Schiit Valhalla 3 vs Topping A90 Discrete

Short answer

More power: the Topping A90 Discrete, with 2.00 W into 32 Ω; the Schiit Valhalla 3 has 750 mW. The Topping A90 Discrete drives 1 headphone to 100 dB that the Schiit Valhalla 3 cannot (Symphonium Titan).
Quieter with sensitive IEMs: the Topping A90 Discrete. 102 headphones stay below audible hiss on it but not on the Schiit Valhalla 3 (64 Audio Fourte, 64 Audio Nio, 64 Audio U12t, 99 more).
Output impedance: 535 headphones are left alone by the Topping A90 Discrete under the one-eighth rule but coloured by the Schiit Valhalla 3 (64 Audio Aspire 1, 64 Audio Fourte, 64 Audio Nio, 532 more).
Price: the Topping A90 Discrete costs $100 more; what that buys on these numbers is set out further down, under What the price difference buys.

Both are desktop amplifiers, $499 against $599.

The Topping A90 Discrete reaches 100 dB on 567 of the 567 models here, the Schiit Valhalla 3 on 566.

Specification	Schiit Valhalla 3	Topping A90 Discrete
Power into 32Ω	750 mW	2.0 W
Power into 150Ω	286 mW	480 mW
Power into 300Ω	250 mW	250 mW
Power into 600Ω	125 mW	125 mW
Output impedance	25 Ω	0.1 Ω
Output noise	6.32 µV	0.2 µV
Price	$499	$599
Headphones it reaches 100 dB on out of 567	566	567

Specification

Schiit Valhalla 3

Topping A90 Discrete

Power into 32Ω

750 mW

2.0 W

Power into 150Ω

286 mW

480 mW

Power into 300Ω

250 mW

Power into 600Ω

125 mW

Output impedance

25 Ω

0.1 Ω

Output noise

6.32 µV

0.2 µV

Price

$499

$599

Headphones it reaches 100 dB on
out of 567

566

567

The 4.4 mm or XLR socket, rated on its own

Balanced	Schiit Valhalla 3	Topping A90 Discrete
Socket	no separate rating	XLR4 + 4.4mm
Power into 32Ω	—	6.7 W
Power into 300Ω	—	1.0 W
Output impedance	—	0.2 Ω
Output noise	—	0.2 µV
Headphones it reaches 100 dB on out of 567	—	567

Only the Topping A90 Discrete has a separate balanced rating from its maker; through it, it reaches 100 dB on 567 of the 567 models here. The Schiit Valhalla 3 may still have a balanced socket — its spec sheet simply gives no figure for one, so there is nothing to put beside it.

Where each power figure comes from

Load	Schiit Valhalla 3	Topping A90 Discrete
32 Ω	Published	Published
150 Ω	Derived	Derived
300 Ω	Published	Published
600 Ω	Derived	Derived

Both makers publish a power rating. Schiit Valhalla 3 publishes at 32 Ω and at 300 Ω; Topping A90 Discrete at 32 Ω and at 300 Ω. The other rows are worked out from those.

The two publish at the same loads, which is the one case where the rows of this table can be read straight across.

What the labels mean.

The headphones that tell them apart

1 headphone reaches 100 dB on the Topping A90 Discrete but not on the Schiit Valhalla 3 — Symphonium Titan.

535 headphones are left alone by the Topping A90 Discrete under the one-eighth rule but coloured by the Schiit Valhalla 3 (64 Audio Aspire 1, 64 Audio Fourte, 64 Audio Nio, 532 more).

102 headphones stay below the audible-hiss threshold on the Topping A90 Discrete but cross it on the Schiit Valhalla 3 (64 Audio Fourte, 64 Audio Nio, 64 Audio U12t, 99 more).

566 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 Shure SE846: Topping A90 Discrete has +47 dB of headroom there against +37 dB. 9 dB is about 8.8 times the power, which matters for peaks rather than for how loud the music sits.

Hiss below about 20 dB SPL is inaudible in a quiet room.

Headphone	Impedance	Needs	Schiit Valhalla 3 headroom	Topping A90 Discrete headroom	Schiit Valhalla 3 hiss	Topping A90 Discrete hiss
Shure SE846	9 Ω	0.04 mW	+37 dB damping	+47 dB	30 dB	0 dB
Campfire Audio Andromeda 2020	9 Ω	4.0 mW	+17 dB damping	+27 dB	10 dB	-20 dB
Audeze LCD-2 Classic	70 Ω	0.79 mW	+27 dB damping	+31 dB	9 dB	-21 dB
Beyerdynamic DT 1990 Pro (250Ω)	250 Ω	0.63 mW	+26 dB	+27 dB	4 dB	-26 dB
HiFiMAN HE400se	25 Ω	7.9 mW	+19 dB damping	+25 dB	3 dB	-27 dB
Audio-Technica ATH-R70X	470 Ω	1.6 mW	+20 dB	+20 dB	-3 dB	-33 dB
Sennheiser HD 600	300 Ω	6.6 mW	+16 dB	+16 dB	-7 dB	-37 dB
HiFiMAN Susvara	60 Ω	50 mW	+10 dB damping	+14 dB	-9 dB	-39 dB

The gap in dollars, against the gap in numbers

The Topping A90 Discrete costs $100 more than the Schiit Valhalla 3. Out of the 567 models here, that difference buys 1 more model driven to 100 dB, 535 more models left alone under the one-eighth rule and 102 more models kept below the audible-hiss threshold.

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.