MST FiQuest headphone amplifier and Cio MB DAC in Review

Two years ago, boutique manufacturer MST rocked headfi by teaming up with iBasso to create what was arguably the highest quality portable amplifier on the market. Getting one required some patience as MST are a small outfit with a few employees. Their FiQuest, which has been upgraded in the year 2012, is better than ever. In this review, TouchMyApps will be looking at two versions, plus a small optical DAC.

Build quality
As you can expect from a Japanese outfit, things are put on straight. The FiQuest is less a portable amp than it is a transportable all-in-one portable/desktop replacement amp. The FiQuests large battery keeps it humming for 7-10 hours depending on load and usage. Because of its size, and because of its designer, ergonomics – as they apply to a transportable amp – are very good. Point number one: the in and output ports (all metal affairs) are spaced perfectly. No matter how large your headphone and input cables are, they will fit. And the ports are anchored well into the board and into their niches on the amp’s faceplate.

MST use slide switches for bass and gain rathe than knobs or flick switches. Considering that the FiQuest is primarily a transportable amplifier (and ostensibly not subject to the same amount of bumping as small amps are), the slide switches may be overkill. Small amp makers should take note: flip switches are easier to break, MST chose right. And, overkill that protects one’s investment is always good. In fact, it’s excellent.

The on/off switch is a flip switch, but it is a shallow-trunked affair that is as likely to break as I am to get that pay rise I’ve been begging after for years. Good for the FiQuest, rotten for me.

The one item that bothered me two years ago bothers me still. It’s the thin-pitch bolts that fasten the front and back plates to the chassis. If you’re in the habit of frequently and haphazardly opening up your FiQuest, eventually you will strip the bolts. I guarantee it. So be careful. The FiQuest is a joy open and dink around with. In fact, it is so customisable that it almost begs you to dig and dig. Just make sure you use good tools and don’t cock your hands at hard angles.

Ergonomics and Polish
As I hinted at above, ergonomics are damn good. In fact, despite being such a beast, the FiQuest is quite simply one of the easiest to use amps. It’s not just the switch panel layout or the spacing of the in and output ports. It’s the heft, which balances easily in the hand, never too bottom nor too top heavy. And even at low volumes, great balance is achieved from the large, smooth volume pot.

This is the FiQuest I remember. And it is wonderful.

Charging functions are on the back, and again, implemented via slide switches. The power supply is chunky, but so is the male jack and pin on the FiQuest’s bum. You won’t break it. Again, small amp makers with chintzy plugs, take note. This is the way to ensure you have fewer hardware malfunctions.

Apart from that, though, MST’s amp really is a straightforward metal brick. Fitting it into the pocket of any trouser is not recommended. It is simply too big. While I find the array of in/out ports very good, I’d like the output to be 6,3mm, not 3,5mm. Ryuzoh said the FiQuest is primarily a portable amplifier – a fact I well understand – but so is the GoVibe Portatube+. A 6,3mm jack just simplifies the use of other headphones.

Next, neither gain nor bass settings are labelled. You have to find your own way with the FiQuest, or just listen to me. Right is start, left is end. MST are Japanese. Keep that in mind.

Late night Music fans, the lamp on the FiQuest will not brighten your room like the sun like Vorzüge’s amps do. As great as they are, the Vorzüge amps are in dire in need of circumlision (in case my language is too deep for you, that’s the combination of circumcision and light, meaning nothing less than circumcision of light. How’s that for professional writing?) MST’s lamps are understated, more so even than ALO’s masterpieces, if that were possible. And believe it or not it’s pink. Damn. And I thought MST had grown up.

I’ll start this off reiterating how good the FiQuest volume pot is. It is the best I’ve used among portable amps of any price. Balance is perfect. And because the FiQuest has three levels of gain, low really is low. If you are using this monster with earphones (and trust me, there is good reason to), you will have no problem achieving left/right balance. If you are using it with headphones that need either lots of voltage or stamina (which some people call current) you are in luck.

