ST-01 PRO 200W Bluetooth Amplifier, 2 Channel Vacuum Tube Power Amp with USB DAC/Coaxial Optical Inputs/VU Meter/Treble Bass Control for Home Theater/Stereo Speakers (Upgrade Version)

This is a review of the Douk Audio ST-01 PRO 200W Bluetooth Amplifier. I am a low grade audiophile by my own description--I have spent quite a bit of time listening carefully to the same few tracks on a whole range of components over the last 25 years or so. Engineering background so I take a very pragmatic approach--if I can hear a difference myself then I will consider the costs for better gear across the board. I can't blow money on anything and I don't like to be wasteful so I do a fair bit of research before I buy. This little Douk tube amp has really impressed me! I had an old Denon AVR-5700 home theater receiver that had been demoted over the years to just providing sound for our computer--headphone jack outlet from the computer into the receiver, two passive NHT SB-3 speakers driven by the Denon receiver, and subwoofer line out to one passive NHT W2 subwoofer driven by a dedicated NHT amp. When the Denon died, I needed something to power the same speakers and sub but that's it, just 2.1 channels of sound and not audiophile quality to the Nth degree. There are a whole bunch of these tiny devices out there, I liked this one for its combination of price point, tubes for the two speakers, and subwoofer line out to go to my same NHT dedicated amp for the subwoofer. The size is quite amazing, others have shown the same sort of big ol' receiver that was replaced by this tiny cube--it's really just 4.5"W x 3"H x 6.5"D (from the wall to the front of the dials after I have all the connectors installed). The audio power is also impressive. The claims of 200 W/channel are debatable (another review has very solid points about the power supply and the output claims) and that also will depend on what speakers you are using, where their Ohm ratings will influence the power output. Our computer is in a modest home office sized room, about 10'x12' or so, my two SB-3 speakers are 8 ohms being driven directly by the Douk amplifier via the speaker terminals, and the subwoofer is using the 3.5mm line out to the sub amp, so this little device IS powering my speakers but NOT my subwoofer. When I set it up and started testing with my same old tracks, made some adjustments between the volume on the computer and the volume dial on the Douk, I found that this tiny box can rock this room just fine! I'm impressed with how much bass the Douk pushes to the speakers, which have a very good frequency range themselves, which is nice for most musical circumstances anyway where bass guitars, deeper drum beats, and lower ranges in classical performances get very nicely reproduced. The tone adjustment dials on the Douk are quite nice, recognizing that they are just the two simple dials for bass and treble, so I don't expect them to get any more complicated than that anyway. Between the digital equalizer window on my computer which has 12 bands to work with and the two dials on the Douk, there is quite a bit of refinement you can make to match your personal preference for the types of music you listen to and which parts of that music you prefer to dampen or boost. It's basic but it works well. Like another couple of reviewers, I too received tubes that are much smaller than those shown in the photos on the Amazon product page. However, with a little research it seems that the smaller tubes are most likely an improvement from those pictured. I don't know exactly what those larger tubes are--the product page does suffer from missing details like which tubes are included--but the ones I received are legit General Electric JAN 5725W tubes with "MADE IN USA" printed on the glass tubes themselves, which are mil spec quality (which means they are made to very high quality standards to be accepted for military purposes, back when the military was still using lots of tubes). These are usually offered as an upgrade set of tubes for this Douk so I don't know what happened there but I believe the smaller 5725's are top quality for this level of device. They sound terrific to my ear so I'm delighted with them. I have read way too many subjectively written reviews of the feel and warmth and crispness and all sorts of other floral terms describing how tube amps sound compared to modern transistor-based amps. I don't have two different devices side by side to switch back and forth against each other with every other part of the system being identical so I can legitimately compare point for point the tube am to a transistor amp. Suffice it to say that compared to all of my other experience with transistor amps over these years, this little tube dude sounds fantastic! I haven't had any tube amps before so I will have to see how it performs over time, with things like burn in and eventual failure being known factors, but I don't have the tube testing equipment to test exactly when those thresholds will be crossed, so I'm just gonna enjoy the sound until I hear something wrong. The little ol' analog levels dial with the meter jumping around is quite charming as well. It does give you some useful information, just a basic glimpse into how much or how little you are pushing the power. That feature is a nice little throwback to those old times of analog stereo gear back in the day. And while all you young whippersnappers giggle, you'll also notice how vinyl albums and record players are booming again. There truly is some meaningful, warm charm to having a little visual dial bouncing along to the music with you while you tap your foot and try to concentrate on whatever important task you were supposed to be working on while you jam out, right? Totally gnarly dude (yep, I was in high school in the early 80's, for better and for worse). I am just using the RCA inputs from the computer so I don't have any comments on the other input types that the unit offers. Based on what specs they have provided in terms of formats and frequency ranges, and on my listening experience now with this unit, I would guess that those other input source feeds should work just as well as the RCA input, but that is just a guess. For the money, I am delighted with this Douk, if the need arises I would happily buy another one. Hope that's a helpful review, and hope you get to enjoy your favorite music again like I am!

