This is a review and detailed measurements and comparison of Topping A30 and Schiit Magni 3 headphone amplifiers. I own both units and their accompanying DACs (Topping D30 and Schiit Modi 2). The review will be mostly covering the amplifiers but at the end, I will provide a snapshot comparison of both units "as stacks" with their DACs. Hey, that rhymes!The Topping A30 is available everywhere and as of this writing costs USD $110 including Prime shipping from Amazon. Schiit only sells its products direct and the Magni 3 costs $99 but then you have to pay shipping which would make the cost comparable to Topping.Both units are desktop sized as you see here stacked on top of their DACs:While the "design language" is identical between the two Topping products, as you can see in the picture, the two Schiit units have different finishes. What is that about? Did they change manufacturers for one of the units and didn't try to get color matching?A more relevant point is that on Topping products, all the controls are in front. Schiit as with most of their units, puts such things as power switch and in this case, the headphone gain control in the back. While you can learn to find them by feel, you can't tell their settings by just looking at the unit.The Topping has two headphone outputs with the 3.5 mm having an inline resistor and triple gain settings. This allows one to nicely match the demands of the headphone to the power the unit produces. There is also a high and amplifier voltage that I did not test. The unit comes with the largest linear wall wart I have ever seen on a desktop product! Luckily it has cords at both ends so you can plug it into any outlet.The Schiit has two gain settings which while not identical to Topping, they do the job.I am sure you all are interested in how they measure. I have learned that testing headphones is a bit of nightmare. With multiple gain settings, different loads to test, and position of volume control in testing, the matrix can become infinite. I am still refining what my core set of tests should be for such units. As such, you will not see every combination tested. If you want something that is not measured, time permitting, I can run more tests.Like my DAC tests, I thought it would be good to have a "dashboard" view of the units. Here, I used a 600 ohm load on them as to make them work as little as possible (using 100K load caused the Magni 3 to be erratic in one channel). I also set the units so that they are acting as a "buffer" or unity gain. In other words, they don't amplify the DAC output but rather, allow it to drive much more difficult/real headphone loads at the same output level of 1 volt. This setting provides some of the best performance I could get out of the units.First up is Schiit Magni 3:We are getting pretty good performance with Sinad (signal above distortion and noise) of almost 100 dB in one channel. The other though is trailing at 97 dB.Here is Topping A30:We see an improved SINAD of 106 dB and performance of two channels being very similar. We see though that harmonic distortion is actually much better than Schiit Magni 3. The reason SINAD is not even better is due to fair bit of mains noise. Since our hearing sensitivity is much worse in low frequencies, the THD measurement is not a fair comparison of audibility here but we go with it.Let's load these units with 300 ohms and see where we land:The slightly higher gain of Topping A30 pushes its noise floor higher than Schiit Magni 3. Fortunately it, and Schiit Magni 3 can be driven in low gain mode which lowers the noise floor more.Powerwise, the A30 runs out of juice earlier than Magni 3, producing 0.18 watt of clean power. Schiit Magni 3 produces more power of 0.33 watts but at 3X higher distortion point than Topping A30 (0.005% THD+N versus 0.001% respectively). Indeed distortion becomes dominant over noise (where the curve tilts up) in Schiit Magni 3 at lower power than Topping A30. This effect is exaggerated when we switch to 33 ohm load:The Topping A30 provides its good performance right to the limit whereas the Schiit Magni 3 starts to distort more at just 2 milliwatts. By the time Schiit Magni 3 is outproducing the Topping A30 in power, its distortion is already up at 0.1% or so which is unacceptable in my book.Schiit rates the Magni 3 at 2 watts using 32 ohm load. Mine at 1.7 watts using 33 ohm is close enough to say that is a fair rating. Topping rates the power at 32 ohm at 1.5 watts which is more optimistic than the cut off point I use.Note that due to logarithm nature of the above graphs, there are not that many measurement points at clipping. So the actual point may be slightly higher than shown there. I can run a higher resolution test but it takes much more time.Let's run an intermodulation distortion test using 50 ohm load for variety:We see that the Topping A30 has a commanding lead in distortion between 50 or so millivolts until clipping. So if that is the region of performance you use, the Topping A30 should sound cleaner.The achilles heel of Topping A30 unfortunately is its high output impedance:The impedance using the TRS connector is at 10.8 ohms which is the rated spec. The Schiit Magni 3 cleans it clocks at just 0.6 ohms. The higher output impedance of Topping A30 can modify the frequency response of your headphone (for good or bad).Finally, let's see how good channel balance is as we lower the volume in low-gain mode. First Schiit Magni 3:That's pretty good response with deviation below 0.5 dB until the absolute end.Here is how Topping A30 did using medium gain:The Topping A30 mutes the output as you get close to the end and hence the drastic cliff. So you have about 30 dB of attenuation. Here is the performance at unity gain setting:Now you can go a bit lower before muting kicks in. Overall, the deviations are less than Schiit Magni 3 until you get at the minimum level.As promised, this is a snapshot how the combo of Topping D30+A30 compare to Schiit Modi 2+Magni 3 perform. First the Topping stack:Once again we are in unit test mode but at 2 volts because that is what the DAC outputs. Here is the Schiit combo:We see almost 3X the distortion compared to Topping stack. SINAD as dropped from 97 dB to 89 dB.There is also fair bit of channel imbalance visible even on the scope graph on top left.The Topping stack is clearly the lower distortion producing of the two.For my testing here, I used my HiFiman HE400i and Sennheiser HD-650 headphones. Both units were level matched (to I think 4 volt output) and then driven with a split RCA cable from my Topping DX7s DAC. I then used the volume control on Topping to adjust listening level as needed.At low, background listening/enjoying level, both units sounded good reflecting the fidelity of the source. No difference in distortion or noise was audible.Turning up the level from medium to high, caused one of the units to get bright. Identifying that unit showed it was Magni 3. It is ever so slightly brighter which can indicate to some as more soundstage or detail -- none of which are true. The extra distortion generated by Magni 3 increases the high frequency content and hence that subjective impression. No real change was there in any other fidelity aspects no matter how much I concentrated.I then turned up the levels until the headphone cups were literally rattling.The Topping had clear audible distortion but not as much as the Schiit Magni 3. The Magni 3 had maybe 10% more headroom as far as how loud you could make it but the sound was very distorted and hence, that headroom was not usable.I could not detect any change in frequency response due to higher output impedance of Topping A30. I need to create better test scenarios to see how audible this is. And yes, the choice of above two headphones may have made this point moot.Please note that these subjective tests are NOT authoritative. While I control levels and perform the test blind, these are not rigorous tests with many trials and such. Use them as a more reliable listening test than the random nonsense you read in subjective reviews but not enough to trump the objective measurements.The picture emerging from the measurements is not clear cut. In general the Topping A30 has lower distortion but that is accompanied with much higher output impedance and lower power output.Both units provide similar enjoyment when listening to music at low to reasonably loud levels (with headphones I tested). Above that both fall apart and can't compete with likes of iFi iDSD Black Edition . I would give the nod to Topping A30 if you listen loud as I do.Both Topping A30 and Schiit Magni 3 are recommended for budget friendly choices in headphone amplifiers. Let your preferences in looks, usability, etc. guide you in your selection.-------------As always, questions, comments, recommendations, etc. are welcome.If you like this review, please consider donating funds for these types of hardware purchases using Patreon ( https://www.patreon.com/audiosciencereview ), or upgrading your membership here though Paypal ( https://audiosciencereview.com/foru...eview-and-measurements.2164/page-3#post-59054 ).