ot that long ago products coming from China were regarded as chip and mostly offering a mediocre quality (at best). And that „label” was used not only in regard of audio products but all of them. Since „HighFidelity” is an audio magazine lets focus on what has happened on this market during past few years. And what happened changed, or at least started to change our perception of Chinese products. Today most audiophiles can name at least few Chinese brands that offer truly high quality and high performance devices. Examples? I'll name only those I've dealt with personally: Lumin (yup, that's HongKong, but that's China now), HiFiMAN (with headquarters in USA, but it is a Chinese company), AudioGD and surely some other I simply can't remember at the moment. Nobody associates these brands with „cheap, poor quality” product. I'd even say that they earned respect of audiophiles around globe because of the quality of both: workmanship and performance.

Few months ago a fellow reviewer, Dawid, told me about another such brand called Questyle. What we had in common with Dawid was how we both loved the current mode Bakoon HPA-21 headphone amplifier. This beautifully made and wonderfully sounding amplifier had but one downside (from our perspective obviously) – its price. In Poland it costs bit more than 13.000 PLN which, for headphone amplifier is a lot (although I realize that is not the most expensive headphone amp on the marker). So in fact both of us hoped we could find some other product with similar performance but much more friendly pricing.
Whole credit goes to Dawid who found out about Questyle Audio, contacted them and negotiated sending the first review sample to Poland. And the review Dawid wrote was raving about CMA800R and after that he was kind enough to offer me a listening session so I knew that he might had founded what we'd been looking for. It so happened that representatives of Questyle Audio attended this year's Munich High End Show, which gave me a chance to meet Mr Alden Zhao, Questyle's Oversea Sales Manager. During the Show they presented not only CMA800R (two actually), but also D/A Converter CAS192D and Q192 – a single device combining DAC with headphone amp.

What caught my eye immediately was a presentation of two CMA800Rs working in mono mode and driving... yes, of course my absolute favorites Audeze LCD-3. Don't get me wrong – it doesn't mean that I disregarded other product, but I'd been looking for optimal and yet not too expensive (like other favorites: Bakoon HPA-21, and Sugden Masterclass HA-4) amplification for my cans for quite a long time. I just had to try this system immediately (with Questyle DAC as a source) despite far-from-perfect show conditions. These conditions didn't let me fully assess the performance but what I heard was enough to talk to Alden about a review of a pair of CMA800R. As it turned out he also was an Audeze fan, which made my getting two units for review easier. All I had to do was to wait for review units to come.

Maybe five minutes after I left Questyle's stand I (very happy indeed) I realize one „slight” problem. To conduct such z 'review I needed a special cable for my LCD-3, terminated with two 3-pin XLR plugs. Such a cable doesn't belong to standard Audeze equipment (I mean there is a balanced cable but with a single 4-pin plug) and you don't really see many of these also among after market cables. My first idea was to ask Forza AudioWorks to make one for me, but that would not be a standard model for them so after the test they would be left with an almost unsaleable product.
Solution came from unexpected side. Maybe a month before HighEnd Show I contacted Alex Sventinsky from WyWires. That's an American cable manufacturer that made a lot of fuss (mostly) on American market over last few years. There are lot of raving reviews, but also many comments from satisfied customers. All of them praising outstanding performance of cables that cost less, or much less that more famous competitors. We exchanged couple of emails and Alex wrote that he'd be attending Munich Show so we could meet there. For me WyWires owner's presence in Munich was a clear indicator that company was strongly interested expanding overseas.

We met and knowing that a lot of people praised also a headphone cable Alex offered I asked him if he'd be interesting of preparing a cable I could use for Questyle review. He agreed to make and deliver 3 m long cable with 4-pin XLR termination and another 1m extension cable with two 3-pin XLRs for my Audeze LCD-3 cans. Obviously in this way I would have a cable I could use not only for this review but also for any other headphone amp with a 4-pin balanced output. This RED Headphone cable costs in US 299 USD (for 1,5 m but one can order any length adding another 35$ per additional feet) and can be ordered for Audeze, HiFiMAN and Sennheiser cans (although versions for HD700 and 800 cost more – 349$ - because of more costly plugs). One can order it with jack or XLR, an extension cable is also an option. After delivery I could finally find out for myself that this was on one hand quite an inconspicuous cable (as it was rather thin) on the other eye-catching due to its beautiful red color. What was more important make and finish were of a high quality and the cable itself was very flexible and light – something that headphone users would surely appreciate. Alex used also high quality Neutrik plugs so Red Headphone Cable seemed like a solid contender which was to be confirmed in the course of this test.

