Over the past several months I've had the great fortune to go through several really great dacs. It started with my acquisition of the Prism Lyra1, and then through some wrangling, trades, and loaners, I've also queued up:
Prism Lyra
Prism Callia
RME ADI-2 Pro
Forssell MDAC-2a
Schiit Yggdrasil
Hegel D12
Space Tech Super 24/192
(these last two I tossed in there because they happened to cross my desk around the same time)
The first few brands may be unfamiliar territory to most, but they are big players in the pro audio world. My original intention was to go through the pro stuff, but as luck would have it I meandered back into familiar hifi territory with the Yggy which I think will provide a better reference point for most here.
Now I can't pretend to be nearly as eloquent or in-depth as Torq here, but I'll do my best to present my findings with enough comparison points to be useful. Note however that I did not have the Yggy at the beginning. Most of my notes were written in the context of comparing which few dacs I had with me at the same time. Sometimes I did A/B/C switching. Sometimes I would listen to a few songs at a time. Sometimes I'd do only one dac a day and check how well my notes lined up. Sometimes I used headphones, and other times I used monitors. Why didn't I have a super strict systematic methodology for evaluation? Because I'm human and want to enjoy my time with the gear rather than obsessing (moreso than usual) over all the fiddly bits. Besides, I've already written several theses in my lifetime and have no desire to write any more. Also, I've been dragging my feet writing this thing and have spread it out over waaaaay too many weeks, so my apologies if my structure seems cobbled and if paragraphs seem to jump from one thought to another. They may have literally been written a month apart.
So now as I stare at the veritable mountain of notes I have cobbled in front of me, I find myself somewhat staggered in terms of how to produce something comprehensible. So perhaps I will start with ultra-simplified one-sentence summaries of each dac, followed by a not-quite-a-diary play by play as I went through the dacs in rotation (roughly in the order that I got them). I normally wouldn't do it this way, as I feel putting up such short word-bites at the beginning will colour how the review is read for each component. However, considering how many different pieces that I will be going through, I think having a starting point to build mental impressions upon is better than none in this case. My impressions will also be a mix of paragraph and point-form notes, because ain't nobody got time to read all my chicken scratch. I will leave out the pages and pages of tech specs too so I can focus on just sound and usage impression.
With that out of the way, here are my micro summaries for each. I will list two things that I liked, and one that I didn't (though I'm stretching on those negatives). The technical performances can be considered roughly the same as they are all fantastic dacs; you'll have to dig deeper into the review for specifics.
Prism Lyra1: musical and sweet, the most engaging, a bit too soft
Prism Callia: more muscle in the amp and more presence than Lyra, kinda pushy upper mids
RME ADI-2 Pro: super technical performance, amazing DSP options, somewhat dry
Forssell M-DAC2a: midrange warmth, superb staging, lacks extension
Schiit Yggdrasil: great cohesion, great overall resolution, yet at the same time a slight haze
A slight gap as the following two are not in the same tier as the above...
Space Tech Super 24/192: nice clarity, relaxed presentation, weak in detail/separation
Hegel D12: nothing great, nothing bad, it's just so average sounding =/
My listening evaluations via headphones were done mostly with a Hifiman HE-6, Sennheiser HD650, NuForce HEM8 and whatever else I may have had on hand. On speakers I had active monitors with Genelec 1030a, and passive with ATC SCM20. Amping duties for both headphones and passive speakers came through a Benchmark AHB2, Lab Gruppen LAB300, or Bryston B60. I also had an iFi iCAN Pro on loaner review for a while.
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Alright, so moving onto the meat of the review, let's start things off with the Prism Lyra1, Prism Callia, and RME ADI-2 Pro as these were the first three that I started working on. I started off with the Lyra1 as something that I obtained for my own personal use as it is meant as a two channel "portable" recording interface, and I'm a radio monkey who occasionally needs to record sessions and do voicework. Do I need such a fancy high-end interface for my decidedly amateur-hour needs? No, not even close, but as with all things in this hobby the neurotic need for better and fancier toys is never-ending.
