Chord Mojo 2 vs FiiO Q15

Both are portable amplifiers, $650 against $440. This page puts them side by side on the only three things a maker can be held to — power, output impedance and noise — and then asks the question that actually matters: which headphones do they treat differently?

The FiiO Q15 reaches 100 dB on 567 of the 567 models here, the Chord Mojo 2 on 566.

A figure marked not published is missing from the maker’s own material, which is not the same as being good or bad. Where one of these two publishes a number and the other does not, the comparison on that axis cannot be made at all — and saying so is more useful than guessing.

Both makers publish a power rating, which is less common than the table above makes it look: of the 280 sources here, 209 publish a figure at at least one load and only 2 publish one at all four. Chord Mojo 2 publishes at 300 Ω; FiiO Q15 at 32 Ω and at 300 Ω. Every other row is worked out from those — between two published loads, or beyond them holding voltage constant, which understates rather than flatters.

So the two columns are not equally firm row by row: at 32 Ω only the FiiO Q15 figure is the maker’s own. On those rows the derived number is the one to doubt first.

What each of these labels means, and why a derived figure is still worth printing, is set out in how this data was built.

1 headphone reaches 100 dB on the FiiO Q15 but not on the Chord Mojo 2 — Symphonium Titan.

15 headphones are left alone by the Chord Mojo 2 under the one-eighth rule but coloured by the FiiO Q15 (64 Audio Nio, 64 Audio Volur, Campfire Audio Andromeda 2023, 12 more).

7 headphones stay below the audible-hiss threshold on the Chord Mojo 2 but cross it on the FiiO Q15 (AFUL Performer 8, Campfire Audio Chimera, Dunu SA6 MKII, 4 more).

566 of the 567 models here reach 100 dB on both. That is a power count and nothing more; whether either source suits a given headphone also depends on the two lines above.

The counts above say how many models the two treat differently. This says by how much. The same 8 headphones appear on every page of this kind, ordered from the easiest to drive to the hardest, so a row can be read across pages as well as across columns. Headroom is at a 100 dB SPL peak.

The widest gap on the list is the Campfire Audio Andromeda 2020: FiiO Q15 has +20 dB of headroom there against +17 dB. 4 dB is about 2.3 times the power, which matters for peaks rather than for how loud the music sits.

Hiss is this source’s own noise, in decibels SPL, in that headphone — not a rating. Below about 20 dB SPL it is under the threshold of hearing in a quiet room; a negative figure means it is far below it.

The Chord Mojo 2 costs $210 more than the FiiO Q15. Out of the 567 models here, that difference buys 15 more models left alone under the one-eighth rule and 7 more models kept below the audible-hiss threshold.

It does not run one way only: the cheaper FiiO Q15 drives one model to 100 dB that the Chord Mojo 2 does not, which is the part worth checking against your own headphones before paying the difference.

Everything in this paragraph counts only figures the two makers published. An advantage on an axis one of them leaves blank cannot be counted, and is not counted — how often that happens is its own page.

Each has a page of its own with every power figure traced to what the maker published and a full headphone list: Chord Mojo 2 and FiiO Q15. Or put either against your own headphones in the source comparison tool.