LSA DPH-1 Headphone Amplifier

I love discovering reasonably priced products, squarely aimed at bringing great sound to more people, and new people to our wacky world of audio.

Underwood HiFi scores big time with their new LSA DPH-1 headphone amplifier, which also has an onboard high-res (does DSD too) DAC featuring four inputs. LSA makes use of the AKM 4495 DAC chips and AK-4118 digital input receiver, for those wanting to know…  I say, “implementation,” and in this case, they’ve done a fantastic job.

Right now, in typical Underwood fashion, they are running an introductory special and moving these babies for the holiday season at $799, instead of the $999 they will be asking at some point. Even at $999, this would be a great deal – let’s investigate a little further.

If the DPH-1 were only a headphone amp at $999 it would still be great. The DAC is a true bonus, and it makes the DPH-1 fantastic for personal listening, desk side or bed side. It’s small (14” x 10” x 4”) footprint makes it easy to integrate anywhere.

Ins and outs

Around the back, there are four digital inputs – USB, optical, coax and BNC. Personally, I like the BNC as I have a vintage Wadia transport, which I pulled out of mothballs to give the DPH-1 a spin. Interestingly, you’ll notice a pair of RCA analog outputs marked “Tube” and “Solid-State.” This is really cool and gives you more options, should you decide to use your DPH-1 as a line preamplifier. And if you happen to be a digital only music lover, the DPH-1 is all you need.

The tube output runs the DAC’s output through a tube buffer, featuring a “NOS tube from GE.” Turns out this tube is an ex-military issue item that is very similar to the legendary Western Electric 396A tube. Those of you that aren’t tube geeks: plugging your power amplifier into the tube output will give you a slightly warmer, more tonally saturated presentation. This is super awesome option for those of you running a solid-state or class D amp, and it works miracles on budget amps too!  Consequently, the solid-state outputs add a little extra dynamic slam to your favorite tube amp.

You can even run both the tube and solid-state outputs into your integrated amp or preamp and switch sonic characteristics on the fly. It’s like having two separate DAC’s in one box. Or, as we do with our reference DAC here, if space allows, or you have systems in adjoining rooms, you can run both systems from the same DAC. Very versatile indeed.

That being said, mating the DPH-1 to a vintage (but tastefully rebuilt) Dynaco Stereo 70 and the LSA-10 Signature speakers was absolutely heavenly. Either way, the ability to fine tune your system to taste is cool, especially at this price.

Getting personal

Running through the gaggle of headphones on hand, from the $3,000 Focal Stellia to my Grado SR-60s, the DPH-1 delivers an excellent experience. The amplifier does a great job driving everything, and has particularly good control in the lower registers. Zooming through some vintage Little Feat tracks, particularly “Romance Dance,” from The Last Record Album, reveals the DPH-1s ability to control a pair of headphone drivers and deliver a convincing musical foundation. Next up, the Bell Biv Devoe classic, “Poison.” If I was listening on a 2-channel system, I’d be blowing the doors down with bass – and as it was, I caught myself turning the volume down, because the distortion free playback this amp provides might tempt you to turn it up too loud. So, watch the volume.

After a solid sampling of phones, the bulk of our test listening was done with the Focals, showing off just how good this amp is. Regardless of where you are on your headphone journey, you’ll be able to move up from wherever you are to some pretty premium phones without worry. That’s value.

Bass is not the only dimension at which the DPH-1 excels. Joni Mitchell just released her Archives – Vol. 1: The Early Years (1963-1967), and this set handily shows the inner detail, definition and upper range smoothness this amplifier offers. Joni Mitchell’s voice is a tough one to nail down – almost like a violin, when it’s wrong, it’s harsh and shriek-y, but when it’s right, it’s dreamy. We’ll happily put the DPH-1 in the dreamy category here, and this lead us to some of the tracks on Lyle Mays self-titled debut album. Nailing the tonality of a piano is similar in degree of difficulty, and again the DPH-1 sails through.

