iBasso DC04 Pro: power output and what it will drive

The iBasso DC04 Pro is a USB dongle at $119. It delivers 125 mW into 32Ω and 13 mW into 300Ω, which ranks it 191 of 280 for raw power among the sources in this database.

Measured at 100 dB SPL it has comfortable headroom on 505 of the 567 dynamic and planar headphones catalogued here, enough but not generous on 48, only marginal on 8 and not enough power for 6. The balanced version of the DC03 Pro.

The manufacturer publishes a maximum output of 2.0 V but no power rating at any load. Every figure above is therefore a ceiling: the real output into a low impedance will be lower, possibly much lower.

The balanced output is rated separately: 281 mW into 32Ω through the 4.4mm jack.

Derivation holds output voltage steady between and beyond the published loads rather than output power, because that is what an amplifier actually does. The full method is written up here.

The output noise shown above did not turn up in any manufacturer document during this check. It is carried over from the material this database was first built from, and is marked unverified rather than quietly presented as sourced.

Source: ibasso.com, bloomaudio.com, linsoul.com.

Ordered from easiest to hardest to drive. Headroom is measured at 100 dB SPL, which is louder than almost anyone listens — a small negative number means the source still plays loud, just without reserve for peaks.

These figures come from each manufacturer's own sensitivity rating. A handful of planars — the HiFiMAN Susvara and the Abyss AB-1266 in particular — are widely reported to need far more than their published sensitivity implies, so treat a bare pass on those as optimistic rather than settled.

At 2.5 µV of output noise, here is where that noise lands in the five most revealing in-ears in the database.

That noise figure has not been traced to a document from the maker, so the levels below are as good as the number they start from.

This one hisses. With the most sensitive in-ears in the database its own noise lands around 29 dB SPL, which you will hear between tracks and in quiet passages.

At 0.2Ω output impedance this source satisfies the one-eighth rule with every headphone in the database, down to the 3Ω in-ears. Nothing here will have its frequency response shaped by the source.

The rule is a rule of thumb, not physics: a source impedance below one eighth of the headphone's keeps the interaction under about 1 dB. The checker works it out for any pair.

Of the 280 sources here, 2 do everything the iBasso DC04 Pro 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 KA5 at $99, against this one’s $119 — $20 less.

The cheaper one also publishes a noise figure, which the iBasso DC04 Pro does not — so on the paperwork it is ahead, not merely level.

This counts a headphone output and nothing else. Inputs, converters, microphone preamps, balanced outputs, the volume control, the case and the warranty are all outside it, and any of them can be the reason to buy the dearer box. What the count does say is that the three numbers a maker can be held to do not separate them.

Worked out in advance against its closest rivals: vs Astell&Kern HC3 · vs FiiO KA13 · vs FiiO KA15 · vs Hidizs S9 Pro · vs iBasso DC-Elite · vs iBasso DC03 Pro. Each of those pages lists the headphones that tell the two apart.

Or put any two side by side in the source comparison tool, or run your own headphones through the amplifier matcher. Or see every iBasso source in the database, and how much of what this site says about them came from iBasso’s own documents.