Benchmark HPA4 vs Burson Soloist 3X GT

Short answer

Power: about the same. The Benchmark HPA4 has 3.35 W into 32 Ω, the Burson Soloist 3X GT 4.00 W (balanced: 3.35 W and 8.00 W). Both drive 567 of the 567 non-electrostatic headphones here to 100 dB, so on that test the difference changes nothing.
Hiss with sensitive IEMs: no headphone here hisses audibly on one and not on the other.
Output impedance: 1 headphone is left alone by the Benchmark HPA4 under the one-eighth rule but coloured by the Burson Soloist 3X GT (Symphonium Titan).
Price: the Benchmark HPA4 costs $700 more; what that buys on these numbers is set out further down, under What the price difference buys.

Both are desktop amplifiers, $3499 against $2799.

On raw power they are level: each reaches 100 dB on 567 of the 567 non-electrostatic models here.

Specification	Benchmark HPA4	Burson Soloist 3X GT
Power into 32Ω	3.4 W	4.0 W
Power into 150Ω	829 mW	650 mW
Power into 300Ω	440 mW	320 mW
Power into 600Ω	220 mW	160 mW
Output impedance	<0.1 Ω	0.5 Ω
Output noise	2.45 µV	1.5 µV unverified
Price	$3499	$2799
Headphones it reaches 100 dB on out of 567	567	567

Specification

Benchmark HPA4

Burson Soloist 3X GT

Power into 32Ω

3.4 W

4.0 W

Power into 150Ω

829 mW

650 mW

Power into 300Ω

440 mW

320 mW

Power into 600Ω

220 mW

160 mW

Output impedance

<0.1 Ω

0.5 Ω

Output noise

2.45 µV

1.5 µV unverified

Price

$3499

$2799

Headphones it reaches 100 dB on
out of 567

567

The 4.4 mm or XLR socket, rated on its own

Balanced	Benchmark HPA4	Burson Soloist 3X GT
Socket	balanced	XLR4
Power into 32Ω	3.4 W derived	8.0 W
Power into 300Ω	440 mW	640 mW
Output impedance	<0.1 Ω	0.5 Ω
Output noise	2.45 µV	not published
Headphones it reaches 100 dB on out of 567	567	567

Through the balanced sockets the two are level on the same test: each reaches 100 dB on 567 of the 567 models here. Derived figures are worked out from the loads the maker did publish.

Where each power figure comes from

Load	Benchmark HPA4	Burson Soloist 3X GT
32 Ω	Derived	Published
150 Ω	Derived	Published
300 Ω	Published	Published
600 Ω	Derived	Derived

Both makers publish a power rating. Benchmark HPA4 publishes at 300 Ω; Burson Soloist 3X GT at 32 Ω, at 150 Ω and at 300 Ω. The other rows are worked out from those.

So the two columns are not equally firm row by row: at 32 Ω and at 150 Ω only the Burson Soloist 3X GT figure is the maker’s own. On those rows the derived number is the one to doubt first.

What the labels mean.

The headphones that tell them apart

On power they are interchangeable across this whole database: there is no headphone here that one reaches 100 dB on and the other does not.

1 headphone is left alone by the Benchmark HPA4 under the one-eighth rule but coloured by the Burson Soloist 3X GT (Symphonium Titan).

567 of the 567 models here reach 100 dB on both.

Headroom and hiss on 8 models, both sources

Headroom is at a 100 dB SPL peak.

The widest gap on the list is the Sennheiser HD 600: Benchmark HPA4 has +18 dB of headroom there against +17 dB. 1 dB is about 1.4 times the power, which matters for peaks rather than for how loud the music sits.

The hiss columns are empty for Burson Soloist 3X GT because that maker publishes no output noise figure.

Headphone	Impedance	Needs	Benchmark HPA4 headroom	Burson Soloist 3X GT headroom	Benchmark HPA4 hiss	Burson Soloist 3X GT hiss
Shure SE846	9 Ω	0.04 mW	+49 dB	+48 dB	22 dB	not published
Campfire Audio Andromeda 2020	9 Ω	4.0 mW	+29 dB	+28 dB	2 dB	not published
Audeze LCD-2 Classic	70 Ω	0.79 mW	+33 dB	+35 dB	0 dB	not published
Beyerdynamic DT 1990 Pro (250Ω)	250 Ω	0.63 mW	+29 dB	+28 dB	-4 dB	not published
HiFiMAN HE400se	25 Ω	7.9 mW	+27 dB	+27 dB	-5 dB	not published
Audio-Technica ATH-R70X	470 Ω	1.6 mW	+22 dB	+21 dB	-11 dB	not published
Sennheiser HD 600	300 Ω	6.6 mW	+18 dB	+17 dB	-15 dB	not published
HiFiMAN Susvara	60 Ω	50 mW	+16 dB	+17 dB	-17 dB	not published

The gap in dollars, against the gap in numbers

The Benchmark HPA4 costs $700 more than the Burson Soloist 3X GT. Out of the 567 models here, that difference buys 1 more model left alone under the one-eighth rule.

Nothing runs the other way: there is no axis here on which the cheaper of the two does better.

Only published figures count here; blank axes are counted separately.