Qinpu - A-6000 MKII - Integrated /Headphone Amplifier

Plato's "Allegory of the Cave" is a point of reference in this review because, after experimenting with this Qinpu a-6000 MKIi amplifier, I have reluctantly realized that my sonic reality has been nothing but phantasmagoria. It should not have been difficult to accept. After all, I returned to the analog world after listening to a Tracy Chapman record on a system whose heart was a pair of vintage McIntosh 275 amplifiers driving a set of custom-made speakers. Although bewildered by the quality of the sound, it was easy for me to rationalize--due to my limited budget--that any Solid State system would be able to achieve an approximate result. And with such a delusional premise, during the last 2 years I have embarked on a quest to find a suitable match between vintage amplifiers and speakers. The journey has involved receivers such as a Pioneer SX-780, a Kenwood KR-9600, a Technics SA-400, a Yamaha CR-800, two Concepts 6.5, a Concept 11.0, a Marantz 2015 and an Onkyo TX-4500 MKII; along with several sets of speakers, such as Infinity Qe, Boston Acoustics CR6 and CR7, Infinity Sterling 2005, Technics SB-L200 or A/D/S L1290. After an impulse sale of my Concept 11.0 paired with the A/D/S speakers (the investment was triplicated), my favorite matches have been the Onkyo with the Technics speakers and the Marantz with the Infinity Qe. In fact, although the horn tweeter of the Technics is amazing, I just love the sound of those Emit tweeters. Well, as a result of the Qinpu, that is history. Putting that conception of reality in the past, however, has been a somewhat painful process, for it just seemed unacceptable that, as Plato suggests in his analysis, I had been perceiving the shadows for so long--including digital media. Indeed, for a few days I refused to accept that this hybrid amplifier would be capable to ameliorate the sound of this format to the point that I kept A/B-ing a vinyl and a CD recording of Coltrane's Blue Train until I walked to the turntable to flip the record, but the music continued playing from the CD player. If fidelity entails the reproduction of a recorded live performance as faithfully as possible and high relates to the excitement of listening to it through an affordable piece of equipment, then this amplifier is definitely Hi-Fi. As suggested by the aforementioned equipment, I am far from an audiophile. So much so that I engage in the blasphemous practice of utilizing average speaker wires and interconnects. Moreover, although I have auditioned several tube amplifiers, this is the first time I have owned one to test with leisure. This review, therefore, elucidates my limited experience, filtered by my ignorance about superior equipment such as the one described in other reviews--some of which, incidentally, has been displaced by their owners after experimenting with the Qinpu. (I am rather grateful to all reviewers for allowing me to delve into the world of tube amplification with their sincere observations).IMPRESSIONS Having read and seen so many images of this amplifier before its purchase, weight, dimensions and looks seemed like an after-thought upon unboxing. I was very pleased with all of them, but the principle of instant gratification drove me to install it immediately, relying on the phono stage included in the Onkyo TX-4500 mkII, which was paired with the Technics SB-L200. My uneducated ears noticed a difference in soundstage and instrument separation immediately, but the midrange seemed distorted. The set up was shifted to the Marantz 2015 and there was a considerable improvement. I then switched the connections to rely solely on the Marantz and, initially, it sounded so much better than the Quinpu that I almost decided to return it. Taming the remnants of my impulsivity, I retrieved a TCC TC-450 phono preamp from a closet, connected it directly to the Qinpu and my jaw almost dropped. Coltrane's "Resolution" had never sounded so real, so alive. I continued to A/B between the two amplifiers until I was convinced that the Marantz indeed sounds tubey, but that I liked the Qinpu better. As so many reviewers have explained, soundstage, coloration, instrument separation, warmth, liquidity, vocals, etc., seem incomparable to that of a solid state unit. The sound, rather than being pushed from the speakers, flows out with cadence. In terms of power, going above 10:00 seemed beyond the point. I did it anyway for testing purposes, and it more than filled the room without noticeable