It's time to get back to Questyle. CMA800R is not a particularly large device – which is a welcome feature for headphone amp. It sport a nice aluminum enclosure that is nicely made and finished. On a front panel there are three headphone outputs: two large jacks (6,3 mm) and one 3-pin XLR. The latter works in mono mode. There are also three toggle switches – (starting from the left-hand side) on/off switch, input selector (as there are two inputs, balanced and unbalanced), and a work mode selector. Even the volume control knob is made of aluminum and works smoothly. Five blue LEDs (not too bright which is great!) indicate functions currently used/active. These working modes are what makes CMA800R different from hundreds if not thousands of competitors. Each Questyle can work as a regular, stereo amplifier, but all it takes is just one flip switch and you can use it as a monoamplifier. Well, OK – you need a second unit obviously, and a balanced source plugged into separate inputs, and a special cable for your cans (with two 3-pin XLR plugs) – but hey, what other amp gives you this rare opportunity?
On the back you'll find above mentioned „regular” analogue inputs (RCA and XLR), IEC socket, pre-out (RCA) and a single XLR input that is used in mono mode. I started this text mentioning that together with my colleague we'd been looking for an amp that would perform at similar level. We'd figured that it also should be working in current domain (like Bakoon and unlike 99% of amps on the market). Questyle works in current domain although Chinese engineer claims that it is a lot different from Bakoon's design. Let's get to listening!

CMA800R +Hd8000

Bakoon HPA-21 is (not only in my opinion) a perfect partner for Sennheiser HD800. Well, I'd rather say that it makes them sound much better than any other amp but it still doesn't make my first choice of cans. After his session Dawid, an owner of HD800, told me that Questyle allowed these cans to perform as well, as they did with Bakoon. So even though I don't have these headphones myself Dawid insisted on letting me have his for the time of this review (he did the same when I'd reviewed HPA-21). I had to try them with CMA800R (with a single unit I mean – no proper cable to try them with monoblocks). Well, maybe to amplifiers are not enough for ultimate conclusion but I would still risk one. It seems that these cans truly benefit from being driven by current mode amplifier. I don't mean to start any war here – I know that there many happy users of HD800, but I'm simply not one of them. These are highly analytic cans offering tones of details, fast, with a rather bit bright and sometimes even slightly harsh treble. They allow to analyze sound material giving user a very good insight. I appreciate all that, I really do but that's not what could convince me to use them every day. Using them I don't feel such a close, intimate contact with music as is usually provided by Audeze, HiFiMAN, FAD and many other cans. HD800 bring, in my opinion, at least in a long run sort of fatigue and I don't mean physical comfort as these are the most comfortable cans to wear I know. But soundwise they kind of force themselves on a listener with abundance of very distinctive details that seem to be important by themselves instead of being a part of a greater whole. They also seem a bit „nervous”. And surely they don't offer such a slam as Audeze or HiFiMan, nor such a richness, fullness of sound as those, and while spacing is really good, all these elements offered by HD800 don't combine, again – in my ears – into... fluid, coherent music spectacle as I would like to hear it.

