Schiit Magni Piety vs Topping L50

Short answer

More power: the Topping L50, with 2.80 W into 32 Ω; the Schiit Magni Piety has 1.00 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: cannot be compared — neither maker publishes a noise figure.
Output impedance: 1 headphone is left alone by the Topping L50 under the one-eighth rule but coloured by the Schiit Magni Piety (Symphonium Titan).
Price: the Topping L50 costs $29 more; what that buys on these numbers is set out further down, under What the price difference buys.

Both are desktop amplifiers, $200 against $229.

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

Every published figure, next to each other

Specification	Schiit Magni Piety	Topping L50
Power into 32Ω	1.0 W	2.8 W
Power into 150Ω	446 mW	933 mW
Power into 300Ω	400 mW	540 mW
Power into 600Ω	200 mW	290 mW
Output impedance	0.6 Ω	0.1 Ω
Output noise	not published	not published
Price	$200	$229
Headphones it reaches 100 dB on out of 567	567	567

Not published means the maker leaves it out, so that axis cannot be compared.

Where each power figure comes from

Load	Schiit Magni Piety	Topping L50
32 Ω	Published	Published
150 Ω	Derived	Derived
300 Ω	Published	Published
600 Ω	Published	Published

Both makers publish a power rating. Schiit Magni Piety publishes at 32 Ω, at 300 Ω and at 600 Ω; Topping L50 at 32 Ω, at 300 Ω and at 600 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

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 Topping L50 under the one-eighth rule but coloured by the Schiit Magni Piety (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 Campfire Audio Andromeda 2020: Topping L50 has +27 dB of headroom there against +22 dB. 5 dB is about 2.9 times the power, which matters for peaks rather than for how loud the music sits.

The hiss columns are empty for Schiit Magni Piety and Topping L50 because neither maker publishes no output noise figure.

Headphone	Impedance	Needs	Schiit Magni Piety headroom	Topping L50 headroom	Schiit Magni Piety hiss	Topping L50 hiss
Shure SE846	9 Ω	0.04 mW	+42 dB	+47 dB	not published	not published
Campfire Audio Andromeda 2020	9 Ω	4.0 mW	+22 dB	+27 dB	not published	not published
Audeze LCD-2 Classic	70 Ω	0.79 mW	+29 dB	+34 dB	not published	not published
Beyerdynamic DT 1990 Pro (250Ω)	250 Ω	0.63 mW	+28 dB	+30 dB	not published	not published
HiFiMAN HE400se	25 Ω	7.9 mW	+21 dB	+26 dB	not published	not published
Audio-Technica ATH-R70X	470 Ω	1.6 mW	+22 dB	+24 dB	not published	not published
Sennheiser HD 600	300 Ω	6.6 mW	+18 dB	+19 dB	not published	not published
HiFiMAN Susvara	60 Ω	50 mW	+11 dB	+16 dB	not published	not published

The gap in dollars, against the gap in numbers

The Topping L50 costs $29 more than the Schiit Magni Piety. 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.