Just as it did two years ago, the n FiQuest features a bass boost. It’s understated just like it was back then. It amplifies up to ~3,5 decibels. You will hear it, but you won’t be blown out of your seat. You want to know its polar opposite? Vorzüge.

Gain settings are gregarious: 0dB, 9dB, and about 20dB. Medium and low gain settings enough for any headphone out there, and because they impact signal quality very little, are most recommended. High gain is like the 230km/h top speed limit on your minivan’s speedometer: it makes you look like a badass in front of your kid’s popular friends, but is best left untested.

Which brings me to sound.

Two years ago I had one reservation: IMD errors forced at loud volumes from low ohm earphones. MST rectified the issue in a hardware release. If you have the first or second or third batch, you might opt to send your amp to MST for a tune up.

Today’s models need nothing so much as a willing ear, and a thick wallet. Now, there are several models to choose from, each offering slightly different sound. I’m sure MST would argue with me on this point, but this is MST’s baby. I’m a hardened reviewer with calloused ears. Small differences faze me like a mosquito phases a space shuttle.

That said, I can definitely see that the different flavours will appeal to different users.

The Accuro-bat
While there is no such word, there is a gaggle of amps that follow what I feel is the purest audiophile dictum: neutrality. Among powerful portable amps, MST’s FiQuest is a strong fighter. Its signal is clean, lean, and never damns itself by stepping where it shouldn’t. While its size sets it apart, sound-wise, the FiQuest almost completely disappears.

But it’s not just signal neutrality and authority that advertise MST’s latest opus; its the FiQuest’s coy noise signature, and resolution. This amp is powerful enough to whip the Audeze LCD-2 into shape, yet gentle enough to handle a FitEar To Go! 334. Noise simply doesn’t enter into the FiQuest’s picture in the way it does MST’s desktop-replacement competition. And resolution is extremely high, yet somewhat cozy.

Even engaging gain and bass boost does very little to harm the signal. There is no deleterious noise anywhere. That said, of course you will have less background noise in an amp like a Pico Slim, but then again, target headphones for each device are completely different. Among desktop replacement amps, the FiQuest is the trump card, and I am impressed.

The midrange is full of springy energy. Acoustic guitars resonate with pure, fast attack; decay is speedy and frontal, displaying its meaty underbelly to the ear. On low and medium gain settings this presence is as clean as clean can be until the volume is pushed too high. If you need extra oomph, choosing the next gain setting is your best bet to retain the same fidelity. Again, I recommend low and medium gains.

Sound in a nutshell
MST employ neither low nor high pass filters in their amps. Their bass and gain circuits play kindly both with the most sensitive of earphones and voltage-hungry cans.

The FiQuest’s father, Ryuzoh, assured me that my favourite headphone, Beyerdynamic’s DT880, would require the best spec and best parts to sound best. The poor lad needn’t have worried. The DT880 is driven so well by any flavour of FiQuest that I simply have to chuckle at the semi-worried face he had before I put my recommendation behind the combination.

The only proviso is that if you are stupid enough to play your DT880 600Ω at ultra-high volumes when fed from weak sources, you should keep move the gain up rather than maxing volume on low gain. Overall, overhead is high; at normal to medium-high volume settings, every earphone/headphone performs without flaw. But when passing 90% on the volume pot in low gain and whilst under load, the FiQuest spits out moderate levels of distortion. The audible effects are debatable since at those volumes, your eardrums are likely to collapse rather than delightedly hammer away to your favourite tunes. But for the sake of pushing an honest review, I’ve got to say it.

The FiQuest is as powerful at full volume as the Centrance DACmini PX. Surprisingly, ALO Audio’s The Pan Am is quite a bit more powerful with the likes of the DT880 600Ω. Of course, the Pan Am doesn’t play as well with earphones like the FitEar To Go! 334. And, when I say ‘power’, don’t misinterpret it for ‘pleasure’. At those volume levels, it’s your headphones or ears that will be destroyed.