Prism, for those who do not know the brand, are one of the "big" names in pro audio. There's the consumer level stuff that you can get at BestBuy, there's the "prosumer" stuff that you can get at your local music/guitar store, and then there's the actual pro stuff that you never actually looked at because they start at 4 figures and up. That's where Prism lies. They dwell heavily in the recording realm rather than the live arena, but apart from that are also particularly well known for making measurement gear (the most famous of which is the dScope; I believe our own
@atomicbob here uses one for his work) that produces numbers and graphs on all the toys that we audiophiles like to play with.
Now RME for those who don't know, much like Prism they are also one of the "big" names in pro audio. They don't make measurement gear, but do play more in the live sound realm where they are known for their rock solid stability and dependability.
Anyhow, when I first got the Lyra I had some trouble getting the drivers to install on my Windows 7 laptop (it was fine on my Windows 10 desktop). I sent an email to their customer service which sparked off a week long troubleshooting escapade, which ultimately concluded with me figuring out that it was a rather complex Windows update error causing all the issues (long story short: Windows Update needed to update the updater in order to install updates, but it couldn't because the system was out of date... yeah it's as stupid as it sounds; I feel dumber having written it). That said, Prism's customer service was amazing and beyond reproach, and I feel it is worth mentioning because they had at least three of their top guys not just walking me through the usual script but actually having me send in update logs and data dumps and screen caps, and they kept up with that for well over a week. So anyways, somewhere through that adventure I mentioned that I would eventually write up my experiences with their gear and I inquired about their Callia. After a few more emails and some paperwork, a Callia was on my way for evaluation.
With the RME it was a decidedly less adventurous route. I contacted them and mentioned that since I already had two Prism units would they be interested in having my evaluate the the ADI-2 Pro. After a few bounced emails from Germany to US to Canada and some more paperwork, another unit was on it's way. Cool.
Ok, with that preamble out of the way, let's get going with the...
Prism Lyra 1
First up, let's talk about the build quality. No it's not some super special milled-from-solid-aluminum chassis, but it's not some off the shelf hammond case either. The fit and finish is above average. All the jacks feel solid when plugging things in. On power-up you can hear the various relays inside engaging. There are LED meters on front to indicate input and output levels (both analog and digital). The main volume knob is not a traditional potentiometer but rather a simple indented rotary dial with infinite spin and LEDs to indicate volume level (29 steps?). Very handy is the press-to-mute ability of this dial, and the volume indicator will blink when muted. I also appreciate that I can adjust the level and it doesn't un-mute until I press the button again.
Important to note too is that the Lyra has a software control panel, through which you can adjust volume/mutes, but also all the various in/out hardware routing as well as your output reference levels (+4 dBu and -10 dBV). It allows for a lot of mix and match if you have both analog and digital sources. It has an optical input, usb input, and two analog inputs (for line/instrument and mic/line), and you can decide which inputs go to the analog outs, optical output, or headphone jack which is handy for your bedroom recording artist. Most readers here however will probably never use the routing options, but they are a handy feature. The mic preamp is also fantastic and miles ahead of anything I've used from the likes of prosumer brands (even with my trusty SM58, I could immediately tell the difference). But again, that probably doesn't interest the majority if you here. For those who care, Prism has an extensive online manual that's worth a look.
Unlike the main volume knob, the headphone knob *is* a regular pot that controls the output levels and there is a lot of power on tap. There is no software volume control, though you can internally mute and control which source feeds it. The pot itself is surprisingly stiff. There is lots of power on tap, though there is also a high output impedance (100 ohms). Actually, I think the gain is too high on the headphone jack overall, which limits its use for headphone nuts. Just fine for planars, but not so great for others which I'll touch upon later. Inserting headphones does not mute the analog outputs at the back.
A note on the analog outputs, the circuit contains what Prism describes as a "level-compensation bootstrapping circuit", which I assume is some sort of servo control. This allows the use of single ended adapters off the balanced outputs (TRS) and the levels will auto-shift depending what kind of connectors it detects, rather than losing half the signal like you usually do when dropping down to RCA which typically grounds the negative leg or cuts it off entirely.
