FX-Audio Tube-02 Pro Tube Headphone Amplifier, Vacuum 5725 Tube Preamp, Mini Hi-Fi Integrated Stereo Class A amp Supports 32-600 ohms of Headphones, for Stereo Amplifier/Active Speaker

I've edited my original comments with the adjustments below - edited on 16 February 2022Before I begin, it is always essential to bear in mind that many of these Asian-made (predominantly Chinese made) Head-amp/preamp designs have virtually the exact same interior layouts and components, yet are often packaged differently with slight (or in some cases, major) modified exterior appearances. And with competition being what it is now-a-days, you can find many US companies periodically doing the same thing.Now enter the FX-Audio Tube 02 Pro - a nicely designed tube/class A head-amp/preamp design. After reading over the design parameters and noticing that it's a fairly new release (with only 2 reviews as of this writing), I elected to pull the trigger on one.When it arrived, I noticed a nicely designed unit with an all-metal design. What caught my eye immediately was that it included both 3.5 MM and 6.5 MM headphone inputs (this as opposed to the many similar competing designs that include only a 3.5 MM input). And what was also a positive is the inclusion of two GE designed 6J1 style tubes. You also have an on/off button (which also serves to select your inputs), along with a volume control knob to the right of the front panel. It also has a 2-gain setting button, and what's even nicer (or convenient) is that the gain settings affect headphones only - not the Preamp section. For example, in most headamps/preamps (that have switchable gain settings), adjustments to the gain also impact the line level outputs to speakers. So this is an added feature to have - that is, gain settings impacting headphones only.What is also unique about this particular model head-amp/preamp design is that it includes two Aux RCA inputs - allowing the connection of two different DAC's, if need be, with the option of selecting either one via the front button.After connecting it, I evaluated this unit using 3 different DAC's (not at the same time) - those being the JDS Labs Atom DAC X, the Topping D10S, and the Schiit Audio Modi 3+. As I usually do, I never begin evaluating any listening sessions until I've let the components warm up a bit. I had the FX-Audio Tube 02 Pro on for 24 hours before I began these evaluations. Interconnect cables used were from World's Best Cables and Blue Jeans Cables, with the USB cables being Audioquest Pearl models running from the DAC's to the USB inputs on a professional level desktop PC.Sound Personality: As can be expected, this is a true tube unit, and it imparts a warm, yet very dynamic and detailed sound quality - however, it is just a tad than comparable tube amps in the upper registers. With some DAC's that may have a dry personality, the Tube 02 Pro warms things up and adds a musicality that the DAC (when listening to alone) often lacks. Do keep in mind that other similar tube head-amps/preamps - such as the Douk Audio P1, or the X-Duoo MT-602 - have the same effect. One nice thing about the Tube 02 Pro is that it accurately portrays the sonic signature of different DAC units. If you have a bright sounding DAC, you will experience this added brightness through the Tube 02 Pro.The tubes in the Tube 02 Pro do not run hot at all, especially when you consider other tubed units that use different types of tubes. They never felt warmer than warm - no matter how long I've had the unit on. As an aside, the one tube in the Schiit Vali 2+ runs quite hot (like a heater) as an example. The tubes do light up more brightly in the Tube 02 Pro (at least in this enclosure) because they stick out more towards the top, whereas with competing units, the tubes are more recessed into the enclosure. And because of this design aspect in the Tube 02 Pro, the tubes are easier to remove and switch out (tube rolling). I must add that the stock GE tubes that came with this unit sound superb, and unless you are fixated on wanting to tube roll, you should be quite happy with the result. Now normally, when using these particular GE tubes, the audio typically balances out nicely, with a nice, lush sound. The very slight brightness that I alluded to indicates that the solid end of things has been calibrated to providethe best of both worlds (solid state and tubes).My initial listening sessions were conducted using a variety of speakers connected to a Cambridge AX25 Class AB integrated amp, followed by the Aiyima A07 and A08 class D models. I finished things out with the exemplary Fosi HD-A1 class AB amplifier. The speakers, I then eventually settled upon, were the Wharfedale D320's with a Mackie 8" Powered subwoofer under the desk. I listened to everything on a desktop, near-field environment. Speakers used in this evaluation included the aforementioned Warfedale D320, the KEF Q150, and the self-powered Presonus Eris E5 XT (studio monitors)With speakers, sound-staging was exemplary, and as I briefly mentioned above, well recorded music had a great sense of "immediacy" and "musicality," yet with a very slight elevation of certain frequencies (beginning at around 6000 kHz). But again - keep in mind to allow this amp to warm up/break-in and things will get better as time goes on.Let's face it, there are many "fine" or "good" sounding units out there, but that doesn't mean they have the immediacy and musicality of making you feel like you're at a live performance. Well, this Tube 02 Pro does!!! Of course, an added "no-brainer" qualifier statement is that you should also be using quality components and accessories in your audio chain (DAC, upgraded cables, good amplification, etc.). Just remember that old adage that says, "You can't make chicken salad out of chicken sh_t," if everything else in your audio chain is just so-so.Bass is dynamic and nothing is held back. The midrange and higher frequencies have an almost silky-like quality to them (provided you feed it good audio sources). Imaging, air and depth are all there, to be sure.Now let's talk about the headphone inputs. When you plug in headphones, it automatically shuts off the audio flow to the speakers (I like and prefer that a lot). The headphones that I used included a variety of different HiFiMan planar models on one end, to dynamic units from Phillips, Sennheiser and Koss on the other. The end result was that I found the headphone inputs (audio qualities) to be just a tad elevated in the upper extremes (again from about 6000 kHz upwards). The extra details that you hear through the headphone inputs allow you to hear smaller instruments such as bells, castanets, tambourines, cymbals, and so much more, as they stand out from the rest of the orchestra - when previously, they were hidden among the mix. But this was accomplished by elevating these frequencies, thus making that upper extreme quite noticeable. So the nature of the sound coming from the headphones could be best described as having a distinct V shape, with the upper extremes being elevated at about 6000 kHz and above (again, based on the headphones I used).Overall, after a week of so of use, this FX-Audio Tube 02 Pro Head-amp/Preamp unit really impressed me. It would do perfectly fine as a head-amp or as a preamplifier (especially since it allows you to use two different Aux RCA inputs). The sound qualities compete with the best in this class - and most of this class winds up being a bit more expensive ($100 to around $150 or so, and in some cases higher).Based on it's relatively inexpensive price of $79.95 (at the time of this writing), the design and appearance of the unit, along with its overall sound qualities, I am now giving it 5 starsNow, do keep in mind that like any reviews, all are subjective - and your mileage may vary. My results were based on what I heard, with the gear I heard.Good luck!

