ST-01 PRO 200W Hifi Valve Amplifier, Mini Tube Amp, Stereo Receiver, 2 Channel, Bluetooth 5.0, Audio Digital Amplifier for Home Passive Speakers, with VU Meter, USB DAC COAX/OPT

Update 7th August 2023: Absolutely zero issues thus far and continues to handle anything I throw at it with ease. I don't see a reason to upgrade for a little while! Original review below. --- As a relative newcomer to Hifi audio, choosing an amplifier was difficult, but ultimately I decided to spend a bit more than I was expecting and ended up with the Douk Audio ST-01 Pro. This review details the sound quality and how it responds in some different genres of music. Paired with a lively pair of Klipsch R-51M speakers, the amplifier is quite literally a perfect match. Despite Klipsch being known for having quite harsh treble, these speakers were tamed thanks in part to the tubes, giving music a rich, warm sound. And contrary to the unverified one star review, they DO work as unplugging one tube will yield no sound output. The tubes essentially act like a filter, before the output is fed into the chip amplifier. The tube lights are purely cosmetic from small LEDs on the circuit board underneath, however. The overall build quality is fantastic for a product at this price point: a steel enclosure with firm rotary knobs on the front, solid connections on the rear and a vintage sound meter lets this amplifier look so genuine on my floating shelf. The Pro version allows the sensitivity of the sound meter to be adjusted on the underside, but you really have to crank the volume loud for it to really move, even on its most sensitive setting; we're talking 75 dB kind of loud, which in the bedroom my Hifi setup is in is totally overkill and can be heard throughout the house and likely next-door. To clarify a point many will ask, the clicking sound is still present in the Pro version and is designed to disconnect the tubes when no audio is playing after 10 seconds to improve their longevity. If you're playing audio relatively non-stop however, this shouldn't be an issue, but it can be turned off nonetheless by pressing M1 on the remote it ships with. Therefore, a word of caution: don't lose the remote! Now onto sound quality and first: treble. Everything is clear and accurate through my Klipsch speakers, though I do prefer a little extra shine on my music and the +-6 dB treble EQ knob works very well here. There isn't any harshness as a result of the tubes and I can't perceive any particular peak in the frequency response. The mids have no trouble allowing vocals to step forward, too. My previous system struggled with ABBA's Don't Shut Me Down as an example, but the amplifier allows crucial elements of music to be positioned where they matter. I thought at this price point I'd be longing for more, but if anything it has exceeded my expectations of articulation in all tracks I've heard. Bass is slightly harder to review here; I'm limited by the Klipsch's 62-21k +-3 dB frequency response which isn't as bad as it sounds, but smaller speakers at higher price points can go much further down as a comparison. The room I'm in is also bordering on a cube shape, which is absolutely horrendous for bass acoustics. Still, I can hear a good bass response sitting/lying on my bed near the wall, and it is glorious. Nothing sounds particularly muddy or lost, though I think turning the bass EQ above 3 o'clock is a big no-no. It drives warmth and punch into the mix whilst not overpowering any particular genre of music. I touched on soundstage with ABBA in the mids, and whilst I believe the Klipsch speakers are responsible for the majority of this particular sound quality, the amplifier ensures everything has its place and has even allowed me to hear new things in my favourite tracks I barely knew were there, but I definitely think there's more depth to be had and spending more is the only way that's going to happen. Stereo imaging is equally impressive: I'm able to easily place instruments and vocals between the speakers and hear my music in a new light; some elements I can't even trace to the speakers, it's that good. Again, the speakers can probably claim most of this trait but the amplifier has a job of allowing the speakers to perform in the first instance. I've listened to a lot of music through these speakers and I've been impressed by nearly all of it: • Uplifting progressive house is beautiful thanks to the rounded treble and mid response, allowing acappelas, synths and high-hats to shine through. • Pop is exciting and fun, especially with songs with orchestral elements. (Sweden's 2022 Eurovision entry Hold Me Closer by Cornelia Jakobs is an excellent example.) Bass-heavy party tracks are lacking in the low frequency department but I've already explained why this is so above. • 80s tracks hold up well here too; my mother loves listening to George Michael and the like. • Dream pop and shoegaze tracks mean I can enjoy 3-5 electric guitars flowing with the vocals, and they are in the right positions no problem at all. This is a good soundstage test as the vocals aren't always supposed to be at the front of a song. • I've yet to try other genres I enjoy such as rock and metal, Eurobeat, phonk, electronic and jazz, but I plan to update this review down the road. Trance is also a big genre for me, but I'd imagine this is covered well by my love for uplifting progressive house. My family have listened to their favourite music and have all thoroughly enjoyed the sights and sounds of the Douk Audio ST-01 Pro, despite the fact they all have hearing difficulties to some degree... My plan of attack now is to explore my vinyl collection and begin DJing with house vinyl records (yes, without monitor speakers), and again I will update a few months from now. To add, I'm doubting this unit will fail or give me any trouble given the joy it has brought thus far, but given its Chinese origins I can never be sure. I'll be sure to update this review of the worst happens, however. Lastly, I want to note that Bluetooth connectivity has not been an issue at all for me. I have noticed that if Bluetooth is turned off before I switch the amplifier on and then enable Bluetooth on my phone, I have to connect manually. Switch Bluetooth on before the amplifier has power, and Bluetooth connects automatically without hassle. I really like this connection method given I use my old phone for my tunes, but your mileage may vary. Additionally, a Bluetooth connection generates a quiet mid-pitched hum which can be heard during quiet passages of play and between songs. This doesn't bother me much but it's something to be mindful of. I think it's safe after reading my review I speak highly of this amplifier. It has unlocked a new world of audio for me and I know this will be engraved as an essential piece of kit I owned in my early days of HiFi audio. I can firmly recommend this to anybody doubting whether those extra few pennies are really worth it over the most popular chip-powered amplifiers, because let me tell you: the ST-01 Pro has been worth every penny so far.