Accessories with the Lyra are very basic. There's a high quality usb cable and power cord (not your typical junky ones that you'd get for a buck from ebay), and a cd with your drivers (which also act as your software control panel). Aside from the initial hiccup with the drivers, the installation and even firmware updates went off without a hitch. Just follow their online instructions (relatively simple) and you'll be fine.
Prism Callia
Build quality is roughly the same as the Lyra, though the more streamlined front makes it seem sturdier. The main volume knob is still infinite spin with LEDs to indicate level (bonus: your LED brighness is adjustable), does not have indents, but it is significantly sturdier than the Lyra which is nice. It lacks the push-to-mute feature though; and I was surprised how much I miss this.
Oddly, the pot for the headphone jack was much looser than the Lyra, and I wonder why the change. However, it does have a much better output impedance (4 ohm, which is just enough to satisfy the x8 rule with your standard 32ohm headphones) and a big advantage over the Lyra with selectable output levels via some DIP switches at the back. It has Low/Med/High output levels, and even the low setting should be enough for just about everyone. I left it on medium which was enough even for my ridiculous HE-6 which are power pigs. There is also a fourth setting which has Medium output, but also maintains the analog outputs when a headphone is plugged in (all other settings auto-mute). Max output on high setting is technically the same as the Lyra, but obviously much more available on tap with the lower output impedance.
On the back there is a set of both XLR (balanced) and RCA (single ended) outputs, so no need to fidget with adapter cables or what-have-you. For inputs you have the more standard array of usb, optical (toslink), and coax. Selection can be automatic or toggle the power button to cycle through.
Accessories are much the same as the Lyra, except it also has a flash drive containing the drivers. Amusingly, this flash drive is super slick with a metal enclosure and water/dust proof screw on cap. It's so over the top, but as part of the fit and finish of the whole product, I can appreciate it. The Callia uses the same drivers as the Lyra, but does not activate the software control panel as there is no need for it. Personally I would have liked to have the option software control over volume, but that's just me.
RME ADI-2 Pro
Coming from the Prism gear, the RME was surprisingly small at less than half the size. While lighter and smaller, it is still a solid feeling chassis. Arguably even more so, as a smaller case tends to have less give and thus feels sturdier. All the jacks likewise are solid and all the buttons and knobs have a solid and consistent feel. This is very important as all the features of the ADI-2 Pro are controlled entirely through the hardware knobs; there is no software interface. All the knobs are also buttons and are multifunctional. They are infinite spinning types, not pots.
Unlike the Prism gear, the ADI-2 Pro uses a wall-wart. Rest assured however that there is a significant amount of power supply filtering and canoodling going on inside the case to smooth everything out. If you're a putz like me with poor eyesight, you might also wonder why the barrel plug for power is so flimsy and loose... until you realize that it's actually a locking connector and it's super secure once you actually set it properly. Whoops.
Driver installation and firmware updates is relatively simple. Download some files, follow their instructions, yadda yadda. A well trained computer literate monkey could do it.
An important note on the analog outs: Do NOT use single ended adapters on the XLR outputs. Unlike the Prism boxes, RME does not have any correction circuitry here. If you wish to use single ended gear, use the pair of TS (1/4") sockets on the back which are inherently single ended. If you need to use RCA, then the stubby little 1/4" mono plug to RCA adapters can be had for literally pennies off ebay.
The RME does have inputs, but unlike the Lyra they are not mic preamps. I asked why not, and the reason they gave is because mic preamp circuits would have complicated the power supply.
A potentially important note is that the RME does tend to heat up a bit. Noticeably moreso than the Prism boxes, but it's also a lot more circuitry packed into a much smaller chassis. For most practical purposes it probably doesn't matter much, but for me personally I tried to leave it on its own rather than stacking gear on top or below it, particularly if those other boxes were also heat producers.