Edit: Changing from 2 to 5 stars. It was the ac adapter that died, not the unit. I bought this to redo my PC sound setup for music production and also incorporate my tv into the mix with the optical in. Everything went as planned. It sounds great, but I'm coming from a smsl setup so it didn't blow me away or anything. But for the price and additional inputs and the cool aesthetics I was super happy. The remote being a huge huge plus. After a few weeks I watch some YouTube videos after waking up. Everything is great. Go to Hogwarts for a bit. Great. I leave for the day and when I come home it just won't turn on. Nada. Completely dead. I don't smell any magic smoke. Luckily I'm within my return time with Amazon so I don't have to deal with the manufacturer. I'll update this review when my new unit arrives tomorrow. The only thing that I don't like about this amp is what everyone else complains about. It'll go into standby if there is no sound for several seconds. I can deal with that. I don't see what everyone else is talking about with db scale not doing anything. It doesn't on low volume but it does when you turn it up. That's understandable to me. More importantly to me is that the volume goes up and down in notches. So the very lowest volume is still louder than I would like watching stuff at night when I fall asleep. That may just be the way optical comes out of my tv, I'm not sure yet. For the price, aesthetics and integrated DAC, I'm not sure it can be beat.

Sounds pretty good out of the box and can be upgraded with better tubes, external DAC, etc. I have a dozen other amps including the Fosi ZA3, vintage Kenwood and Marrantz, AVRs from Cambridge, Denon, Yamaha, NAD. The built-in DAC isn't great so I use an external DAC that I prefer, it's just the old $20 FIIO Taishan. I go optical out from my TV into the FIIO DAC and then RCA analog into the Douk preamp/amp, which is powering a pair of vintage ADS bookshelf speakers. Recently tried it with my SMSL SU-1 DAC and that was even better. Needed a small form factor to fit the space. Been using it for 18 months, with no issues. The tubes definitely change the sound. It's fun to experiment with different tubes and they're readily available on eBay, often for $20-30 or so for a matched pair. Everyone on Amazon gets the Riverstone Audio JAN 5654W tubes that are marketed as an "upgrade" but I didn't really care for them. Sounded dull and rolled off to my ears. I prefer old soviet-era Voshkod "rocket" tubes. They have a more dynamic hifi sound with extended highs and lows. The VU meter doesn't work very well for me (maybe by speakers are too small/efficient to move the needle at regular listening volume?) but that's kind of a gimmick anyway. Overall worth it for the tube preamp and TI class-D amplifier functions that I use it for. This can be a good option if you like tubes or want to try them out. Also good if you need the digital inputs and Bluetooth built-in, as those are usable if not the greatest.

