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WaveTheory

100+ Head-Fier
Holo Audio Spring 2 DAC Review - By WaveTheory
Pros: A clear step-up from the Bifrost 2/Ares II/dac1321 tier of DACs. Excellent detail retrieval, timbre, and spatial presentation. Smooth without sacrificing resolution. Lots of input options. Excellent build quality.
Cons: Macrodynamics are not clearly better than Bifrost 2/dac1321. Form factor is not desk friendly. USB connection drops upon input switching. Single-ended output and DSD performance are lackluster.
NOTE 1: This review was originally published on HiFiGuides Forum on 19 March, 2021. https://forum.hifiguides.com/t/holo-spring-2/16142/177

NOTE 2: The Spring 2 has been recently discontinued in favor of the Spring 3. I post this review now to hopefully help anyone hoping to score a deal on a used model...there will likely be some in the near future. (This review was posted on Head-Fi on 14 May 2021, for context).


INTRODUCTION

Several weeks ago, a fellow HFGF member reached out to me and asked if I wanted to listen to his Spring 2 Level 2 DAC while he was in the process of moving. What was I to do? Well, say ‘yes’, of course, and then listen to it and write a ridiculous amount of words about that listening experience. So, I did say yes. And I listened. And now I present that ridiculous amount of words about the experience.

I spun my wheels a bit trying to figure out how to describe the Spring 2 in a meaningful way. Until the past 2 weeks it had been the only DAC with an MSRP at $2000+ I’d ever heard. Reviewing, even just listening to, the first piece of gear in a new price/performance tier up and making sense of it is often a challenge because of lack of market context. Fortunately, a Chord Hugo 2 arrived within that last two weeks which provided at least one more datapoint for DACs in the price range. Even so, I recommend that you keep in mind my knowledge of and listening experience with DACs in this tier is limited. Sadly, I will not be able to answer definitively if the Spring 2 belongs among the ladder DAC saints. What I have a firmer handle on is what is gained by moving up from the upper $100s level of DACs to this level, and I’ll comment on that in this review.

TL;DR

The Spring 2 Level 2 DAC comes closer than any other DAC I’ve heard to date (which, I have limited experience with DACs in this tier) to being a piece of audio gear that just gets out of the way and lets the music speak for itself. It does little to announce itself in any particular way. It has a very compelling combination of detail retrieval, soundstage size, imaging accuracy and separation, timbre, and smoothness that makes it sound very natural and even transparent with classical music and other acoustic genres. And while it certainly is no slouch, it’s not overly dynamic or punchy, which might make it less than ideal if the primary use cases are for rock, metal, EDM, hip-hop, or music that is generally dynamic and energetic. However, for my first foray into DACs around $2K, the jump in performance from the $700-1000 level up to this price point was readily apparent with all genres of music I threw at it.

FEATURES & BUILD

The Spring 2 is a discrete, balanced, resistor-ladder (R2R) DAC. There are 3 levels of the Spring 2 DAC named Level 1, Level 2, and KTE. Reading the parent company’s (Kitsune HiFi) product page, it appears that the difference between levels is in the quality of electrical components (like capacitors and filters) used, in addition to Levels 2 and KTE including a remote control. The unit loaned to me is a Level 2. The Level 1 lists for $1698, Level 2 for $1998, and KTE for $2698. The owner told me he spent around $2300USD for a landing price for this Level 2. All levels decode PCM signals up to 32-bit and 1536KHz and DSD up to DSD1024. There are also both oversampling and non-oversampling modes.

Physically, this is a very large DAC. It has a large footprint and is heavy. It will not work well on a small desktop, although the chassis is robust enough that it would be a reasonably good monitor stand. But yeah, it eats up a lot of desk space:

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The chassis case is aluminum with copper-colored metal buttons on the front and very attractive, shiny, copper colored metal panels on each side. The front panel has a large, dimmable LED display that give sampling rate info, input info, and NOS/OS mode info. The back panel has the expected analog RCA stereo single-ended outputs, 3 pin XLR balanced analog outputs, and a plethora of digital inputs: USB (3.0, fits both USB-B 2.0 and 3.0 standards), I2S, Toslink optical SPDIF, 3 pin XLR AES, and 2 coaxial SPDIF - 1 RCA, 1 BNC). The USB connection will deactivate when a non-USB input is selected, ie the connection between DAC and computer will break. This is rather standard for USB devices of all types, but there are less expensive USB audio devices (anything with Schiit Unison USB, Soekris dac1321 as examples) that will maintain the connection between DAC and computer when optical or coaxial are selected. For many users who connect only via USB or have a streamer with USB output only this will not be an issue. However, I find that it’s easier to manage exclusive audio modes in operating systems when the USB does not disconnect with input switching and I think it’s fair to expect that of devices of this price going forward.