There’s a sign on one of my neighbor’s lawns that says “Presidents come and go, but Wu-Tang is forever.” Point taken, so on the way back from my morning coffee, I had to fire up some Wu-Tang. In their honor, I cranked up “Method Man” as the six-shot mocha took hold. Good stuff.

The DAC section of the DPH-1 does its job without fanfare, as it should be. We tried all four inputs, and were pleased each time, using our Wadia transport for the BNC input, an OPPO 105 (yep, still got one) for the coax input, a MacBook Pro for the USB input and our faithful Sony ES changer from the garage system to evaluate the optical input. Suffice to say, whatever you have, the DPH-1 will accommodate it, and the higher resolution capabilities this DAC provides easily illuminates the additional resolution that high res formats have to offer. Good as it is with high res, the DPH-1 does not compromise 16/44 playback in any way.

Putting the DPH-1 in the context of a nice two-channel system makes for a great, compact music system, requiring minimal rack space to rock. Whether you buy a DPH-1 as a headphone amplifier, or as an anchor to a digital two channel system with a pair of speakers – you’ll be happy wherever your journey begins.

Simple elegance

LSA has followed the aesthetic vibe started with their other components, and the DPH-1 is nicely finished, but not overly ostentatious. It feels good when you unbox and pick it up, and it looks great on your rack. Its basic functionality (volume control, input selector, and headphone jack) makes it easy to use. Fortunately, the power supply is built in, so there’s no external power supply to lose or deal with. A big plus.

By using casework like other LSA products, they keep the cost down. When you’re investigating components in this price range, it’s nice to see a manufacturer stick to basics, striking a balance with a product that sounds great, and has the looks to back it up without going overboard.

Add it all up and LSAs DPH-1 is a fantastic DAC/Headphone amp. If I didn’t spin records, I could easily live with it as my main two-channel preamp and build a great system around it featuring speakers. It ticks all the boxes – easy to use, reasonable price, and sounds fantastic. What else do you need?

The Questyle CMA600i Headphone Amp/DAC

One of the most exciting things to come out of the headphone revolution is the plethora of desktop headphone amplifiers that either include a high-performance DAC, or a phonostage yet can also be used as a line level preamplifier. These are the coolest boxes in hifi right now, because they are a great bridge to both worlds.

Bruce Ball’s Questyle brand has been lighting up the internet, and the hifi shows now for some time with good reason; their creations sound fantastic, look stunning, are built to an incredibly high standard and won’t break the bank. The CMA600i featured here is a full resolution DAC that can handle anything up to 24/192 PCM files and offer True DSD conversion to DSD 256 as well. That spells future proof in our book.

Great as the high-res capabilities are, the CMA600i’s ability to provide breathtaking sound with standard 16/44.1 files is what makes this small but mighty headphone amplifier an incredible value. Listening to Al DiMeola’s Flesh on Flesh, streamed via TIDAL, all of the nuances of this guitar great come straight through. Though known for his ability to shred like no other on an electric guitar, his light touch on the acoustic guitar on this album is lovely rendered by the CMA600i, played back through my Conrad Johnson MV60SE tube amplifier and a pair of new Quad 2812’s in my living room. This review began using the CMA600i as a linestage/DAC combo first, and it kills everything I throw at it.

Super sleek style

Built in the Foxconn factory (the same people that manufacture iPhones), the CMA600i feels like a much more expensive component than its $1,295 price would suggest. Picking it up for the first time is deceptive, as it looks like it should weigh a lot less. Thanks to top quality parts inside from Wima, Dale, Alps and a big power supply transformer from Plitron, the CMA600i is beefy.

It doesn’t contribute to the sound, but the space gray finish, combined with the carefully machined corners on the casework make for an incredibly fashion forward visual design too. It looks more like something you’d expect from Nagra and that’s one of the highest compliments I can pay it. With the power supply in the casework, there is no annoying wall wart to lose or degrade the sound. Again, way more than you’d expect for $1,295.