This adorable little puck is incredible. Set it up with some mid bookshelf speakers like the Polk T15's, and a small but potent sub like the BESTISAN Powered Subwoofer, 6.5'' Side Firing Home Audio Sub; you will have an incredible sounding setup. It will not be loud, but it will amaze you for the price. I use it mostly with my home mac via USB on Spotify with the lossless audio setting. So good you guys. You’ll need some speaker wire and a good long 1/8 inch plug audio cable to put the sub exactly where you want it. I have had a lot of high-end audio setups for many years, and I will tell you that for music alone this relatively low-cost one has impressed me more than any other. Plus, the analog glow of the beautiful VU meter and the solid-feeling knobs on this little guy are just incredible. I love it. 9.5 stars, only knock is no headphone jack which is something I don't need.

I use the unit solely as a preamp into KRK powered studio monitors. I bought it for my record player, but I also use the blue tooth function for playing video/music from the PC. I'm a guitarist and know quite a bit about tube amps, so let me dispel some things others have said in reviews. 1. The tubes are not for looks, they are used in the preamp circuit, one is for left side the other is for right. 2. If you want to use this as a preamp, simply use the aux out jack in the rear to input into your amp or powered speakers. You can also use the power amp functionality if your using passive speakers. 3. The VU meter works perfectly fine. 4. The EQ on the unit work great, HI/Low. very warm sounding unit. 5. The blue tooth function is great, I didn't test the range, but when I switch from RCA (record player) to blue tooth, it connects very fast which is nice. 6. I run the unit in an enclosed cabinet, I have no issues with heat. It's not like a guitar amp that has power tubes, your not gonna get that hot. However I am only using the preamp side, using the amp outputs may generate more heat, but I cant imagine its much. Bang for the buck, this thing is amazing and totally what I needed for the record player. Boosts the signal great and adds warmth, added benefit of blue tooth input. Also, if you want to upgrade the sound (a bit warmer and a bit better volume) update to this model of tubes. I compared side by side, very nice. (5654W) https://www.amazon.com/dp/B01BFJDTW0?ref=ppx_yo2ov_dt_b_fed_asin_title

Three knobs: Volume, Bass, Treble. Guess what - it's all you ever needed. See it atop the unit it replaced - a Sony home theater receiver costing 5 times as much, with its 7+/- channels of surroundoblah - if you can find room to place all the speakers just so. I paired the DOUK with a pair of Polk Audio R40s I found at a thrift store for $20. Oh my, stars, this thing is fantastic. From Phish to Fluke, Movies to Mozart, it just sounds perfect. I've only used bluetooth, paired to my gazillion Apple Music albums, really nothing more is needed. The remote works fine, you can do presets, but really I found one a sweet spot of bass/treble that works great for everything thus. far. Granted, the speakers are good, but this tiny unit puts out a deep, warm tone powerful enough to drive the bass on heavy techno while keeping the treble crisp. When the VU pegs at the top, it distorts, back it down one remote click from there and it'll fill any room with beautiful sound. Do what I did and match it to some sweet old-school speakers, you won't be disappointed. Six stars.