The remote control is simple but aesthetically matches the DAC:

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The volume control buttons do not work on the Level 2. I used the remote very little as I used the Spring 2 in a desktop setting and the buttons on the front panel of the unit itself have all the same functions save volume control. The remote is solid brick of aluminum with copper buttons. It has good weight and feel, except those copper buttons aren’t mounted firmly and jiggle around audibly when the remote is moved about.

SOUND

Test Equipment

Amps I paired the Spring 2 with were the Violectric HPA V200, Headamp GS-X Mini, and Cayin HA-1AMK2. Headphones used were Fostex TH900 with Lawton Purpleheart chambers and driver-side mod, JPS Labs Abyss Diana Phi, Audeze LCD-24 and LCD-2 Prefazor (revision 1), Massdrop + Sennheiser HD6XX, and 3 HiFiMan models: Arya, Edition X V2 (HexV2), and HE1000V2 (HekV2).

Modes Notes

In general, I noticed that I preferred the non-oversampling (NOS) mode. It was a little cleaner and more detailed. I’m finding this to be a trend; when there is a NOS mode on a DAC, I prefer the sound using it. Thus, my observations of sound are from using the NOS mode.

DSD and Single-Ended Performance

It should be noted that DSD performance is much like the OS mode performance. It’s solid, but not to the level of NOS mode for PCM content. Also, the single ended output is good, but clearly not up to the level of the balanced XLR output. If you buy this DAC, plan to use it with its balanced outputs. And if you own 500 SACDs, this may not be the DAC for you.

Sound Signature

The question of sound signature, at least from a frequency response standpoint, was a question I really struggled to figure out with the Spring 2. I couldn’t put my finger on any particular frequency range that I perceived as emphasized any more than any other. Terms like ‘warm’, ‘bright’, ‘mid-forward’, etc. just don’t really apply here. I’m a firm believer that every piece of audio equipment has its own character and that no one piece is truly neutral or transparent, but I have to conclude that the Spring 2 Level 2 is the piece of kit that has gotten closer to true neutral than any other piece I have heard to date. Now, I haven’t heard anything close to every piece under the Sun, but after weeks of trying to figure out a ‘signature’ here I have no better term than ‘neutral.’ I fully acknowledge that there may be other DACs in this price class or higher that get even truer to neutral, but I am confident in saying that it will impress me if it happens and that it would also take me some time to realize that it is happening – as it took me significant time to realize that’s what’s happening here.

Detail Retrieval

There is lots of detail here. In my LCD-24 review (link!) I mentioned how that headphone did a great job resolving the resinous sound (that ‘zizzy’ sound) of a bow being dragged across a string. The Spring 2 was the DAC that really brought that out. Similarly, things like crowd noise in live recordings or the creaks of chairs and sounds of pages turning in classical recordings are also resolved remarkably well. Even when music gets very busy or aggressive – be it lots of information like in a full symphony or the sheer attack of metal music – the Spring 2 keeps its cool and separates all the individual sounds from each other very well. This resolution is also done very smoothly and subtly. The detail is not aggressive or over-emphasized; it sounds quite natural. Cymbal hits have a distinctive two-part sound in the impact of stick-to-metal, and then the tone of the vibrating cymbal that follows. In my HiFiMan Arya review (LINK!) I mentioned that the Arya was the first headphone I heard where the term “texture” started to make sense to me in the audio context. It was the Spring 2 that initially brought that out. From there, I could detect texture from other, less expensive DACs, but only because the Spring 2 gave me that initial clarifying – call it a “spherical chickens in a vacuum” (https://www.youtube.com/watch?v=oUwlEdz42xo)– moment. Overall, prior to the Spring 2, I just didn’t know what I was missing. There’s a lot of subtle little things in music we often take for granted. Bringing it out makes listening to even very familiar music all the more enjoyable – at least for me.

Spatial Presentation

The soundstage of the Spring 2 is one its standout features, IMO. It’s big without being artificial. With symphonic recordings it created a believable sense of concert-hall sized space. At the same time, it’s also capable of creating an intimate space for smaller scale music like chamber music or easy-listening jazz. The imaging is also believable, placing instruments in positions that neither announce themselves nor feel like they don’t belong. The sense of depth is also impressive with nicely separated layers front-to-back. The overall spatial presentation is quite coherent and feels seamless without overemphasizing anything nor losing anything in the shuffle.