The layout and operation are straightforward, and from a human engineering standpoint, the CMA600i is highly intuitive and easy to use, even without consulting the manual. Ball has concentrated on bringing you everything you need with nothing you don’t. Around back are USB, coax, and optical digital inputs and they all sound great, plus they give you the option of switching between three digital sources. Great stuff, but adding a solitary analog input so you can plug a turntable in, is sheer genius. Running a pair of interconnects from the $15,000 Audio Research REF 3 Phono again shows just how resolving the CMA600i is. Switching between the Soulines Kubrick DCX (reviewed in issue 80) and the Rega Planar 3, the CMA600i has more than enough capability to illustrate both of these turntables.

If you’re staying in the preamplifier groove, the CMA600i features both RCA and fully balanced XLR outputs, allowing any amplifier to be used. Driving a 20-foot pair of balanced Cardas Clear interconnects to my Pass Xs 300 monoblocks was a breeze. Comparing the 20 foot run to a 3-foot pair showed zero degradation in sound quality, a testament to how robustly this preamplifier is built.

Ok, ok, how about plugging in some cans?

It was so much fun using the CMA600i as a preamplifier, it took a while to get around to headphone listening, but again, there was no disappointment. The current mode amplification does it’s thing and moving from planar phones from Oppo, Audeze and my torture test favorites, the HiFi Man HE-6s, everything I could throw at the CMA600i proves to be effortless.

Listening to the acoustic version of Grand Funk Railroad’s “Stop Lookin Back” the high resolving capability of this headphone amplifier. The attack and decay on the acoustic guitar have plenty of texture, feel and transient attack. Staying in boomer rock mode, the marimbas in Frank Zappa’s “Central Scrutinizer” bounce around my head in a highly psychedelic manner, with Zappa growling in the background, somewhere deep in my cranial cavity. As the late, great Mr. Zappa used to say, “Isn’t this what it’s all about?” The answer is an unquestionable yes.

The sheer current drive (Thanks to the Class A Current Mode Amplifier) of the CMA600i keeps even the most difficult to drive phones in line. There is no wimping out dynamically or at the frequency extremes as can happen with headphone amplifiers that don’t have the power supply to back them up.

Tonally, the CMA600i is very neutral and again is not affected by phones connected. Where something like the Benchmark DAC 1 family tends to be slightly dry, and some of our favorite tube headphone amplifiers can embellish with a bit of extra tonal saturation, the CMA600i plays it straight. Those wanting the more lush sound of a tube amp might be turned off, but again, after extended listening with about 20 different pairs of phones, the neutrality of the CMA600i is a plus. I suspect headphonistas with a broad collection of cans will love it as much as I do.

Those liking strong bass response will not be disappointed, tracking through some EDM and hip hop favorites is convincing. Going way back, Koop’s Sons of Koop through the LCD-2s is stunning.  Even my Koss Pro 4aa’s that I’ve had since college sound phenomenal through the CMA600i – I’ve never heard them handle the lower frequencies with this kind of authority, and I’ve been listening to these babies for a long time. The ability to connect via either of the two ¼-inch, front panel jacks or the 4-pin balanced input, means everyone can join the party.

Digital versatility

A handy switch on the front panel lets you toggle through digital inputs with ease, making it easy to use whatever sources at your disposal. Giving things a go with a Mac Book Pro and the Aurender W10 server both provide excellent results. Listening to nothing but high res tracks via the Aurender quickly validate the additional resolution, switching back and forth between TIDAL and high res versions of the same tracks. The only aspect of the CMA600i I wasn’t able to fully explore was its ability to decode DSD files, as I have a very limited selection of tracks on my server. Suffice to say what I heard was excellent; however, I did spend quite a lot of time with 24/96 and 24/192 files.