There is no way this side of hereditary hearing loss that anyone would need anything more than a FiQuest to drive their DT880 of any ohm rating and sensitivity to deafening levels. More impressive to me is that the sensitive TG334 is driven equally authoritatively.

That brings me to this conclusion: despite its general coy indifference to whatever is plugged into its output, the FiQuest delivers truly excellent resolution all the way along the frequency path. I know that its tight, smooth treble will gain fanatics. Its bass is surely in for the same fate.

The bass gain settings go up in baby steps: less than 3 dB on gain 1, and just over 3dB on gain 2. This maturity is borne of dedication. MST’s house sound is resolving with energetic midrange and excellent reach in both treble and bass. Bass holds more texture than treble, which, for a solid state amp, is intimate and forgiving. Sibilant earphones and sensitive ears may find the FiQuest’s grainless treble presentation indispensable. Indeed, this box is a powerful, portable alternative to a high-class valve amp.

Scaling with better sources
There’s no need to ask. Yes, the FiQuest amp is capable of meeting your system. Feeding it from an iPod or Walkman will reveal most of what it is capable of, but stepping up to a Cypher Labs CLAS or CD player will only reveal more. Herein lies a question: with such power and resolution and the ability to scale from source to source, why doesn’t the FiQuest have RCA inputs? I’d love to plunk it down in my HiFi system connected via RCA cables. Assuming that the analogue input section is implemented well, channel separation and noise should improve even further with RCA input over the current 3,5mm input.

But, the FiQuest is a portable amp. RCA inputs seem right out of place, don’t they?

Best headphones for the FiQuest
I’ve sung some pretty high praise for this amp. And overall, it deserves it. While the FiQuest plays no real favourites with regards to what is plugged into its output, take a look at it. It’s huge. And powerful. And looks like a skinned wireframe extrusion. It really fits a desktop better than it does a pocket or bag.

Medium-high headphones are close to perfect. There are no checks in my spirit warning me to suggest to LCD-2 and K701 headphone users to suggest a different amp. The FiQuest is about as good as it gets – that is, as long as you are using a strong line-level output and keep the volume below 80% and stay away from the high gain setting.

Sensitive high Ω headphones like the DT880 600Ω and the FiQuest are somewhat of a mixed bag when run from equipment like naked Apple iDevices. To avoid distortion, use a Cypher Labs CLAS and apply the gain settings liberally. But, that is only if you tend to listen to insanely loud volumes. At normal listening levels, the DT880 is an excellent friend to MST’s amps.

Ryuzoh plugs custom earphones into his FiQuest and hangs the stack from a cool leather belt at his side. He’s hardcore. I’m not. But I’ve met many hardcore portable audiophiles like him out there. For them, there may not be a better portable amp to connect to custom earphones when on the go and to power full-size headphones at home. The FiQuest has more power, more control, and a uniquely fine-tuned bass gain circuit that enhances the lows for any headphone out there than any rival in its class. The fact that it is done maturely is a testament to MST’s devotion to quality rather than quantity. In short, for custom IEMs and high-end universals, the FiQuest is perfect. If you are after the largest soundstage and super-detailed treble, there are slightly better options on the market. If you love the resolution of solid state amps, but sometimes find treble to sometimes be painful, take a look at the FiQuest.

The Cio MB DAC
How cute is this little box? Just like the one I tested a few years ago, this is a high-performance optical DAC that works well with a MacBook Pro, Go-DAP X, Go-DAP Unit 4.0, and Fostex HP-P1.

It’s tiny. It’s battery lasts for up to 10 hours. There are small optical cables on the market. Everything seems in order for it to take its place at the top of great portable systems -that is, except output volume.

Its line out is underpowered. Plugging it into a HiFi or external headphone amp will reveal less pressure than an iPod or iPhone. Indeed, it steps down more than 10 decibels from the output of an iPod line out.