Now one of the huge selling features of the ADI-2 Pro is the staggering amount of options you can access from the front panel. Any other reviews you read you will find people praising the manual, and I'm no different. Seriously, just go check it out online and lose yourself in the innumerable ways you control the sound. If you are of the purist type, then just leave everything as is and put the dac into "hifi" mode (available with the latest firmware upate) and forget about the rest. Maybe just leave it on the volume screen and you can watch the meters bobble up and down with your music. For those who like to fidget, you will be greatly entertained. Just on the EQ front you have many layers of options. There's the general EQ, the treble/bass menu, and also a unique "Loudness" setting which to my knowledge is the only implementation of the loudness function done properly. That is, the amount of "loudness" applied dynamically changes with your volume level. Now that's nifty! I also enjoyed playing with dac filter settings, though at that point you're getting into the nitty gritty crazy part of this hobby. Oh and there's crossfeed; more on that later. The interface takes a little bit of getting used to. It's reasonably intuitive once you get going, but it's deep enough that you probably won't get it on the first try.
One of my favourite little interface things is that the volume has "speed" detection. If you turn the knob quickly, it will change in large increments. If you turn it slowly, it will move in very small increments. Nice touch! (pun intended) The latest firmware also let you customize keys, and one of my other favourite features is being able to switch between the front or rear balanced outputs by holding the main volume button (super handy for switching between using headphones or speakers).
Listening Impressions (DAC only): Lyra vs Callia (bonus Mimby comparison)
In general I found the DAC performance of the Lyra and Callia to be extremely close, so let me try to describe a few differences there before I do the broader Prism vs RME comparisons. But first of all, a reference point...
When I first got the Lyra, another dac I had on hand that should be a known quantity to most of you was the Schiit Modi-Multibit (aka Mimby). When I first got the Mimby, I was thrilled with it's performance. New toy syndrome and all that. After a week, I was still impressed but definitely less giddy. To help you calibrate to my ears and brainwaves, I would characterize the Mimby sound as if someone were shining a strong flashlight on top of a picture. No no, I don't mean it's bright sounding. I mean look at the picture, the light brings everything out so it's clear and visible, but... that bright light also kinda washes things out, so it's all there and there's stuff you maybe didn't notice before, but at the same time it's all there but also not sharp. Some have described it as a veil which I kinda agree with. Potayto potahto. I would say it's more like a very very mild haze.
So anyhow, going from that to the Prism was like leaving the light on, but putting on a good set of (very mild) sunglasses. All the details were there, but no longer washed out. No it's not the same thing as just having a dimmer light with the shades; work with me here. More light, but more focus because the shades bring more specific focus. Say they're polarized sunglasses if that makes you happier. The overall feeling was like I was able to see through the haze.
Mimby staging felt further away and echo-y in a way, but it had better shape and definition to each instrument. Lyra on the other had had much more air, while the Mimby felt like it was emphasizing that upper mid band too much which made it come more forward. Yeah I realize that it seems contradictory that I would describe the Mimby as both more veiled yet more upfront in the treble.
Lyra has a greater sharpness overall, like if there were a contrast knob then the Mimby is a little bit on the flab side and the Lyra is a little bit more on the pizazz side. This greater sharpness lets the Lyra brings out textures better. Reverbs in the music are cleaner rather than disappearing into the background. Random noises in the background of live recordings are no longer random noises but actually come out more clearly.
Ok so onto the Lyra vs Callia. As I mentioned earlier, these two are actually super close to each other. Nitpicking at this level really kinda takes the fun out of the listening, but these are the sacrifices we make when we love gear just as much as we love music. Sometimes.
Anyhow, while they are super super similar, I would have to give the very slight nod to the Callia in overall performance. I'm not sure if I can even fully reason it out as better implementation, or if it's simply because there's less stuff (no microphone inputs, no hardware/optical outputs, no routing, etc) to cause noise and thus a cleaner board overall. Sometimes the Callia feels lighter, sometimes it feels heavier, it's basically into placebo territory... but if you were to twist my arm I would say that the Lyra is just a smidge hazier and while airy also tends to float away. The Callia feels like it has a bit more presence and is a bit more forward in the lower treble range. This could make it feel slightly pushy, and potentially more fatiguing on poor quality recordings or low bitrate files (but if you're spending thousands of dollars on a dac and you have poor quality files, you're doing this hobby wrong).
