Does the Darkvoice 336SE drive the Fostex T50RP Mk3?

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

Verdict

Adequate

The Darkvoice Darkvoice 336SE adequately drives the Fostex T50RP Mk3 with limited margin (~3.1 dB headroom at 300 ohms; needs ~123.0 mW, delivers 250 mW). Note: this OTL tube amp's high output impedance (100 Ω) interacts strongly with this low-impedance (54 Ω) headphone, which can audibly alter its tonal balance. OTL tube amps are best paired with high-impedance (250 Ω+) headphones; this is a less ideal match.

Headroom
3.1 dB
Required (110 dB SPL)
123.0 mW
Delivered (@ 300 Ω)
250 mW
Required voltage
2.57 Vrms

Power Headroom

Headroom: 3.1 dB 0 · target 3.1 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 250 mW at 300 Ω (+3.1 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 ↗
Darkvoice 336SE Desktop Tube · Single Ended
Output impedance assumed 100.0 Ω estimated
Power @ 300 Ω 250 mW
Power @ 600 Ω 125 mW *est.
Power source Estimated 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.
OTL tube amp using 6N5P output tubes. Manufacturer page (Apos, analogmetric) states only 'Power handling capacity: 1 W' with no load specification. Power figure of 250 mW @ 300 Ω is a conservative estimate based on OTL topology similar to the Bottlehead Crack; treat as approximate. Output impedance of 100 Ω is estimated from OTL/6N5P tube topology — manufacturer does not publish this figure. 600 Ω derived from 300 Ω. · Source ↗
Impedance caution

This OTL tube amp's output impedance (100 Ω) is high relative to this headphone's 53 Ω impedance (ratio 0.5×). OTL tube amps are best paired with headphones ≥ 250 Ω; this combination may cause audible tonal coloration.

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.

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

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