distortion. Yet, I still continued to refuse the acceptance of this new sonic reality. So, I ordered some tubes in order to roll accordingly: GE 5670 five stars, Raytheon JAN 5670, and Bendix 2C51. While the valves arrived, I tested the Qinpu's capabilities with all types of digital media, even more vinyl, and several tuners. I became increasingly dissatisfied with the sound as the stock Chinese tubes burned in. As clarity, soundstage and instrument separation increased, the bass continued to fade away. I loved the three-dimensional aspect of the sound, as others have described. Yet, even the Technics SB-L200, with their 10-inch diameter woofer and 90db efficiency, did not seem to provide a pleasant bass experience, even though I am not a bass fan. I have to admit that some acapella versions that I played sounded extremely impressive, especially Lara Fabian's "Je suis malade." The tubes arrived and, as I had gathered from reviews, their respective qualities revealed significant improvements. Undoubtedly, the Bendix are superior, bringing the bass back to the point of sounding almost SS, but their superior definition of vocals and soundstage makes the experience of listening to anything, including Metallica or Peter Brötzmann, feel very real and satisfying (I happen to like both). I seem to enjoy the Raytheon set more, but believe that the GE five stars are a great value, especially for those who like their music loud, as their gain seems to be higher. The Raytheons provide all the advantage of tubes, but with a neutrality that fails to fatigue the ears. Or is that what the tube reality is all about? In my experience with any tube combination, the Qinpu works better with digital media, especially CDs, than with vinyl--although instrument separation is enhanced in the latter format. I listen mostly to Jazz in vinyl and it is rather satisfying to discover musical details that had been overshadowed before. Older records, such as pre-Liberty Blue Note, Prestige yellow "fireworks," Six-Eye Columbia, or early Impulse!, reveal nuances that I had simply not noticed before. Also, they sound fuller than DMMs or recent releases. Even with an Ortofon 30 stylus, I could not understand the superiority ascribed to a Six-Eye Columbia pressing of Miles Davis' "Kind of Blue." Now I do, for the tubes definitely bring it out. I will explore the Qinpu with a better phono pre-amp, as this may be causing the limitations I am perceiving with vinyl. Although I was also very pleased by pairing it with the Infinity Qes, I will try more efficient speakers in the future. I used a four channel speaker selector (with impedance matching) in order to connect 2 sets of speakers simultaneously. This quadraphonic or surround-sound set-up seems to have enhanced the 3-dimensional aspect inherent in the tube experience and I rather like it. Given the price and performance of this unit, I am not surprised that so many reviewers have been pleased with it, to the point of finding it superior than some of their high-end equipment. In my case, I simply like its sound reproduction better than any other equipment I have and find it very difficult to readjust to solid state reproduction while driving or in my office. It is important to note that the headphone problem reported by others was replicated in my unit: no stereo sound unless plugging the headphones a quarter of the way into the input. This problem should be resolved in further upgrades. The operating temperature seems about the same as the one from other receivers I own. On the fifth day, however, I placed a small computer fan under the toroidal transformer as a probably unnecessary safety procedure to prolong its life. Sound quality does not seem to be affected. As a minimalist, I love the design of the unit, especially the brushed aluminum finish (if it had been black, in spite of the positive reviews, I would not have ordered it). The wood accent provides a touch that balances the modernist design with contemporary aesthetics. I am not fond of blue LED illumination, but that will not be a problem because, as with all of my equipment--except the speakers, of course--the Quinpu sits behind closed doors in a specially designed audio-closet (the set-up is still aesthetically pleasing and the only black items in that place are cables or vinyl). I like the sound and looks of the Qinpu so much, however, that I may simply bring it out. Looking at it may reinforce the acceptance that there is a more satisfying sonic reality beyond solid state.

