Pros: releaxed yet capable treble, not overly warm/lush, timbre and neutrality, price, build quality,
Cons: excessive heat, diminishing returns,
After upgrading to the Valhalla, I thought I'd give it a review while comparing the lower end Magni that I upgraded from. Keep in mind these are all subjective thoughts, what may be a con for me may be a pro for you based on your preferences.
Non sound impressions: Build quality, as always, is excellent with Schiit. I can't find a single thing wrong with how it was constructed, it's solid, and even though it has a pretty compact size, it weighs a lot more than you would think. Compared to the Magni, it runs much, much hotter, but that is expected from a class A tube amplifier. The potentiometer works better on the Valhalla, it has less channel imbalance at lower volumes and is more precise than the Magni's potentiometer. The Magni's high gain seems to make the potentiometer almost useless, especially with low impedance headphones.
Bass: I can't notice any difference in the bass, they are both equal in impact and extension.
Midrange: The Valhalla adds a little more "meat" to the music and harshness is smoothed over. For example, Electric Guitars sound fuller, more laid back, and richer. The Magni sounds a bit thinner and brighter with the Electric guitar.
Treble: The Valhalla has less emphasis on sibilance and treble, however, the treble is still well extended and is there when needed, it doesn't sound overly warm or lush like a stereotypical tube amplifier. Cymbals and hi-hats still have a good sense of air and dominance, but the Magni renders them with a sharper, brighter tone. If you have been reading other reviews, the general consensus is that the Valhalla is actually quite bright for a tube amp, I agree. The Magni in comparison is a bit brighter, sharper, and more uncontrolled in the treble. However, the Magni can be much more exciting because of this, the downside is that it is more fatiguing and less forgiving of lower quality sources.
Soundstage: I don't notice much of a difference at all versus the Magni. The Valhalla sounds just a touch wider, deeper, and less in your head.
Song tests: (Source is a Schiit Modi, 320KB MP3s or FLACs, and a Sennheiser HD600)
Avenged Sevenfold, God Hates Us, Rock
Valhalla: Neutral and flatter. The Valhalla has more realistic timbre on the instrumentation versus the Magni.
Magni: Brighter and more colored. The Magni has less realistic timbre on the guitars and drums, but, it is much more exciting. The guitars and drums are thinner and have more of a "pop/snap." The vocals, while more sibilant and sharper, are more exciting.
Winner: None, tie. Do you prefer accuracy or an exciting sound?
Flying Lotus, Table Tennis (Feat.Laura Darlington), Electronic
Valhalla: Even though I was able to download this in a lossy format, this song isn't mastered too well, the Valhalla has less sibilance and everything is more laid back and lightly smoothed over with less peaks in the treble.
Magni: Sibilance is more present, the Magni is not forgiving of the recording. The guitar at the end is a bit sharper with quicker decay, the tennis balls and respirator in the background are more prominent. Treble gets a bit peaky.
Winner: Valhalla, much more smoother and forgiving.
Miles Davis, So What, Jazz
Valhalla: Towards the start, the drums on the right had less air and weren't as prominent on the Valhalla. When the trumpet abruptly starts at 1:29, the Valhalla sounded less sharp and didn't have as much glare. Good timbre on all the instruments as well. Once the trumpet goes crazy again at 3:25 on the left, the Valhalla once again sounds smoother, less sharp, and easier on the ears.
Magni: Towards the start, the drums on the right had a bit more air and sounded a bit more dominant and in your face. When the trumpet abruptly starts at 1:29, the Magni
initially renders it with a sharper tone. Timbre is alright, but the Valhalla is ahead by a hair. Once the trumpet starts up at 3:25, the Magni again rendered it with a sharper than natural tone.
Winner: Valhalla, better timbre and more controlled.
Snnop Dogg and The Doors, Riders on the Storm, Hip-hop/rap
Valhalla: The clapping in the beat is less prominent and has a slower decay (Fades away slower). Less sibilance and sharpness, sounds less in your head, but not by much.
Magni: The clapping in the beat is more prominent and has a quicker decay (Faded away quicker). The Magni has slightly more sibilance and sounds more in your head, but again, not by much.
Winner: Valhalla, more resolving in the soundstage and smoother.
A quick breakdown.
Bass impact/extension: Valhalla=Magni
Treble quantity: Valhalla<Magni
Soundstage Depth/Width: Valhalla>Magni
Detail:Valhalla=Magni (It can be argued that the Magni's treble exaggeration leads to fake detail perception, so I'm marking this as a tie.)
That about sums up my thoughts between the two amps. I must emphasize that the difference between the two is minimal, most of the differences I noticed was with critical listening and A/B testing. The reason why I only have four songs in the comparison is because in most songs, I really couldn't pinpoint much of a significant difference, other than "it sounds slightly less bright." The Valhalla is a diminishing return and it is not that much better than the Magni, in fact, on some songs it sounds even worse. I enjoyed the Magni with metal and rock, it had a more exciting and involving presentation, but, for the most part, the extra treble was unwelcome in most of my music. When I listened to lower quality music, I appreciated the Valhallas more forgiving nature. I also preferred the Valhalla for jazz, classical, and instrumentals for its more realistic timbre and pleasant tonality.