Unlike a great number of DAC’s that use the Sabre chip family, Questyle walks to a different beat, taking advantage of the AKM4490 and its “velvet sound” architecture. While we can wax poetic all day long about the nerdy details, it is well implemented in the CMA600i. The Questyle website mentions that it is powered with a +/- 7-volt high voltage power regulator, to ensure high dynamic range. Listening to a wide variety of classical pieces makes it easy to see how well this works in practice. It is also worth mentioning that the CMA600i is fatigue free – long listening sessions are a breeze and digital artifacts, the enemy of hours in the listening chair, just do not exist here.

Whether listening through the phones, or speakers, I was never less than thrilled with just how much music the CMA600i reveals, especially in the company of some much more expensive hardware. Each component of the CMA600i is worth the $1,295 asking price on its own, if not more. Considering it takes up so little rack space, and you’ll save 2-3 times what the CMA600i costs on not needing power and interconnect cables for a DAC, preamp and headphone amplifier makes it one of the best values in high-end audio today. That’s why it has received one of my Publishers Choice Awards in issue 80. The CMA600i is certainly a teacher’s pet, and I’ve purchased the review sample to keep as part of the fleet.

A top performer

In the end, you can find a DAC or preamplifier that reveals more music than the CMA600i, but you’re going to have to spend a lot more money, whether you are making it the cornerstone of a high-performance headphone only system, or using it as the anchor for an incredibly good two channel system. This option makes it just as future proof as the ability to play all the high res formats in my book.

The Questyle CMA600i succeeds brilliantly on every level. It sounds great, is incredibly versatile and is visually elegant to boot. This is as good as it gets, and should you build a system around it; I suspect you will pass this one down to a family member. Well done Mr. Ball!

The Questyle CMA600i Headphone Amplifier/DAC/Preamplifier

MSRP:  $1,299

Pass HPA-1 Headphone Amplifier

Listening to Thomas Dolby’s “Ability to Swing,” the Acoustats in my living room have dramatically increased their ability to swing in every way: these vintage ESLs known for their somewhat loose and flabby bass now stand up and deliver Dolby’s snappy synth bass lines with authority.

The low level resolution that this preamplifier brings forth unearths minute details normally only heard on the TONEAudio reference system costing almost a hundred times more; all three dimensions of the sound field painted now expanded to the point of being psychedelic. In 35 years of listening to the Acoustats, they’ve never sounded this exciting. The slow sax fade in on Traffic’s “The Low Spark of High Heeled Boys” becomes conscious so deliciously, so delicately, as the accompanying instruments fold into the mix, it’s creepy the way these vintage ESLs wrap you up in sound.

But this isn’t Pass’ $38,000 Xs preamplifier; it’s their new HPA-1 headphone amplifier. This thing sounds so damn good twenty minutes out of the box, the thought of plugging a pair of headphones in is frightening, fearing my head will either melt or serious flashbacks will be triggered. So for the next few days, it merely does duty as the anchor of a modest 2-channel system, logging some hours on the listening clock. Before you start griping about the unobtainable price, the HPA-1 retails for $3,500 – hardly unobtainable at all.

Sheer genius

Wile E. Coyote lists himself as “super genius” on his business card, but I can’t think of guys more deserving of this title than Nelson Pass and his crew at Pass Labs. I’ve been buying his designs since his days at Threshold circa 1980, and I’ve never heard one I didn’t love. Not like. Love. Personal bias, maybe, but I keep trying everything else, finding plenty of lovely things, but when I come back to a Pass product, it just feels––or should I say sounds––perfect. So in case you haven’t been reading my reviews for years now, I confess my personal bias here, openly.

The HPA-1 is the brainstorm of the newest addition to the Pass team, Jam Somasundram. Speaking with him on the phone is highly enjoyable and he makes it a point to tell me that he “designed the HPA-1 as a linestage first,” giving it the necessary oomph to drive a power amplifier, so that driving headphones would be no problem. A man of major understatement, this thing is fantastic.