Holding this in your hands, oozes quality and style. It has weight to it. It looks great. It does what it supposed to do. I just love the meter. The valve light is dim, not really noticeable unless quite dark. I have 8ohm impedance speakers, which should mean the amp is working less according to the information. But the amp seems to get very warm. I have set up a small PC fan to help with this as it does concern me. That said, it drives the drivers and delivers good, crisp, resonating sound. Love the retro feel and look. Love the sound. Bluetooth is easy and connects, literally, just like that, switch the amp to BT and connect your device. It does want I want it to do and does it well, so far anyway...very pleased.

Douk Audio ST-01 Pro - Impressive little Amp !!! I purchased the Douk Audio ST-01 Pro after returning a Fosi MC331 Amplifier, which suffered low-volume cut-out issues. It was purchased to be used with a pair of Tibo Plus3 Speakers. The Speakers had initially been active, but developed problems, so I removed the internal amplification, leaving a passive pair of 4Ω Speakers. Until the fault developed, I had always been pleased with the performance of the Active Tibo Speakers. I’m very impressed by this little Amplifier. I don’t tend to believe the output claims of such budget equipment, but it can play far louder than I require, without any hint of distortion. I’d always found the Tibo’s (when active), required the Bass & Treble slightly turned-up to obtain the best sound, however, with the Douk Amp there is no need for such adjustment. The sound is full, crisp, lively, and gives good instrument separation, with a healthy ‘Bass-Drum’ kick. Although I can’t make direct comparison, I certainly believe that the Douk Amp produces far better audio performance from the (now passive) Tibo speakers, than was achieved with their own original inbuilt amplification. I should add that this little system resides in my dining room, so isn’t my primary listening source, nor is it set up for a critical ‘Stereo’ soundstage, however, for a trial, I did set it up in my living room, which allowed it to ‘stretch its legs’ admirably, rather than reveal any imitations… The ST-01 Pro features an ‘Auto Mute’ option (selectable via Remote), that puts the Amp into ‘Mute Mode’ if there is no input signal for 10 seconds. I wondered if this mode may give rise to similar low-volume cut-out problems that I encountered with the Fosi MC331… However, with ‘Mute’ mode selected, I haven’t been able to notice any adverse effects when playing music, it will play down to minimum level, and I haven’t found it to be affected by track fade-outs, (as most fade-outs don’t approach 10s in length). There’s no actual indication as to whether ‘Mute Mode’ is selected, other than pausing your music, and wait for the little Relay-click after 10s, then another click on resuming playing. If there’s no click, then you’re not in ‘Mute Mode’. Aside from the ‘low-volume cut-out’ issue that led to my return of the Fosi MC331 Amp, I actually found their audio performance virtually identical. Since both Amps share a similar aesthetic, price, and large array of inputs, I thought it may be worth me mentioning a couple of other issues, as relate to the two amplifiers. The Fosi MC331 has a headphone socket, whereas, the Douk ST-01 Pro does not. The Fosi Remote features buttons for Bass & Treble adjustment, the Douk does not. The VU Meter on the Douk has a little adjustment potentiometer (underside of Amp) to allow adjustment of the Needle sensitivity, but please be aware that a decent volume is still required to achieve much movement. The Fosi doesn’t have such adjustment, so Needle movement is minimal unless really cranked-up. The Input Markings on the Douk have larger and bolder text than the Fosi, also the LEDs are larger & brighter, making visual selection easier. My initial purchase was based on the visual appeal of the Fosi, which I considered to have a more refined appearance, particularly with the glass tubes protecting the Tubes. However, from a performance perspective, especially if you may listen at low volumes, the Douk ST-01 Pro is very much the safer bet. I’ve left a separate review on the Fosi MC331 which gives more detail of its issues. In my attached photos, the Douk sits on top of a full size Technics CD Player between my Tibo Speakers, and is flanked by a pair of Fosi Music Visualisers. You may notice that the Tubes in my Amp are shorter than shown in Douk’s promotional photos. -------------------------------------------- I HAD TO RETURN MY FIRST DOUK ST-01 PRO AMP. My first Douk ST-01 Amp emitted a low-frequency hum when first switched on, which lasted faded to silence after approx. 8 seconds. If the Amp was switched back off and back on within a few seconds the hum would be less, as it seemed to relate to the Valves warming-up. As a test I switched-off, removed the Valves and switched back on with valves still removed…, in this state, the hum was now constant. The hum, although very noticeable, was at a volume below typical listening volume. It wasn’t affected by position of the Volume Control, but was affected by Bass & Treble. I returned this Amp to Amazon and ordered direct replacement, which shows no sign of this issue…, hopefully I was just unlucky with the first Amp. My ‘4-Star’ review is impacted by the fact that my first Amp had a problem, and also to reflect the fact that impressions of Audio Equipment tend to be personally subjective. I’m not an audiophile, but I do have a critical ear, and can certainly tell when something inspires you to hunt out your favourite music to re-listen. My comments are in relation to the this being a ‘budget’ system.