NuForce HA-200...Dual Mono Madness! Page 2


The Basics
As much fun as it might be to dive right in to monoblock operation, the sensible thing is to figure out how these things perform on their own. Frankly I wasn't all that excited—doesn't the HAP-100 already have this area covered? Aside from being more affordable, isn't the HA-200 redundant when used by itself? Surprisingly, that ended up not being the case at all. My initial investigation had me feeding a single HA-200 with the $399 Asus Essence STU, which seems like a reasonable combo that folks might be likely to use. The HA-200 immediately struck me as being superior to the integrated amp in the Asus. That headphone out isn't terrible by any means, but when compared to the NuForce it sounded downright anemic and brittle. A dedicated amp—even a reasonably priced one such as this—will almost always pay dividends over a combo unit... until we get into the four digit price range where some DACs have exceptional headphone sections on board.

Anyway, back on track: I really liked what I heard from this setup. Using a Sennheiser HD650, which again seems like a reasonable pairing, I spent some time combing my library for past favorites. I ended up settling on what I consider a minor classic—Pedro the Lion's debut album "It's Hard to Find a Friend." With deliberately lo-fi aspirations and molasses pacing, this is decidedly NOT audiophile demo material, but it has a soul to it that transcends all that. One gets the impression singer David Bazan recorded this in his bedroom over the course of a 3-day weekend, mixing and mastering it himself on his lunch breaks the following work week. With material such as this, I believe a sort of Hippocratic approach is in order—First, Do No Harm. Instead of unraveling complex layers of detail, the system merely needs to maintain whatever meager fidelity might exist. This is actually tougher than it may initially seem. Think about it for a second: if Diana Krall takes a hit in clarity, the result still sounds far better (on a technical level) than any top 40 fodder. But if I can scarcely comprehend David Bazan's singing even under the best of circumstances, then all is lost when I introduce a component with recessed vocal range. Having established that, the Asus/NuForce/Sennheiser combo definitely passed the test. In fact I think it seemed very slightly sweeter in the midrange compared to the more "matter of fact" HAP-100, thereby making it that much more engaging. The difference, though small, was one I'd have to flesh out through further listening.

Switching gears, I moved forward in time to the appropriately named "Headphones" project, which had Bazan giving his take on indie synth rock. This time around we get far better production values—actual bass and reasonably extended highs for example—without veering from Bazan's thoughtful lyrical scattershot. The HD650 is not necessarily known for its pounding sub-bass presentation, and this album is no dubstep rumble-fest anyway. Yet the HA-200 is able to tease out a satisfying amount of punch, keeping the action flowing on tracks like "Natural Disaster" which combine synth elements with real live drums. Switching back and forth between the two NuForce amps I was hard pressed to tell any difference at all this time around. The HA-200 might be slightly more engaging in exchange for a wee bit of transparency, but the difference is subtle enough to be a non-issue. That similarity doesn't hold up across the board with every headphone though, as we'll discuss momentarily.

The last stop on my little David Bazan retrospective was his 2009 release "Curse Your Branches." The album, searing indie rock with vestigial traces of the Headphones synth experiment, has Bazan switching courses from "faith, with questions" to "disbelief, with ever gnawing hope". It's also by far a better recording than any of his prior work. It was mainly recorded in his basement, so drums remain rather "live"—we can hear reflections from ceilings and walls. The difference is that mixing and mastering were far more carefully done this time around, using respectable equipment even by audiophile standards. The setup includes names like Benchmark, Black Lion Audio, Lavry, Bryston, and some nice B&W monitors. As a big fan (read: nerd) I of course had to own every version in existence, and I played them back over my little Asus/NuForce/Sennheiser system to see if I could pick up the differences between each one. Which I could. The original mastering, used for advance promotional copies, is fairly warm but also a little sparse on top end extension. It's very dynamic but also quiet in terms of absolute volume, so it was necessary to really crank the NuForce on this one. The result is a satisfying overall experience that fits well with Bazan's style. Next comes the original retail master which opens things up significantly. Former band member Timothy William Walsh completely redid the EQing—originally done in software with plug-ins, this time around he took advantage of his recent upgrade to some API mastering EQs to handle things in the analog domain. The result is some added creaminess in the lower mids and significantly more top end detail. The downside is that he also tried to bring up the levels more than he probably should have. That means more compression and less dynamics. Transients are a bit dull this time around, and the whole album has a bit of "squishiness" to it (his word, but I agree). So I like this one about as much as the original but for different reasons. My favorite version was unfortunately only released on vinyl—this one is similar to the retail CD version minus the dynamic compression. It's got the dynamics of the promo release plus the clarity and extension of the CD remaster, making for a wonderfully open experience. I don't do vinyl but had a buddy convert it to 24/96 FLAC using his Clearaudio Ovation turntable and a Benchmark ADC1. The NuForce amp brought out the improved dynamics far better than the integrated Asus amp section and made the whole thing worth the trouble. Maybe this is why some people love vinyl so much—even without discussing the inherent quality of the medium itself, they do tend to get the good stuff when it comes to releases.