Unless, of course, you drive them with Bakoon's current output, or, as I just found out, to current Questyle's output because then it becomes quite a different story. With other amps both range extremes seemed to dominate midrange a little but with CMA800R it wasn't a case anymore. There was finally a rich, smooth midrange, there was some slam in the bass, and even treble seemed smoother, more liquid while still open and sparkling. Yes, I'd tried HD800 with other amps before like with above mentioned Sugden, or M2Tech Marley, and these, while being impressive class A products, had not worked with these cans that well, I mean – I hadn't liked none of these setups that much. It changed when I started to drive Sennheisers with CMA800R – I finally enjoyed listening to the music, and not just high quality sound, if you know what I mean. For my personal use I would still chose Audeze, HiFiMAN, and even FAD cans, but with Questyle in play the choice would be so obvious anymore. So if you are a fan of HD800 give Questyle a try – you might find out that your cans can still do better than with any amp you're using now. I know that it won't be easy as there is still no distributor in Poland (from what I heard maybe soon there will be one) but if you really try you'll find a way. Of course you can try with Bakoon – also a great, but much more expensive partner for these cans. Your cans will still be fast, detailed, transparent, but improvements in bass extension and slam, richness of midrange and smoothness of treble should be also to your liking.

CMA800R + FAD Pandora Hope VI

I was really looking forward to listening to Pandora's with Questyle but I had to do my sessions with HD800 first as I knew I had to return them to the owner. Again I had to perform a test with a single CMA800R because I lacked proper cable to drive Japanese cans with two amps. As I mentioned in my Pandora Hope VI review I liked these cans more and more with almost every session and when review was finished it was really hard to part with them. That's why now I have my own pair and my respect for these headphones hasn't ceased to grow. They simply don't fall that much behind top Audeze models as price difference would suggest. Combining them with Questyle proved to be an excellent idea and showed that there was still some potential in some ares to be discovered. What this setup introduced to otherwise already well know sound of Pandoras was more lively, more open sound, I mean these are features I didn't complain before but only improvement allowed me to realized that there was even more potential in them now delivered thanks to Questyle amp. CMA800R also gave bass bit more weight and slam while taking care of proper control and definition – with that pace&rhythm became almost perfect.

Obviously there were some things that even Questyle couldn't „create”. Bass extension still wasn't as great as with for example Audeze, but a better control, definition, more taut and more energetic presentation simply shifted my attention to these aspects and made me forget about any shortcomings. This dense, smooth midrange became even more subtle, sophisticated if you will, also more transparent which resulted in a better insight into deeper layers of music. Treble, slightly dark before, now started to shine and sparkle while still being detailed and open as before. CMA800R seemed to be a very clean, transparent sounding amplifier and these cans benefited from it greatly. What was great about this amplifier was that unlike many similar devices it was not sounding bright nor lean and the session with HD800 proved that it was capable of doing quite the opposite – make their presentation fuller, richer, smoother. So after session with so differently sounding cans I could tell that this was quite an all-rounder, that would sound great with (most likely) almost any headphones.

Surely it matters what source will you use with it. I loved the sound when CMA800R was partnered with Lumin T1 – a smaller, less expensive but equally great sounding brother of famous A1 model, It offered an involving, warm but detailed, open and resolving sound. I enjoyed Questyle a lot when my TeddyDAC was a source, or Accoustic Arts system (Tube DAC II i Drive II), or turntables (including my TransFi and Zontek). Have you already spotted a pattern here? Yes, in my opinion such a fast, transparent, clean sounding amplifier benefits most from some very musical, dense, rich sources, as they together offer a complete, outstanding presentation – analytic but musical at the same time, fast, detailed, resolving but also very smooth, rich, involving.

Obviously the choice is yours if you decide to purchase CMA800R and it will depend on the final effect you'd want to achieve. But from my point of view, considering my preferences combination of this amp with one of the above mentioned sources was all I needed. Now I still had to do was to check these combinations with my favorite cans from Audeze.

