Burson Soloist 3X GT: power output and what it will drive

The Burson Soloist 3X GT is a desktop amplifier at $2799. It delivers 4.0 W into 32Ω and 320 mW into 300Ω, which ranks it 15 of 280 for raw power among the sources in this database.

Measured at 100 dB SPL it has comfortable headroom on 566 of the 567 dynamic and planar headphones catalogued here and enough but not generous on 1. Power is published at 16Ω, 32Ω, 100Ω, 150Ω, 300Ω; the rest of the table is derived from those figures. The published table does not sit on one curve: 1.9 W into 100Ω is 13.8 V, while 0.65 W into 150Ω is 9.9 V, and an amplifier does not lose voltage into a lighter load. That table is reproduced from dealer listings rather than a Burson document — Burson publishes only prose — so the step may be a transcription error that has been copied around. Treat the high-impedance rows as the weaker evidence.

The manufacturer publishes 5.0 W into 16Ω, 4.0 W into 32Ω, 1.9 W into 100Ω, 650 mW into 150Ω, 320 mW into 300Ω. Everything else in the table above is worked out from those figures, and this table says which is which.

The balanced output is rated separately: 8.0 W into 32Ω through the XLR4 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: bursonaudio.com, bloomaudio.com, magic-mastering.com, hifiplus.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 1.5 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 24 dB SPL, which you will hear between tracks and in quiet passages.

At 0.5Ω output impedance, the one-eighth rule says this source suits headphones of 4.0Ω and above. 1 of the 567 models here falls below that. The one model below that line is the Symphonium Titan, 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, 40 do everything the Burson Soloist 3X GT 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 $2799 — $2700 less.

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 Benchmark HPA4 · vs Bryston BHA-1 · vs Ferrum OOR · vs Holo Audio Bliss KTE · vs McIntosh MHA200 · vs SPL Phonitor xe. 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 Burson source in the database, and how much of what this site says about them came from Burson’s own documents.