Roland BRIDGE CAST: power output and what it will drive

The Roland BRIDGE CAST is an audio interface at $340. It delivers 78 mW into 32Ω and 29 mW into 300Ω, which ranks it 232 of 280 for raw power among the sources in this database.

Measured at 100 dB SPL it has comfortable headroom on 490 of the 567 dynamic and planar headphones catalogued here, enough but not generous on 63, only marginal on 5 and not enough power for 9. Power is published at 32Ω, 250Ω; the rest of the table is derived from those figures. Output noise is not published, so the hiss estimate cannot be run.

What it actually puts out

TypeAudio interface
Price$340
Power into 32 Ω78 mW
Power into 150 Ω36 mW
Power into 300 Ω29 mW
Power into 600 Ω15 mW
Output impedance10 Ω
Output noisenot published
Comfortable headroom on 490 of 567 headphones (86%) · short of power on 9

Where these numbers come from

The manufacturer publishes 78 mW into 32Ω, 35 mW into 250Ω. The rest of the table is worked out from those.

Derived rows hold output voltage steady, as an amplifier does (method).

Source: roland.com.

LoadPowerStatusHow it was arrived at
32 Ω78 mWPublishedthe manufacturer publishes this figure at this exact load
150 Ω36 mWDerivedworked out between two published loads, holding output voltage linear between them
250 Ω35 mWPublishedthe manufacturer publishes this figure at this exact load
300 Ω29 mWDerivedbeyond the published loads, holding output voltage constant — which understates rather than flatters
600 Ω15 mWDerivedbeyond the published loads, holding output voltage constant — which understates rather than flatters

Against 40 well-known headphones

Easiest to hardest to drive, with headroom at a 100 dB SPL peak.

HeadphoneImpedanceSensitivityNeedsHeadroomVerdict
Shure SE8469 Ω114.0 dB/mW0.04 mW+27 dBComfortable damping
64 Audio U12t12.6 Ω108.0 dB/mW0.16 mW+23 dBComfortable damping
Shure SE21517 Ω107.0 dB/mW0.20 mW+23 dBComfortable damping
Moondrop Aria32 Ω107.1 dB/mW0.19 mW+26 dBComfortable damping
Audeze LCD-X 202120 Ω103.0 dB/mW0.50 mW+20 dBComfortable damping
Truthear Hexa20.5 Ω103.1 dB/mW0.49 mW+20 dBComfortable damping
Sennheiser IE 20018 Ω101.6 dB/mW0.69 mW+18 dBComfortable damping
Sony MDR-750663 Ω106.0 dB/mW0.25 mW+23 dBComfortable damping
Meze 99 Classics32 Ω103.0 dB/mW0.50 mW+22 dBComfortable damping
Focal Clear MG55 Ω104.0 dB/mW0.40 mW+21 dBComfortable damping
Philips SHP950032 Ω101.0 dB0.79 mW+20 dBComfortable damping
Focal Utopia80 Ω104.0 dB/mW0.40 mW+20 dBComfortable
Meze Empyrean32 Ω100.0 dB1.0 mW+19 dBComfortable damping
Campfire Audio Andromeda 20209 Ω94.0 dB4.0 mW+7 dBEnough damping
Etymotic ER2SE15 Ω96.0 dB/mW2.5 mW+12 dBComfortable damping
AKG K37132 Ω99.1 dB/mW1.2 mW+18 dBComfortable damping
Audio-Technica ATH-M50X38 Ω99.0 dB/mW1.3 mW+17 dBComfortable damping
Beyerdynamic DT 900 Pro X48 Ω100.0 dB/mW1.0 mW+18 dBComfortable damping
Audeze LCD-2 Classic70 Ω101.0 dB/mW0.79 mW+18 dBComfortable damping
Grado SR80x38 Ω98.0 dB/mW1.6 mW+16 dBComfortable damping
Sennheiser HD 560S120 Ω100.8 dB/mW0.83 mW+17 dBComfortable
HiFiMAN Edition XS18 Ω92.0 dB6.3 mW+8 dBEnough damping
HiFiMAN Arya Stealth32 Ω94.0 dB4.0 mW+13 dBComfortable damping
Dan Clark Audio AEON 2 Closed13 Ω90.0 dB/mW10 mW+5 dBEnough damping
Audeze LCD-514 Ω90.0 dB/mW10 mW+5 dBEnough damping
Beyerdynamic DT 1990 Pro (250Ω)250 Ω102.0 dB/mW0.63 mW+17 dBComfortable
HiFiMAN HE400se25 Ω91.0 dB7.9 mW+9 dBEnough damping
HiFiMAN Sundara32 Ω92.0 dB6.3 mW+11 dBComfortable damping
Dan Clark Audio Stealth23 Ω90.0 dB/mW10 mW+7 dBEnough damping
Fostex T50RP MK350 Ω92.0 dB/mW6.3 mW+10 dBEnough damping
AKG K70262 Ω92.9 dB/mW5.1 mW+10 dBEnough damping
ZMF Verite Closed300 Ω99.0 dB/mW1.3 mW+14 dBComfortable
Sennheiser HD 650300 Ω97.8 dB/mW1.7 mW+12 dBComfortable
Sennheiser HD 800S300 Ω96.8 dB/mW2.1 mW+11 dBComfortable
Beyerdynamic DT 770 Pro (250Ω)250 Ω96.0 dB2.5 mW+11 dBComfortable
Audio-Technica ATH-R70X470 Ω98.0 dB/mW1.6 mW+11 dBComfortable
ZMF Atrium300 Ω96.0 dB/mW2.5 mW+11 dBComfortable
Abyss AB-1266 Phi TC50 Ω88.0 dB/mW16 mW+6 dBEnough damping
Sennheiser HD 600300 Ω91.8 dB/mW6.6 mW+6 dBEnough
HiFiMAN Susvara60 Ω83.0 dB50 mW+0 dBMarginal damping

Will it hiss?

The manufacturer does not publish an output noise figure for this source, so there is no hiss estimate here. If you have a measured figure, the hiss calculator takes it.

Output impedance and the one-eighth rule

At 10Ω output impedance, the one-eighth rule says this source suits headphones of 80.0Ω and above. 510 of the 567 models here fall below that. That is most of the database, not a niche — 222 of them multi-driver in-ears, and the mismatch tilts the frequency response audibly rather than subtly.

Check any pair.

The cheapest thing here that does the same job

SourceTypePriceInto 300 ΩOutput impedanceOutput noise
FiiO KA11USB dongle$2922 mW0.7 Ω1.7 µV
FiiO BTR13Bluetooth receiver$5910.0 mW0.6 Ω1.0 µV
iBasso DC03 ProUSB dongle$6910 mW0.12 Ω0.9 µV

Of the 280 sources here, 46 do everything the Roland BRIDGE CAST does as a headphone output: reach 100 dB on every headphone it reaches and stay inside the one-eighth rule wherever it does. The cheapest of them is the FiiO KA11 at $29, against this one’s $340 — $311 less, and a USB dongle rather than an audio interface.

The cheaper one also publishes a noise figure, which the Roland BRIDGE CAST does not — so on the paperwork it is ahead, not merely level.

This counts the headphone output only; inputs, converters, the volume control and the build are outside it.

Other audio interfaces at a similar price

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