CMA800R + Audeze LCD-XC i LCD-3

Considering how thrilled I had been after my review of LCD-XC I simply had to try these also with Questyle. To be honest – I was able to do that because distributor still hadn't picked those up after the review – nice of him! These were the first cans I could plug into two CMA800R, as they used same cable as LCD-3. That gave me also a chance to compare the sound of LCD-XC driven by one and by two Questyles, although comparison wasn't perfect as I had to use different cables (single Forza Audioworks, and double WyWires). When I talked to Alden in Munich he told me that they had tried many cans with 2 CMA800R and the ones that benefited most from such amplification were Audeze LCD-3. But since I'd loved LCD-XC so much why wouldn't I have listened to them too?!
Listening to closed-back Audeze with Chinese amplifier only confirmed everything I already new about these cans, about how outstanding piece of audio equipment they were. On one hand it proved that CMA800R did equally great job as brilliant Sugden Masterclass HA-4 had before, on the other hand it showed that XC did not benefit much, or even almost at all, from being driven by two monoblocks. Let me be more precise – already one Chinese amp changed the character of sound of American headphones to some degree. While Sugden had put an emphasis on features like: richness, smoothness, tunefulness and so on, Questyle shifted accents towards: speed, transparency even better details reproduction. Let me underline that for you one more time – CMA800R shifted and not changed sound completely, nor even significantly. These were two outstanding amplifiers presenting a slightly different way to achieving outstanding sound quality. Listening to any of them I couldn't really point out anything I thought had to be improved. Only when I compared them directly I realized that maybe Sugden could be just a bit faster and more transparent and it wouldn't have moved it to the group of “cold sounding, analytic devices”. On the other hand Questyle could offer slightly richer, even more smooth and palpable midrange and that wouldn't have made an “overly warm device” of it. These were simply two amazing headphone amplifiers offering outstanding, although slightly different performance. And I loved them both equally, as they both allowed me to enjoy the music in a fabulous way. So when I finally hooked up LCD-XC using WyWires cable to two CMA800R, to be honest, I was slightly disappointed. Not because they didn't sound great, as they still did (!), but because they didn't sound even greater than before. I mean – after some time I noticed a slightly better dynamics, and it seemed that also control and definition of low end gained a bit. These were quite small, although absolutely positive changes but simple the extension of them wasn't as great as I'd expected.

So finally I arrived at creme de la creme of this review - Questyle with LCD-3. In my recent reviewed of LCD-XC I admitted that I liked them even more than my own LCD-3, although with one reservation – my LCD-3 pair was almost 2 years old, meaning no FAZOR on board nor any other improvements Audeze had introduced over this time. So one of the questions I wanted this test to answer was this: would CMA800R restore proper hierarchy among Audeze cans – LCD-3 was a top model after all. Already the first session with single Questyle amp proved that this unit was a very good match for somewhat dark sounding LCD-3. This incredibly dense, creamy midrange obviously benefited in terms of speed and transparency, and the low end became even more taut, more punctual and even more energetic. But it were changes in treble that made a real difference. It was treble that caused many people to call LCD-3 (at least this older version) dark sounding cans. There was plenty of details, it was resolving and open but it wasn't as vibrant, as sparkling as many competitors and it took a top notch very transparent and resolving amp to appreciate Audeze in full. One of such headphone amplifiers that did this sort of job very well was Schiit Audio Mjolnir. It was capable of “lighting up” the treble (not make it brighter but lighten it up, meaning giving better insight, making it more vibrant and adding some sparkling but without making it harsh or bright) and thus changing significantly this “dark” signature of Audeze. CMA800R did the same thing but I thought (couldn't be really sure as it'd been more than a year since Mjolnir's review) that it did even better job. It seemed that LCD-3 sounded even more “lively” and more transparent. As far as I could tell differences weren't huge but noticeable.

So the last thing to do was to hook up my LCD-3 using beautiful Red Headphone Wire from WiWyres to two CMA800R units working in mono mode, to finally check by myself whether that was the best way to drive my favorite cans and if buying two of them would really be worth it. Let me make it simple for you – the answer is: YES! Ever since I got LCD-3 I'd been repeating again and again that these were the best cans I knew, offering most complete. Most natural, sore sophisticated sound than any other I had a chance to listen to (at least the best ones that were still in production). But still plugging them into two CMA800Rs proved there was still some previously uncovered potential in them. The sonic signature of LCD-3 remained the same, and the improvements were more or less the same as with a single Questyle unit but what changed was the extent of the changes – these were no longer just “noticeable” but simply significant, bringing these amazing cans to a new level of performance. I'd never heard these headphones delivering such incredibly dynamic performance, with such a deep but amazingly well defined and controlled bass, and a slam that one would have thought cans could never convey. This system was able to convey even organs in a very convincing (I mean for headphones), powerful way. I was amazed how deep LCD-3 were able to go. Just for fun of it I listened also to many drum solos just to contemplate and admire dynamics, slam, speed and the outstanding way this system differentiated both low and high tones.