It's pretty good for a desktop stereo system, but it's not a true audiophile amp as many claim. The tubes are fairly noisy, but they do serve to warm up the sound. The bass is significantly rolled-off. It's not super-resolving, but it is musical sounding. The volume pot is not terribly accurate - on mine, at low volumes, the left channel is significantly louder than the right channel. They even out when you get to about 9-o'clock. Decent for the price, but you might be able to find some better sounding used gear at the same price. It's also annoying that the headphone jack is non-muting. You need to unplug your speakers if you want to use your headphones without bothering others. If you'll be doing that, I suggest putting banana plugs on your speaker wire. Otherwise, you'll be screwing and unscrewing the the cheap plastic terminal nuts constantly, and they'll likely wear out quickly. Speaking of cheap plastic, that's what the tube cages are. The tubes are also susceptible to picking up noise from 2.4 GHz signals, so if you have a computer on WiFi near this amp, either switch to a 5 GHz network, or make a MuMetal shield for the tubes. The warmth is nice, but ultimately I'd prefer to replace it with something that has a bit more punch to the sound. My main system is a much more expensive Naim setup, so perhaps the comparison is unfair to this based on the price difference, but I'm just used to much bigger, faster dynamics from my stereo.

Jokes apart this is a serious product. The designer shows his/her extreme craft with this unassuming and inexpensive creation. I have had amps (pure solid state) costing $1000-1500 and none produced the sweet sound of this device. Only other semi tubish device I had was the Peachtree Decco2 with a tube preamp stage and hell it didn't sing nothing like this little guy. It is so simple,it is criminal!My setup -Oppo 105 connected with XLR to RCA cables in stereo down mixed mode.Qinpu A-6000 - stock tubesSwan Diva 5.2 (90dB efficiency and 6 ohm impedance)20x14X9 untreated media room with carpet and painted drywall.(IMHO room acoustics is 40% of the total sound equation)Positives:Good things come in small packages too!Very refined, non-fatiguing, room filling and unrestrained sound with excellent imaging and wide sound stage. Bass is decent. You can pinpoint the location of instruments in the music. This guy presents vocals like nothing else - warm, lush and creamy. YMMV with the source material of course. The whole presentation is very organic and palpable. Well mastered source material transports you to a different world and puts the musicians in your room. That should be the final cliche for this review!This is my first real hybrid device hence I don't have any other hybrid device to compare with but compared to my SS devices this guy is way up there. I heard very expensive and well regarded Audio Research, Conrad Johnson, Cary and Manley etc tube int/amps at audio festivals and loved the sound very much but thought I had to spend the big bucks on tube amps get at least 50% of their sound quality but this guy for less than 1/10 of the price got me to 80% of the sound of the big guys. With upgraded tubes, it may get even better. Insane value!If you want the truth and nothing but the absolute truth, get the remarkable Benchmark DAC and Adam A7 studio monitors but if you want music that soothes the soul get this little guy and some efficient full range speakers. This guys lies but his lies tell the truth!Feel free to fill in rest of the audiophile superlatives here _____________________.Negatives:I feel the design is a bit cheesy and could be refined.Some rough edges and panel gaps.RCA and other connectors not good except for the speaker connectors and knobs.Non replaceable and flimsy power cord.Some humming when used as a pre-amp feeding a power amp.Headphone amp not very good with Senn HD650. No match for the Benchmark DAC.May not drive power hungry, less efficient speakers.Complements laid back speakers/dacs more than forward and bright speakers/dacs.PCB layout is not very clean.Can't turn off the blue lights under the tubes.No auto on/off.Long term issues not known.I'm not an expert on pricing, manufacturing process and rest of the logistics but overall I feel that it could have been designed to look a bit better while keeping the cost more or less the same.Take away one star.As one of the previous reviewers mentioned, if the same were manufactured by a high end company in a fancy machined aluminium unibody case with better design, features and connectors, you could be paying substantially more for just about the same sound quality. I would rather have a good sounding bad looking device than a bad sounding good looking device. When you feel good music you close your eyes anyway!