Forgive me for rambling on about music that I enjoy...well, that's the whole point, isn't it? The NuForce HA-200 is good enough to shine a spotlight on these works of art, which inspire us to invest so much time and money in this hobby. Without that, it's kind of pointless in my view. As cliche as it may sound, a good amp gets out the the way and lets that artist speak to us through our headphones, without causing distractions. There are plenty of expensive amps which do this quite well, and (unfortunately) some expensive ones that don't—but I'm always pleased to find it in a $349 model.

Okay, more specifics. The HA-200 is dead quiet and has a 5 ohm output impedance. That's slightly higher than ideal but still low enough to work well with most full size headphones. In-ear monitors are generally pretty good too, though some with wild impedance swings might not sound their best. In my collection, this means the Unique Melody Merlin (which drops to 12 ohms at some frequencies) is off the table. The Westone ES5 is very sensitive and dips down to 20 ohms at times, so on paper it's not the best match. In practice I still enjoyed it immensely which illustrates how you really need to try things out for yourself before making up your mind. The JH13 FreqPhase and my new favorite custom IEM, the Noble Audio Kaiser 10, both sounded exceptional as well—did I mention how much I appreciate the gain not being outrageously high?

One area I noticed where this new amp outperforms the HAP-100 is when using power hungry planar magnetic designs. The HAP-100 did a fine job at low to medium levels but ran out of steam when asked to play really loud with an Audeze or HiFiMAN planar. The HA-200 had no such trouble. I really enjoyed the richness of the LCD-2 and the speed of the HE-500, though the HE-6 sounded a little strained and thin. On the flip side, I still think the HAP-100 is a better match for the HD800. That combo has a special synergy that really stands out. HD800 aside, I'd call the HAP-100 slightly more accurate or clinical, while the HA-200 is more emotive, more engaging, and more "fun". But this is a subtle thing and by no means a large coloration.

Double Trouble
So..... it's a pretty good amp, right? Vaguely competitive with the more expensive HAP-100? Yep, it is, and if that's where it stopped it would be a pretty worthy accomplishment. But the dual mono aspect opens a whole new can of worms. Will the result be twice as good? Will it compete with amps in the $700 price bracket? Can it do justice to the HiFiMAN HE-6? The answer to those questions is no, yes, and absolutely, in that order.

Interestingly, the NuForce home series does not currently have a source component with balanced outputs. One might take that as a sign of things to come, but really I have no idea what NuForce has in store for us on that front. So instead I used a Yulong Audio D200 DAC which at $699 is a near perfect match for the HA-200 pair. I also note that NuForce doesn't appear to sell any XLR cables at all. I use (and enjoy) their Focused Field interconnects but they appear to be discontinued and never came in XLR anyway. So the user will need to source their own interconnects as well as their own balanced headphone cables. I used Cabledyne Silver Reference for the former and CablePro Freedom series for the latter, but the choices are practically endless.

The first thing I tried in monoblock mode was my trusty LCD-2. Moment of truth...was it better? Yes! Twice as good? No, but that's a rather unrealistic goal in my view. I did note a distinct improvement in dynamics and low end extension, and—rather important for the LCD-2—a more expansive soundstage. Switching to LCD-3 brought the same benefits, as did moving to Alpha Dogs and HE-500. Across the board, these models all had a more effortless feel when driven by the monoblocks. Probably the largest improvement came with the HE-6 which I noted earlier didn't quite sound amazing with a single amp. The monoblock pair pushed this thing farther than I've yet heard from a sub-$1,000 amp, resulting in a beautifully neutral, well extended, wide open sound. This is noteworthy because I'm accustomed to using the $1,899 Auralic Taurus mkII as a reference for these headphones. The NuForce combo doesn't quite have the same realism, but it comes closer than I would have thought. And it does so for less than half the price. Not too shabby I'd say. The only limitation I might be a bit concerned about is the maximum volume. For me, it was plenty, and I rarely passed 75% or so. But I know some people prefer listening at higher levels than I do. Those types, when using quiet jazz or classical material, might find themselves wanting a little more volume. I imagine the vast majority of people would be fine though.

Dynamic headphones saw less of an improvement than their planar magnetic counterparts, but it did remain beneficial to go monoblock. The HD650 seemed to open up a bit while the HD800 got even open-er, gaining some rather welcome low-end oomph in the process. While the HAP-100 outperformed a single HA-200 with that particular headphone, the monoblocks easily walked away from the competition due to their low-end dominance. I don't have a balanced termination on my beyerdynamic T1, which is too bad because I think it would be a significant benefit. The dual amps seem to exhibit more control over the drivers which is always a good thing with the sometimes harsh T1.