As for treble an exceptional differentiation was one thing, but finally listening (via LCD-3) to sticks hitting cymbals I could hear “sparkles” flying, as the strike was so strong, so well defined, but also a response of metallic cymbal was which in turned offered rich, powerful sound with a very nice decay. Other improvement, although not to such extend, was in term of spacing and imaging that seemed more precise which lead to even more realistic performance. I couldn't check how would HD800, FAD Pandora Hope VI perform driven by two Questyle amps, so it is sort of speculation here, but basing on the information from Alden and on my experience with LCD-XC I would risk a claim that it is the LCD-3 that benefit most from a system based on two current mode CMA800Rs working in mono modes. For LCD-XC, that are easier to drive, I would suggest a single CMA800R – that should be enough to create a fantastic system. But when it comes to LCD-3 two Questyles really make a difference. Obviously two units mean price x 2, but if one wants a top notch system that's a price one has to pay for it.
Is it worth to buy two amps (not only double price but add a special cable to it) that's a question each potential buyer has to answer himself. I have no doubts it is worth it if you want to have reference system with Audeze LCD-3 cans. Since I couldn't directly compare WyWires Red Headphone cable to any other I can't say for sure that it is the best possible choice, but what I can tell you is that this is a damn good cable that together with two CMA800R allowed LCD-3 to shine like they never had before. That means that it does all I expect from any cable – it allows the system to perform at its best. That's the best recommendation cable can get from me.

Summary

Having already great experience with current mode devices from Bakoon I expected a lot of current mode Questyle CMA800R. This test has provided me with a confirmation that current mode amplification is a way to go and I wonder why so few companies use this solution. A single CMA800R is a damn good headphone amplifier, one of few best I had a chance to listen to so far. It offers an amazingly clear, transparent sound, detailed, resolving and fast. But at the same time it is far from sounding “dry” or lean – with proper cans it creates rich, musical, convincing and involving presentation. It's also a nice all-rounder as such a different sounding cans as Sennheiser HD800, FAD Pandora Hope VI, and Audeze cans – they all benefited from what Questyle offered. There are a lot of very good headamps on the market but only few of them would sound that good with such a different headphones. Two of these amplifiers working in mono mode with a very smooth, rich and (if only possible) balanced source (like a Lumin player for example) and Audeze LCD-3 with WyWires cable create a reference system that only few could compete with. These brilliant cans seem to come really alive in such setup with enhanced dynamics and even more vivid, transparent presentation. The most evident “gain” comes in treble area that is lit up by Questyle, that isn't dark any more, that make treble sparkling, shining, and give even better insight. All that makes LCD-3 sing as I've never heard them before. Outstanding dynamics, deep, powerful but also very well controlled and defined bass, rich, creamy midrange more transparent, clearer than ever, but still palpable, offering very close, intimate contact with music.
And finally the one thing some complained in regard to LCD-3 about – treble that is surely slightly darker than offered by most cans on the market (that are, in my opinion, simply too bright). With CMA800R nobody should complain any more about “dark” treble – it is open, sparkling, but also rich and smooth, no signs of any harshness, any grain or whatsoever. Sound is amazing fluid, coherent and there is this combination of features that is offered by high end devices – amazing clarity, and a sound that is detailed and resolving but at the same time very rich and smooth, what we can hear is impressive in terms of dynamics, of the amount of energy that is conveyed but it is also subtle and coherent. If you ask me – that's what high end sound is about!