Even if you aren’t a headphone enthusiast, but have been shopping for a linestage in the $15,000 range, consider the HPA-1. (Remember, it’s only $3,500…) If you have a minimalist, yet high performance system and can live with two single-ended inputs and a lone single-ended output to your power amplifier, get your hands on an HPA-1 and spend the rest of the money on your system.

Pairing the HPA-1 with everything in the studio and at home from bare-bones vintage amplifiers up to the Pass Xs300 monoblocks used as the anchor to our main system is a treat. Comparing it to a number of other preamplifiers in the $5,000–$10,000 range, the Pass holds its own or outperforms them in terms of quietness, dynamic range and tonality. Once powered up for a few days, and played for about 100 hours, it opens up further, exhibiting a level of refinement you would expect from a $10k preamplifier. Remember, only two inputs, no remote and one set of outputs. But purely from a sonic standpoint, it is stellar.

From a visual standpoint, it looks like an Xs Pre put in a shrink machine. Its diminutive size is less than half of a standard component, making it great for a compact, yet high performance system, or the perfect desktop headphone amplifier.

Oh yeah, it’s a great headphone amplifier

Pass keeps the minimalist thing going here too. With only a single ¼-inch jack on the front panel, they haven’t addressed the balanced thing, or multiple outputs, merely concentrating on the one way of connecting that most headphones offer. Forget about that; this thing sounds awesome.

The Pass press release mentions that it will easily drive planar phones, and this is instantly confirmed with a quick test drive of HiFiMan, Audeze, and Oppo phones. Even the notoriously tough-to-drive AKG phones pose no threat to the HPA-1.

For those who haven’t had the Pass experience, Nelson Pass has said on more than one occasion, he “likes the sound of tubes, without the hassle,” that is, replacing tubes and the occasional catastrophic failure that can accompany high voltage and high heat. The HPA-1 sounds just like the current crop of Xs gear: refined, dynamic and quiet, with a tonal balance a few molecules to the warm side of neutral. Never a bad thing with today’s current crop of headphones, especially the top of the line Sennheiser phones.

After running through a wide gamut of phones to confirm no rocks in the road, most serious listening was done with the Audeze LCD-2s (current version) and the OPPO PM-1s. While this is a very well-balanced amplifier, its strongest suit is the sheer dynamic range it offers. Much like the Xs300 monoblocks we use daily, this extra dynamic range and grip helps whatever headphones you might have, fully controlling their diaphragm, resulting in quite possibly the most wonderful experience you will have with your current phones. Even my late ’70s vintage Koss Pro4aa’s took on new life with the HPA-1 driving them.

If you’ve ever been in a hifi show room, or trade show where the speaker manufacturer uses a massive power amplifier to drive a small pair of speakers with great result, you know what I’m talking about. It also gives whatever phones you are listening to extra oomph in the bass department. Favorite EDM tracks now really feel weighty, especially with the Audeze phones.

As you might expect, the stereo image produced by this amplifier on a premium pair of headphones is big, bold and exciting. A couple of times I caught myself getting up out of the chair, ready to walk away, thinking that I didn’t even have headphones on.

A $3,500 headphone amp with free preamp or vice versa?

Rather than bore you with audiophile cliché after cliché, let’s break it down. The Pass HPA-1 is on the top tier of the world’s finest headphone amplifiers, regardless of cost, end of story. If you can live with the single-ended functionality and a single output, you’ll have a tough time getting better sound anywhere. It is an expensive headphone amplifier, but delivers the goods. If you are only looking for a headphone amplifier, this is the top of the heap.

As the control center of a minimalist hifi system, it offers performance far beyond what you’d expect to get from a $3,500 linestage, and it has a world-class headphone amplifier thrown in for free. Again, if the topology fits your needs, even the most crazed audiophile could live the rest of their days with the HPA-1. It’s that good. Even if you never plug a pair of phones into the front panel and merely use it as a preamplifier, this is one of the best values in high-end audio today. And swing it does.

The Pass HPA-1