Unfortunately the rest of my collection is also hard wired with 1/4" jacks—Audio Technica, Grado, and AKG, why don't you all offer easily replaceable dual entry cables across the board? That's an important point, and actually something to think about when considering this amp—will you be able to take full advantage of it? An HD650 or LCD-2 cable can be easily had on the cheap these days, but recabling certain other headphones requires open-cup surgery. Are you prepared to go that far for an improvement?

I really have no way of knowing what exactly causes the benefits I hear in dual mono mode. Common sense tells me it's some combination of the increased voltage and current, plus the doubling of power supply. Remember—in monoblock mode, we get separate toroidal transformers, voltage regulation, and capacitor banks for each side. If you believe the audiophile lore about power supplies being the key to a good amp, then it all makes sense. If this whole thing offends your sensibilities, keep in mind that amp makers have actually been doing this for years—they just typically build a dual mono design into the same enclosure. The previously mentioned HeadRoom Blockhead was literally two amplifiers combined together. The DarkVoice 337 used mirrored internal components and also took separate AC cables to power each side. The more common configuration looks something like the Firestone Audio Bobby which has most components mirrored, but shares a single multi-tap transformer and only requires a single AC cable. The idea is the same though—doubling of components and separating each channel for higher performance.

NuForce has the right idea here—start with a really nice amp, price it very aggressively, and add in the monoblock option as a twist. I hazard to guess relatively few HAP-100 users take full advantage of the preamp functionality, so it makes sense to offer this simplified and more affordable option. I even think the new model sounds better in some areas than its higher prices sibling, making this an all around success. I can therefore happily recommend this amp to most anyone looking for a solid-state option with equally solid value.

I mentioned earlier that a pair of HA-200 amps is probably not twice as good as a single amp. Please don't take that the wrong way. It says more about the quality of the amp when used on its own, and the general nature of diminishing returns, than any deficiency with the monoblock scheme. With the right headphones, dual mono mode is absolutely worth messing with. A solid recommendation from me!

NuForce, Inc.
47865 Fremont Blvd
Fremont, CA 94538

lithium's picture

Thanks for the great review John...I really like the entire upgradable concept despite all the need for balanced cables and adapters. So why no hall of fame? It seems you liked it a lot

John Grandberg's picture
Thanks! As for the Wall of Fame versus Stuff We Like status.... I went back and forth on that one. What it came down to - my current nominee for WoF, the Lake People G109P, is currently in Tyll's lab for the ongoing measurement project. So although the dual mono HA-200 setup is roughly the same price and possibly outperforms the G109P, I don't feel comfortable bumping the Lake People without a direct comparison. I'll revisit them both when I can.
purplegoat's picture

Thanks for the review! These have been making quite a splash in the HE-6 corner. How do you feel about the HA-200 vs. the Yulong A28 on the HE-6 (another lower cost pairing you reviewed favorably)?

John Grandberg's picture
The Yulong is a perfect example of a true balanced amp in the more traditional single-chassis format. It's a great amp, especially with the HE-6. In fact I'd say the HA-200 combo and the A28 are fairly similar overall, in terms of general performance and sound signature. I do think the dual HA-200 goes slightly farther when it comes to getting the most from the HE-6. And I very much prefer using a single HA-200 as opposed to running the A28 in single-ended mode. However, the A28 does better with the LCD-2, where it has a bit more pop in the upper midrange (which is desirable with my particular LCD-2). I also like A28 with the HE-400 and Thunderpants too. Monoblock HA-200s strike back with LCD-3 and Alpha Dogs. So it's a pretty even match overall. Sorry if that's not completely helpful....
purplegoat's picture

That's very helpful actually, I appreciate the comparison. Do the the dual monoblocks beat the balanced A28 in clarity and speed for the HE-6? I'm assuming they do but I'm really curious as to how much. Should I feel the need to upgrade?

Thanks again

John Grandberg's picture
Yep, you got it - faster, more transparent, and ever so slightly more weighty. When starting from scratch I'd recommend the NuForce combo every time. That said, the A28 remains very satisfying. Is it worth selling your amp to switch? That's debatable. Not sure I'd go through the hassle for a relatively smallish increase.
purplegoat's picture

Noted. Thanks for the comparison!

achristilaw's picture

Nuforce could add a bit to the price and have models with stepped attenuators. Add some precision to the balance of dual mono. I'm not a fan of steps for easy to drives, the ortho crowd would run up those "steps" to snag a pair, two models and much more versatility.

John Grandberg's picture
Not a bad idea, maybe the resistor ladder network from the HAP-100 would do the trick. It's actually not too bad matching volumes as it is though. Maybe some markings around the volume knob are all it needs.