I needed an amplifier for a stereo system in my small home office. For a source, I was planning on using a library of .flac files that I have on a Windows PC. For speakers, I have a vintage pair of Spica TC-50s that I've had since the 1990's. I have a number of vintage tube amplifiers in storage, but most of them have been stored for decades, and would require some work to bring them back to life. Also, I really didn't want to use something that would use a lot of electricity and generate a lot of heat. So, I decided to give this tiny Douk Audio integrated amp a try. First impression out of the box was that this tiny amp sounded OK - mostly like a generic solid-state amp, like one you'd use in a car stereo. It really didn't have any of the imaging, or the smooth, lush midrange that you get out of a good tube amplifier. To me, voices and instruments sounded a bit harsh and artificial, without any of the tonality that you hear when you listen to live acoustic instruments. So, as a last resort before using this amp to replace the boom-box I have in the garage, I decided to do some tube rolling. My hopes weren't too high - the tubes are onIy being used as buffers between the preamp and amp stages, not in the amplification stages themselves. I replaced the GE JAN 5725W tubes that came in the amp with a pair of Voshkod 6ZH1P-EV tubes. To my surprise, it was much better! The midrange smoothed out, female voices sounded more real, not harsh and brassy. There are still a lot of problems, though. The bass isn't as tonal and well-defined as I would like. The top end (like hi-hat work) isn't crisp and clear - when the drummer taps out a rhythm on the cymbal, you don't get the tonal variations when he hits different areas on the cymbal. I don't know if these issues are in the actual amplification section, or if they're being caused by the conversion from the digital signal coming in via the USB port to the preamp. In any case, I don't think there's a whole lot that can be done to remedy these problems. Anyway, with the change in tubes, it's good enough for use in my office. In fact, its imperfections may be a blessing - I've had really good systems in previous offices, but the better the sound, the more I found myself being sucked into the music instead of concentrating on what I was doing. And, with the library on my music PC set to random autoplay, I'm having a lot of fun hearing B-sides and other tracks that I haven't heard in years!

I cannot believe how good this sounds paired with Polk Audio T15 Home Theater and Stereo Bookshelf Speakers. This setup works great with a bunch of computers via a passive audio switch. Did I mention the awesome amazing sound? This is a very flexible and amazing amplifier. I wish I had bought one long before this! It sounds great, it looks great, and it is worth every penny. Thank You Douk Audio!

I thought "I'll try this gimmick, I will likely need to buy something way more expensive but let's see what it's like". Three Months later I've kept it and have no inclination to buy anything more expensive. For the price this performs amazingly. It looks like its a toy, the tubes are pathetically small and Im not 100% sure they do anything other than look good. (If they are working its in a Starved-Plate mode, real tube or valve amps need hundreds of volts on the anode to work properly). But the litmus test is "how does it sound", and it sounds great! It's replacing my "Natural Sound" Yamaha Bluetooth AV Receiver (RXV385 B) that I bought in 2018. There is no comparison... this pokey little piece of gear runs rings around the Yamaha. Re: the "200W" designation, It's more likely 100W peak per channel, the likely RMS is probably/possibly/maybe closer to 50W into 4 ohms, or perhaps 25W into 8 ohms. It's certainly loud enough for my smallish living room. I run the unit using the inbuilt D/A via USB from an intel computer, it's driving a pair of JBL 8" N28 Northridge speakers and also my Beyerdynamic BT770 headphones. So far everyone that's heard it (from "technical types" to non technical "music lovers") all think its a significant improvement and use words like "clear, balanced, wam, clean". Does it sound as good as my Creek CAS 4040 S2 did or my dads old Williamson class A tube amp that ran at 450Vdc? No. You get what you pay for, but for me, to get something sounding significantly better costs more than I think I need to spend given how good this actually performs in the manner I use it for. (Streaming Movies and or music concerts). Maybe they use some algorithm to simulate a little tube harmonic distortion, maybe the tubes actually do add tonal significance, maybe we imagine it because we see tubes and think it must sound different? Who knows, but at this price who cares. (Some people who heard it didn't even know it was the amp so the cognitive bias argument doesn't necessarily hold up). Bottom line? Im super happy and plan to stick with this. It unexpectedly good and what you get for the money seems wonderful so far.

This little Tube Amplifier’s sound quality is amazing. I connect my HiFi system equalizer and CD player to this Amp, it’s handling the Quality of sound. Very impressed with this Tube Amplifier. Recommend it.

Great sound

For the size and attached to small Bose speakers is amazingly good quality + looks very cool!

It is amazing what a nice sound this little thing can provide. Especially I like warmth of the sound (kind of softness) produced by tubes. Pair it with Polk's speakers (like I did) and you would just "bath" in music all day long.