Questyle CMA800R is a current mode headphone amplifier. Lets start with its looks. Questyle sport a nice, not too big aluminum casing with a regular rectangular shape. Fit and finish is very good although there are some detail that in my opinion could still be improved (more about that in a moment). Thick front plate sports 3 toggle switches – (starting from left-hand side) on/off switch, input selector, and mode selector. Between first two there are four blue LED indicators (with user-friendly brightness). Than there are two (current) large jack headphone outputs, one 3-pin XLR balanced mono output, and a smoothly working, aluminum volume control knob.
On the backside, next to the IEC socket, there there two stereo analogue inputs: RCA and XLR (and thus an input selector on the front), a single, balanced mono XLR input, and unbalanced (RCA) pre out. The whole casing is supported by 3 or 4 (user can chose one setting over the other) solid, aluminum feet with additional rubber o-ring.
The mode selector, XLR headphone output and mono XLR input are used when two CMA800R units are used as mono amplifiers. One unit serves as right channel the other as the left one. I am not sure if there is any other headphone amplifier on the market that could work as both, stereo or mono amp. Woo Audio offers monoblock headphone amplifiers but these work as monoblocks only so one needs to buy a pair.

Let me get back to those little things concerning the looks and functionality that Questyle could do better (or improve in a future version). First of them actually concerns the case when two CMA800R are used – as both sport independent volume controls it would be helpful if there was some sort of a scale that would allows user to use exactly the same setting for both units (channels). As foe aesthetics – as the fit and finish of the whole casing is really good, the way top cover is fixed could be surely done better as these 8 not so nicely looking screws surely don't help.

I've started with information that this amplifier works in current mode – eve its name suggests that: CMA is an abbreviation for Current Mode Amplification. What does current mode actually mean? One should understand it pretty literally – signal delivered to amplifier, a voltage signal, as all source deliver this type of signal, is converted to a current one and then processed/amplified in a current stage and not like in most devices available on the market in a voltage one. The Current Mode Amplification consists of an Input Buffer, Current Transmitter, Trans-impedance Amplifier and Output Buffer, each section makes up a TransLiner (TL) loop circuit. CMA technology is traditionally applied in high speed communication and video processing fields but Questyle used it for audio and has patents for its proprietary solutions. Not unlike in voltage mode amplifiers this one also used transistors in a gain stage but these work in a bit different way. In Current Mode amplifier there are capacitors between each two transistors which affects speed and bandwidth working in a low impedance resistance. As the Manufacturer claims RC value is ultra-low, so it can easily achieve amplification with much broader bandwidth and ultra-low distortion plus it lowers TIMD (Transient Intermodulation Distortion). The parameters CMA800R provides are impressive – 0,00038% ultra-low distortion, 650KHz wide frequency and 114dB Signal to Noise Ratio.

Even for the best solution to work properly one needs to use high quality components and that's exactly what Questyle does. They use large toroidal transformer with few secondary windings that is made for this particular device by a Canadian company Plitron. Power supply section includes 22 pieces of high quality Nichicon Fine Gold capacitors, 1000 μF each. There is a 115/230V voltage selector which means they make same units for different markets. Volume pot is Alps 337G 50KAX2. Relay switching is via three Takamisawa, the two large Wima caps are MKP4 series 2.2uF 250V units. Gain stage includes high quality OPA627. Voltage signal is delivered via analogue inputs and than converted to current signal by VCCS (Voltage Control Current Source). Then current signal goes to gain stage and only after that is converted back to voltage signal, as only in this form it can be delivered via output to any headphones.

Specifications (according to manufacturer)

Gain: 15,5 dB
Maximum output power:
• 180 mW (7,5 Vrms) @ 300 Ω, stereo mode
• 710 mW (15 Vrms) @ 300 Ω, mono mode
SNR: 114 dB, stereo mode, 118 dB mono mode
THD+N:
• 0,00038% @ 1 kHz, 300 Ω stereo mode
• 0,00026% @ kHz, 300 Ω mono mode
Frequency response: DC-200 kHz (+0, -0,3 dB); DC-650 kHz(+0, -3 dB)
Input sensitivity: 1,2 Vrms
Impedance: 47 kΩ
Inputs: XLR stereo, RCA Stereo, XLR mono fully balanced
Outputs: 2 x large jack 6,35 mm, fully balanced single 3-pin XLR, pre-out (RCA)
Work status: pure class A
Power consumption: 13 W
Dimensions: 330x300x55 mm