Make:Immediately out of the box, you can feel the quality of this little amp with a black matt-finished metal enclosure. An LED on each tube socket shines warm orange glow when the amp is on, which I subjectively love. (The tubes have much dimmer orange glow comparing with the LEDs.) The amp's big volume knob turns smoothly.Feature:It accepts two sources, which can be easily switched by the power button.Sound:This amp sounds beautiful! I mostly listen to classical, jazz or soundtracks. I hear great amount of details with satisfying high and low ends. Violin or soprano sounds brilliant and live while cello sounds sweet and magnetic! There is also sufficient bass so the music feel balanced. I have to say this amp performs quite close to Schiit's Vali 2+, which I have been used for more than 1 year. Given the cost difference ($60 sale vs. $149), this amp's value is incredible!When driving Sony MDR7506 (63 Ohms), 7/8 o'clock is enough for me. (Lowest volume is at around 6:30)When driving Sennheiser HD600 (300 Ohms), 10 o'clock is already quite loud for me. Note max volume is at around 5:30. It will probably smoke the headphones and your ears with max volume. At high gain mode, it sounds a little louder, but it appears unnecessary given the ample output at low gain mode.When the volume is greater than 11 o'clock, I can hear hint of white noises (noticeable, but very little).Remember to keep your phone away from the amp, otherwise you will hear frequent interference.You may certainly roll tubes, but the stock 5725 (GE) tubes are great. The headphone amp is a solid product and I am absolutely happy about the purchase. Recommended!!!

This is a great sounding and cool looking little headphone amp, especially for the price. While I usually leave mine on because I like the glow of the tubes, it can be turned off by holding in the front button on the left.

Got at a good price. Some reviews over the web read pretty good. Didn't really need but I love to try different amps out constantly. As for sound quality, I myself like it. It functions like it is suppose to. Tried with several different brands. Sennhieser HD 570 and one planer from Drop. It matched well with almost everything I plugged in. For the money I spent I'm okay with it.

For the price and quality, it's a great entry level headphone amp. I brought new tubes with the lgv20 and uapp music player app. It's a great way to start this hobby.