But, its signature is lovely. There is very little interference that gets into and out of the box. The sound is laid back, smooth, hearkening back to CD players of old. Connected to the FiQuest, it makes you want to curl up with favourite jazz CDs and knock back a bottle of wine.

Is performance isn’t aimed at better-than-16-bit like the CLAS; rather, it exerts soft control over the entire gamut of metrics, toning here and prodding there until even the harshest recording sings in engaging, mellifluous accents. I recommend it for lovers of NOS parts, valves, and vinyl. It is a digital piece that injects a little analogue magic into a system.

On the flip side, if you gauge DACs by absolute resolution, no matter how brittle, the Cio MB isn’t for you. Stay with the CLAS.

Gain – unlike its mature bass settings, gain settings are aggressive. An approximate 9dB gain in medium position is quite a jump. The high gain performs like a proof-of-concept rather than a real feature. Sure, you’ll get loads of extra volume at high gain, but you’ll obviate some of what makes the FiQuest so special. Resolution remains high, but dynamic range is compressed slightly. Interestingly, the DT880 600Ω and FiQuest on high gain at any comfortable listening level remind me very much of the Pan Am. I love the Pan Am, but the two are very different beasts with very different audiences.

Volume DAC – the Cio MB is a wonderful product in a small, sturdy package. A battery-powered DAC is most welcome. But its output is quite low. Even an iPod outputs more SPL into a headphone amp. Paired with the FiQuest, you’ll have to bump gain quite high with headphones like the DT880 600Ω, and move the volume pot into somewhat dangerous territory.

Volume FiQuest – despite offering enough (in fact, more than enough) volume to any headphone out there, the FiQuest does so with less precision than it should. Maxing out any volume setting reveals more distortion than necessary. And of course, there is the maximum gain setting, which I feel is unnecessary. Features for the sake of features are sometimes better left out.

3,5mm only – this is a portable amp. Ryuzoh reiterated this many times in our conversations. It is a wonderful portable, but it can replace bulky mains amps, too, and works wonders for a large majority of full-size headphones. I know I am not the only one who wishes it came with a full-size 6,3mm stereo phono plug. This isn’t an issue; it’s an observation. But, it’s a pointed observation about an amp that deserves the full monty.

The FiQuest would be the perfect amp if it weren’t for its somewhat mild volume issues.

I actually published this review about a month ago, but for some reason left it private. Such tardiness is unpardonable. But in the meantime, I’ve had the chance to discover the Pan Am, another intriguing desktop replacement amp.

In terms of resolution, the two carry on in two very different ways; the Pan Am goes the way of warmth and intimacy, while generally, the FiQuest attacks from the perspective of resolution. Interestingly enough, the Pan Am’s absolute volume ceiling with hungry headphones such as the DT880 600Ω is quite a bit higher. At such volumes, it suffers comparatively less distortion, too.

But, the FiQuest is easier to finely tune, and runs the full gamut of headphones from the likes of custom earphones to the mighty DT880, better overall. But, because of my private publishing boner, I can add the following addendum:

The FiQuest is the 2nd most powerful portable amp I’ve used for full-size headphones.

MST run an uncompromising business. For just about every headphone out there, their amps are overkill – and that is a good thing. It’s better to start out from a position of strength. The FiQuest boasts excellent resolution and volume balance. And wonderful bass circuitry. Its lows and mids attack with energy and resolve with fine detail. Treble is ever so slightly forgiving. Indeed, this is an amp for custom earphones and high-end universals. It is an amp for high-end full-size headphones, too. MST have come a long way and despite a few polish niggles, deliver one of the best amps at any price.

Excellent resolution
Excellent volume balance
Lots of power
Good ergonomics
Taught, energetic sound

Unlabelled sound controls
Test-mode style 3rd gain setting

Hot damn! Headphones really are a rockin’ way to enjoy music, right? Feel free to explore TMA’s headphone oubliette

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