On hi-rez is where I felt the improvements in the Callia seemed more noticeable. Lyra smoothed things out while Callia seemed to bring back some of the edge. Whether or not you like that edge though is up to your particular set of ears. I typically don't like this nebulously non-defined word called edge, but here I felt it was like just one extra tiny notch on the contrast dial like the Mimby going to the Lyra, but perhaps a quarter step past that. One other bit that I can't quite qualify is what feels like better snaps/pricision on the Callia, as if for just that instant it was more dynamic. Like a split second of more headroom.
One other advantage on paper is that Callia can handle DSD. I don't care.
Here's an interesting pickle though. I felt the Callia was actually a lot better when being fed through the Lyra's optical output and the low level details (like movement of musicians or audience background) are more perceptible. This would lead one to believe that the usb is the bottleneck, which is a possibility, although I believe the usb implementations are more or less the same on the Lyra and Callia. The Lyra does do some mathemagic on the optical output to clean things up, so that's a possibility as well. It may also just be a power supply thing, taking the usb out of the equation maybe keeps the dac portion of the Callia happier and cleaner.
Listening Impressions (DAC only): Prism vs RME
Alrighty, so with Lyra vs Callia more or less out of the way, let's look at Prism vs RME.
As it was between the Prism dacs, differences noted are incredibly minimal. So even if my words make it sound like a lot, it really isn't. Important to note is that the differences noted were at least consistent through changing amps and headphones. Through the various combinations, I found it easiest to pull out the differences with single ended connection into the Bryston B60 into my HE-6.
In general, I would say the Prism dacs produced a "deeper" sound. More guttural as it were. At the same time they also lean to the more technical side (I know it's a stereotype that most "pro" dacs sounds this way, but I'd say that's tentatively true for any of the higher level stuff). Technical doesn't necessarily mean cold or shrill sounding. More like... a marching band over a jazz band.
Now the RME takes that technical nature and pushes it further. I'm gonna use the word clinical here, as that's what it reminds me of. While the Prisms have this softer tone, the RME feels hard. Where the Prism feels centered, the RME feels more spread out (the actual note from my scribbles here is "ghosty"). Where I call the Prism airy, I call the RME sweet. The RME produces a wider stage than the Prism, but also feels slightly behind.
Texturing and layering is where I would say the RME excels. Like I can really feel and pull out each instrument from the music. But where the texturing is tight and precise, it also veers slightly to the metallic side, whereas the Callia is softer and less precise but produces a more relaxed tone.
The RME impact is super well defined with a pronounced leading edge, while the Prism rounds it out to feel fuller. Like if you've ever played a tympani, it's not the difference between a wooden and felt mallet. It's more like two felt mallets of different density, with the RME being the harder felt. Of course, changing the filters affects this (this particular note made using the SD Sharp filter; switching to the SD Slow feels much closer to the Prism sound; the NOS filter feels too soft)
One odd thing I noticed consistently with the RME was that subjectively I always felt like it was a half decibel louder. I would doublecheck with a multimeter and adjust until output levels were the same, but going back to ear then I'd want to bring the RME down a half notch. I did not notice anything like this between the Lyra and Callia, nor with the Forssell (which I'll talk about later); all the others I could play tones and level match by ear and be right on the money on the multimeter, but no so with the RME. Strange. Maybe it's something in the converters. Maybe I'd need an oscilloscope to figure things out, but who's got the time for that sort of nonsense? I'm not saying one is more right than the other, it's simply one quirk that I've noticed.
Related to that, I also find I can tell the difference when playing pink noise, but in this case the Callia is the one which feels like there's more energy up top. I was surprised by this, considering that the RME feels louder to me I was expecting pink noise to lean towards louder with the RME as well but it wasn't. I then suspected it was the filter, which could be a partial answer. When I first ran this test I had the RME on the SD Slow filter which does have a very slight rolloff up top. I switched the filter to SD Sharp and that brought the tone of the RME pink noise up... but the Callia still seemed to have more energy in the highest register.
One thing the RME and Callia both had in common: they both sounded better being fed optical from the Lyra. The ADI-2 Pro also has an optical output, but it did not produce an improvement in the Callia. I would not say that's enough data points to say one device's optical conversion is better than the other; more likely just a case of component matching.