Timbre

The qualitative aspects of the sounds of individual voices and instruments is also a standout feature here. There’s a level of realism and accuracy to the sounds that is missing with lower-priced DACs. The resinous sound I spoke of earlier is both a matter of detail retrieval but also of timbre. A real violin string will make that zizzy sound when a bow is dragged across it. Said sound is easily heard live, yet many entry-level and mid-fi systems struggle to resolve it in a recording. The Spring 2 reminded me that it’s a thing. Its presence makes the sound overall more believable and convincing. Similarly, human voices are also closer to sounding like real human voices than other DACs I’ve heard. The nuances of swallows and lip smackings and even breathing that we hear when we talk to people in real life (remember that?) or listen to live, un-mic’d performances are also here. Does it sound real? No. Does it sound more real than other DACs I’ve spent time with? Yes.

Macrodynamics/Physicality

If there is one area where the Spring 2 didn’t clearly separate itself from the $700-1000 tier, it’s in the areas of punch/slam or general energy. The bass extension is good with plenty of rumble, but the impact or punch of an aggressively plucked bass guitar string or kick drum hit is not markedly better than a Schiit Bifrost 2 or Soekris dac1321. That is not to say that the slam or dynamics are poor, they are good, they are just not the standouts that spatial presentation, detail retrieval, or timbre are in comparison to this lower tier. For most acoustic music extension and timbre matter more than impact/slam insofar as creating a convincing reproduction of the real thing, and that’s where the Spring 2 excels. If your music taste leans more toward the active/aggressive/energetic side, the Spring 2 is still good, but will not be the significant improvement in macrodynamics that it is in those other areas. The Spring 2’s dynamic presentation drew me in more for classical works and jazz than it did for rock or metal.

COMPARISON WITH OTHER DACS

Alternate Heading: DACS REALLY DO SOUND DIFFERENT AND SOME EVEN SOUND BETTER THAN OTHERS


Moving From Mid-Fi to Hi-Fi

Prior to listening to the Spring 2 my top DAC experiences were Schiit Bifrost 2, Soekris dac1321, and Denafrips Ares II. The Ares II was sold recently to help fund some personal upgrades.

Compared to the Bifrost 2, the Spring 2 is more resolving, has similarly sized soundstage, but images and separates more believably within that soundstage. The Spring 2 overall sounds cleaner and more accurate, IMO. The Bifrost 2 keeps pace in the bass punch/slam and rumble departments, but is outclassed in virtually every other area. The Bifrost 2 also has a warmer signature where the Spring 2 is more neutral. Ergonomically the Bifrost has the ability to switch inputs without breaking the USB connection, as well.

The dac1321 has fairly similar sonic characteristics to the Spring 2, at least by ear it was more difficult to tell whether I was listening to the Soekris or the Holo in a quick-switch testing situation…at least at first. The dac1321 has excellent detail retrieval for its price, very good imaging and separation, and may have a signature that is slightly v-shaped in that it is both analytical and bright but also has a fair amount of warmth and bass heft. Even so, the two sound reasonably similar with the two most notable comparisons being the dac1321 sounding more intimate in its staging and also having at least equal, and maybe slightly better, bass punch/slam than the Holo. In time, from the Spring 2’s balanced outputs I was able to hear and appreciate the differences between the two more easily and start to realize that the Spring 2 really is comfortably higher performing in most areas of technical performance, it just doesn’t announce itself as being so. From the Spring 2’s single-ended output the gap tightens. Here the stage width of the Spring 2 is still noticeably wider than the 1321, but that’s the only easy difference to pick out. The Spring 2 is still more resolving from the SE output, but that was not at all easy to pick out, even after several hours of trying to hear differences. Ergonomically, the dac1321 also has the ability to switch inputs without breaking the USB connection with a computer. The dac1321 is also single-ended only, which may matter if ground loops are a concern for whatever system it might be considered.

To summarize the jump from the mid-fi level to the Spring 2, the Spring 2 improved detail retrieval, timbre, imaging and separation. I found that the macrodynamics, things like punch and/or slam or the overall energy level, were not significant improvements from dac1321 or Bifrost 2 to Spring 2. However, particularly in the low end, while the Spring 2 didn’t punch or hit harder, it was more resolving and brought out textures more than either of the other two, moreso over the Bifrost 2 than the Soekris. The sonic presentation of the Spring 2 is overall more believable than dac1321 or Bifrost 2, and that believability gap is not necessarily small. It’s all over my notes that the Spring 2 sounds more real, it gets me closer to buying that I’m in the room where it happened. Given that all these DACs are very even in punch/slam/macrodynamics, but the Spring 2 is noticeably superior in every other technical aspect of performance, I can comfortably say that it is the better sounding DAC. Yes, it sounds different than dac1321 and Bifrost 2, but because of its higher technical proficiency in almost all areas it is also clearly better than either of those other two. I cannot answer if the increase in price is appropriate for the increase in performance for you. I also cannot fault anyone for thinking that this performance improvement is worth the money to them. I think that latter statement is particularly true if that user likes classical music and other primarily acoustic genres.

