Douk Audio 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)

Great little amp. Sounds great, lots of input options and has tone controls. Remote included is well made and works perfectly.

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.

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!

Great sound

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.