Cayin HA-6A vs SPL Phonitor se

Short answer

More power: the Cayin HA-6A, with 3.00 W into 32 Ω; the SPL Phonitor se has 1.00 W. The Cayin HA-6A drives 1 headphone to 100 dB that the SPL Phonitor se cannot (Symphonium Titan).
Hiss with sensitive IEMs: no headphone here hisses audibly on one and not on the other.
Price: the Cayin HA-6A costs $200 more; what that buys on these numbers is set out further down, under What the price difference buys.

Both are desktop amplifiers, $1800 against $1600.

The Cayin HA-6A reaches 100 dB on 567 of the 567 models here, the SPL Phonitor se on 566.

Side by side

Every published figure, next to each other

Specification	Cayin HA-6A	SPL Phonitor se
Power into 32Ω	3.0 W	1.0 W
Power into 150Ω	1.5 W	3.1 W
Power into 300Ω	900 mW	4.2 W
Power into 600Ω	450 mW	2.1 W
Output impedance	2 Ω unverified	0.18 Ω
Output noise	25 µV unverified	5.48 µV
Price	$1800	$1600
Headphones it reaches 100 dB on out of 567	567	566

How solid these numbers are

Where each power figure comes from

Load	Cayin HA-6A	SPL Phonitor se
32 Ω	Unverified	Published
150 Ω	Unverified	Derived
300 Ω	Unverified	Derived
600 Ω	Unverified	Derived

Cayin HA-6A publishes no electrical specification at all. That is true of 10 of the 280 sources here, and the figures in that column come from independent measurement rather than from a maker document — which is not worse, but it is not the same thing, and it cannot be checked against anything the maker will stand behind.

The SPL Phonitor se column does stand on a power rating its maker printed, at one of these four loads at least. Reading the two straight across sets one kind of claim against another, and nobody has written down the conditions of both side by side.

What the labels mean.

What separates them

The headphones that tell them apart

1 headphone reaches 100 dB on the Cayin HA-6A but not on the SPL Phonitor se — Symphonium Titan.

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

On real headphones

Headroom and hiss on 8 models, both sources

Headroom is at a 100 dB SPL peak.

The widest gap on the list is the Beyerdynamic DT 1990 Pro (250Ω): SPL Phonitor se has +39 dB of headroom there against +32 dB. 7 dB is about 4.9 times the power, which matters for peaks rather than for how loud the music sits.

The hiss columns are empty for Cayin HA-6A because that maker publishes no output noise figure.

Headphone	Impedance	Needs	Cayin HA-6A headroom	SPL Phonitor se headroom	Cayin HA-6A hiss	SPL Phonitor se hiss
Shure SE846	9 Ω	0.04 mW	+43 dB	+38 dB	not published	29 dB
Campfire Audio Andromeda 2020	9 Ω	4.0 mW	+23 dB	+18 dB	not published	9 dB
Audeze LCD-2 Classic	70 Ω	0.79 mW	+34 dB	+33 dB	not published	7 dB
Beyerdynamic DT 1990 Pro (250Ω)	250 Ω	0.63 mW	+32 dB	+39 dB	not published	3 dB
HiFiMAN HE400se	25 Ω	7.9 mW	+25 dB	+20 dB	not published	2 dB
Audio-Technica ATH-R70X	470 Ω	1.6 mW	+26 dB	+32 dB	not published	-4 dB
Sennheiser HD 600	300 Ω	6.6 mW	+21 dB	+28 dB	not published	-8 dB
HiFiMAN Susvara	60 Ω	50 mW	+16 dB	+15 dB	not published	-10 dB

What the price difference buys

The gap in dollars, against the gap in numbers

The Cayin HA-6A costs $200 more than the SPL Phonitor se. Out of the 567 models here, that difference buys 1 more model driven to 100 dB.

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.

Each has a page of its own with a full headphone list and the provenance of every figure — worth opening here, because Cayin HA-6A has published no electrical specification at all and everything above comes from independent measurement: Cayin HA-6A and SPL Phonitor se.