The overall build quality of the Spring 2 is also an improvement, with the gap over the Soekris being bigger than over the Bifrost 2. Ergonomically, the Soekris and Bifrost 2 are more flexible, IMO, insofar as it’s easier to manage exclusive modes given their ability to switch inputs without breaking the USB connection to a computer. The Spring 2 does allow connection of up to 6 sources, though, where the Bifrost 2 and dac1321 both top out at 3. I’m sure there are users for whom this will matter.

A Mostly Lateral Comparison

I recently scored an unbelievably good deal on a Chord Hugo 2 transportable DAC/amp. The Hugo 2 currently lists in the $2495-2695USD range for a new model. It also has a headphone amplifier and battery built-in as it’s meant to be a travel solution, it appears, but is still quite competent as a desktop/2.0 channel system DAC. It’s an FPGA DAC design. Its presence here has given at least one more datapoint in this price tier of DACs.

The Hugo 2 has a more intimate soundstage, more akin to the dac1321 than the Spring 2. Both the Spring 2 and Hugo 2 image and separate sounds very well. It was hard to pick out any differences there. The Hugo 2 has a more analytical signature and a more energetic sound, emphasizing transients more than the Spring 2. I think the Spring 2 Level 2 may be slightly more resolving, but the Hugo 2 comes across as more detailed initially because of that emphasis on the transients. That same emphasis also gives the Hugo 2 noticeably punchier, at times almost tactile, macrodynamics, particularly in the bass. That also leads to more bass texture from the Hugo 2 than the Spring 2. The Spring 2 extends into the lower regions more than the Hugo 2, however, consistently having more rumble in the low end. Kick drums illustrate the differences in the low end quite well. With the Hugo 2 the initial punch of the kickdrum can almost be felt, but the weight of the bass tones that vibrating drum skin creates is pulled out more by the Spring 2. The Spring 2 also has a smoother, more relaxed presentation throughout the entire frequency spectrum. At times, the Hugo 2 could sound like it was announcing its detail retrieval, whereas the Spring 2 was just quietly going about retrieving details, doing the job without having to be noticed.

My preference between these two DACs comes down to musical genre. For classical/acoustic music, I prefer the Spring 2. It’s smoother nature, more expansive staging, more natural-sounding detail retrieval, and the slightest edge in vocal and instrument timbre, work together to create a more realistic and believable soundscape for those genres. For more energetic or aggressive genres, like rock, metal, EDM, or hip-hop, the almost tactile attack and overall transient response of the Hugo 2, while still having excellent imaging and timbre, are more engaging and connect me to the music more.

With both at roughly the same price level, I’m comfortable saying that the Spring 2 and the Hugo 2 sound different but neither is clearly across-the-board better than the other. The choice of Hugo 2 over Spring 2 will come down to sound preferences, preferred genres, and matches to use cases.

FINAL THOUGHTS

This was FUN! Playing with a true hi-fi DAC was an absolute joy. I learned about texture with the Spring 2. I was transported to concert halls with the Spring 2. It really is a nice piece of kit. I certainly understand why some get sticker shock. $2000 is in no way chump change for the average audiophile. At the same time, I can’t slag anyone who says that the sound it produces is worth the money to them. There can be magic here. The Spring 2’s spatial performance, timbre, and detail retrieval work together to create very coherent and convincing reproductions of acoustic music genres in particular. The Spring 2’s macrodynamics aren’t class-leading, but are far from poor in their own right. A heartfelt ‘thank you’ to the owner who lent this to me.

Enjoy the music, everyone!
koso
koso
Very nice review!
koso
koso
I have just purchased/ preordered Spring 3 KTE. In my opinion, after the first batch of Spring 3 units will be out for sale, there will be definitely some Spring 2 units for sale here and there. We just have to wait...
W
WaveTheory
Thanks for the kind words! I tend to agree we'll see some S2's on the used market soon. I don't know what the value will be. Depending on where the used price settles they could either be a stupid good deal or you'd just be better off buying the S3. I'll be watching...
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