sufficient peak current for transient dynamics. Prefer amps rated for low-impedance planars.

Where to buy

Schiit Fulla 4 on Amazon ↗ Fostex T50RP Mk3 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 16.9 dB
JDS Labs Atom Amp 2 Ample 13.3 dB
Topping DX3 Pro+ Ample 11.7 dB
Schiit Magni Heretic Ample 11.1 dB
Little Dot MkII Insufficient -0.9 dB
Apple USB-C to 3.5mm Insufficient -6.0 dB

See all amplifiers for the Fostex T50RP Mk3 →

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 →