SSL 12: power output and what it will drive

The SSL 12 is an audio interface at $599. It delivers 1.2 W into 32Ω and 126 mW into 300Ω, which ranks it 71 of 280 for raw power among the sources in this database.

Measured at 100 dB SPL it has comfortable headroom on 561 of the 567 dynamic and planar headphones catalogued here, enough but not generous on 5 and only marginal on 1. The maker publishes a maximum output voltage but no power figure at any load, so every number here is an upper bound rather than a rating. Output noise is not published, so the hiss estimate cannot be run.

The manufacturer publishes a maximum output of 6.153 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.

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.

Source: support.solidstatelogic.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.

The manufacturer does not publish an output noise figure for this source, so the hiss estimate that runs on every other page here cannot be run on this one. Rather than substitute a plausible number, this page leaves the question open.

If you know the noise figure from a measurement you trust, the hiss calculator takes it directly and tells you where that noise lands in your own in-ears.

At 1Ω output impedance, the one-eighth rule says this source suits headphones of 8.0Ω and above. 15 of the 567 models here fall below that. Most of them are multi-driver in-ears, and the mismatch tilts the frequency response audibly rather than subtly.

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, 27 do everything the SSL 12 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 Schiit Magni Heresy at $99, against this one’s $599 — $500 less, and a desktop amplifier rather than an audio interface.

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 Arturia AudioFuse Rev2 · vs Audient EVO 16 · vs Audient iD24 · vs Audient iD44 MkII · vs Audient NERO · vs Focusrite Scarlett 18i20 4th gen · vs Roland Rubix44 · vs SSL 2 MkII · vs SSL 2 Plus MkII. 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 SSL source in the database, and how much of what this site says about them came from SSL’s own documents.