Mix-and-Match Fun
Apologies in advance, but this section is going to be less formal and more just my general impressions from trying the various amp and DAC combinations. No blind A/B-ing here, just me sitting down and switching cables back and forth as fast as I can to see if I can hear any differences.
Magni VS Asgard
First, let's get the easy part out of the way, the amps. I used a couple y-splitters to connect a DAC to both amps at once and level matched them by ear. I made sure that the splitter wasn't interfering with the sound first (more on this later) and then did some fast and easy testing. Since both amps were hooked up at once all I had to do was switch which amp the LCD-2s were plugged into at any point during a song and see if I could hear any differences.
And my conclusion is...(pause for dramatic effect)...as far as I can tell, at any volume I would normally listen to (or a bit above), I can hear no difference at all between the Magni and Asgard.
I tested this using both the Modi and Bifrost and both amps accurately amplified the slightly different sound signatures that they received from the two different DACs. So yes, ultimately this comparison came down to the DACs, which is where the difference is.
Modi VS Bifrost USB
According to my notes, I was able to more easily tell the DACs apart when using the Asgard. Since when I was testing the amps I couldn't tell them apart I'll chalk this up to the fact that when I was testing the DACs I was having to switch RCA cables each time, which likely made it harder to consistently remember and hear differences. I was initially planning on running both DACs into an amp using my y-splitters and switching outputs on the computer so only one would be active at once (and I could switch almost instantly in the middle of a song, which would have been hugely useful). However, when I tried this the Bifrost became muffled and the Modi very etched; no idea what exactly was going on, but as soon as I unplugged one of them the other started acting normally (even though the other wasn't outputting anything), so I was stuck switching RCA cables each time instead (yay).
With the Magni as the amp I had a hard time switching cables fast enough to come to any significant conclusion, so the following information is all from using the Asgard (and from what I can tell from comparing the amps directly should be equally applicable to the Magni, but I wasn't able to directly hear it on it).
In general the Modi VS Bifrost matches my impressions of the M&M stack compared to the B&A stack. The Modi has slightly more treble and a little bit of digital etch / glare / harshness compared to the Bifrost, which is just slightly smoother in the treble. Midrange and bass are fine on both and close enough that I could hear no differences between the two. Unlike when comparing the two stacks, I think it now sounds to me that the Bifrost is slightly more detailed, but it's more of a general feeling since as before I have yet to manage to pick out a single detail that I could or couldn't hear on one of the DACs.
I want to emphasize that the overall difference between these two is very small, if you're using Bifrost exclusively over USB I'd say the Modi easily gets you at least 90% of the way there for less than 1/4 of the price. And yes, that's a pretty arbitrary number that I probably put way too much thought into (I was mainly hesitating between 90 and 95% though, if that says anything).
The biggest problem that I've had comparing the two is that I'll focus on some aspect of the treble on the Modi, thinking I've found a noticeable difference, and then I go back to the Bifrost and find that it's almost identical. I believe if I could make myself just listen to my music and not focus on little details then I'd probably be equally enjoying myself with either, but for now I'm in over-analytical mode so I keep picking apart my songs instead.
And yes, I realize I'm using the word slightly was too often, but it really needs to be emphasized that the difference is very small. The Modi is not painfully harsh and the Bifrost isn't muffled, they are just very minorly different.
