September 26, 2025
#520
Gentle reader,
I am very excited to be the very first person to review Douk Audio's new DJ587 Tube Stereo Power Amplifier. To my knowledge it is their very first tubes-only power amplifier and I am delighted to have one and to be able to tell you all about it!
To research this article, obviously I looked for any and all information about the DJ587. What did I find? Absolutely nothing! Their eBay auction does show specifications for the amp, but, the amplifier itself is devoid of any markings or labels of any kind. Were it not for the schematic which they included, I would not know what goes where into and out of the amp. It seems like they rushed it to market to see if anyone buys them and then will market them more effectively.
The DJ587 is being sold via eBay by Douk Audio's subsidiary Nobsound. It is available in both KIT form and fully assembled. Since it has been fifty years since I built my very first real piece of stereo equipment in kit form, a Dynaco PAT-5 preamp, and I have never built anything which uses tubes instead of transistors, I chose to pay a bit more to get it factory assembled. Below are the photos Douk Audio uses in their eBay auctions for the DJ587 Tube Power Amplifier:
This and the following six images are courtesy of Douk Audio.
As you can see, compared to 20th Century tube power amplifiers, it is very sparse beneath the top cover.
Since I have been a solid-state (transistors, not tubes) equipment person since the beginning, the only other tube equipment I have tried out is an Aimiya T2 as a tube buffer. I wrote about it here: The Robb Collections: Review of AIYIMA T2 6K4 Tube Preamplifier Can this Solid Little Asian Beauty Sing?
To make sure that it still works, I connected it between my B&K Components PRO10 preamplifier and it's matching ST1400 power amplifier. Sort of as a "tube buffer". It worked fine, so, my next step in this review was connecting my SONY CAR Discman CD player to the T2 and the T2 to the DJ587. Why? So that I would have the most tube-only path from the source to the speakers in order to try and tell if there anything to the "Tube Warmth" others have spoken of.
The AIYIMA T2 from above. I could do without the blue LEDs. Red cover is over the Bluetooth antenna connector.
As I mentioned above, the lack of markings or labels was solved by the schematic. Tube powered equipment, back in the day, had up to three choices of speaker terminals for speakers with: 4, 8 or 16 Ohms impedance.
While not obvious, a close look (by clicking or tapping the image) will reveal that all seven tubes are glowing orange.
"Warm tips
1. DIY KIT version (without power cord) requires some welding ability to solder, and we do not provide step-by-step guidance. Otherwise, please consider purchasing the finished version (with power cord).
2. Due to the scarcity of vacuum tubes and the instability of inventory, the actual shipment will be replaced with different types of tubes and components according to the actual situation. All replacement is of the same level, and there is no difference in function and effect.
Features
- Reasonable tube design: choosing 6N2 and 6P1 vacuum tubes to amplify the signal and power, and 6Z4 as rectifier tube. Each tube has been tested to ensure good performance. Pluggable tube design provides much more playability.
- Pure audio experience: adopting single-ended circuit, working status remains class A and output power is 4W+4W. Superior sound quality, and excellent transient response, providing a premium audio experience with reliability and efficiency.
- Exquisite craftsmanship: Handcrafted point-to-point wiring ensures superior sound quality, customization, and a unique aesthetic appeal, making it an ideal choice for audiophiles seeking the best listening experience.
- Stylish enclosure design: boasting a brushed stainless steel chassis for durability and a galvanized iron plate baseboard with CNC-punched rectangular holes for optimal heat dissipation, ensures both style and performance.
Warm tips
1. DIY KIT version (without power cord) requires some welding ability to solder, and we do not provide step-by-step guidance. Otherwise, please consider purchasing the finished version (with power cord).
2. Due to the scarcity of vacuum tubes and the instability of inventory, the actual shipment will be replaced with different types of tubes and components according to the actual situation. All replacement is of the same level, and there is no difference in function and effect.
Features
- Reasonable tube design: choosing 6N2 and 6P1 vacuum tubes to amplify the signal and power, and 6Z4 as rectifier tube. Each tube has been tested to ensure good performance. Pluggable tube design provides much more playability.
- Pure audio experience: adopting single-ended circuit, working status remains class A and output power is 4W+4W. Superior sound quality, and excellent transient response, providing a premium audio experience with reliability and efficiency.
- Exquisite craftsmanship: Handcrafted point-to-point wiring ensures superior sound quality, customization, and a unique aesthetic appeal, making it an ideal choice for audiophiles seeking the best listening experience.
- Stylish enclosure design: boasting a brushed stainless steel chassis for durability and a galvanized iron plate baseboard with CNC-punched rectangular holes for optimal heat dissipation, ensures both style and performance.
Parameters
- Audio input: Stereo RCA
- Audio output: Banana speaker jacks
- Output power: 4W*2
- Suitable speakers sensitivity: ＞90dB
- Frequency response: 20Hz-20KHz
- Input voltage: 100-120V / 220V-240V, 50HZ/60HZ
- Main transformer power: 75W
- Output impedence:4Ω / 8Ω
- Power transformer: 76*50
- Output transformer: 5k, 66*32, 8W
- Dimensions: 328*176*52mm / 12.9*6.92*2.04in
- Net weight: 4.5kg / 9.92lb
- Package weight: 5.5kg / 12.12lb
Packing List
- 1*DIY Kit / Finished version (optional)
- 1*Power cord (only for finished version)
I have already removed some of the soft Styrofoam packaging at this point.
So, does that mean that I recommend that everyone who wants to see what this resurgence of antiquated Tube audio equipment is all about fork over their $219 USD and get one too? No, it does not. I think I have made it clear: You MUST have high efficiency speakers which have a tested efficiency of 90dB or higher. Otherwise, you WILL be disappointed. You have been warned. 
To conclude: IF you DO have high efficiency speakers AND you and your family will not suffer because, "Scott Robb raved about this inexpensive tube amplifier and I just HAVE to get one!" Then, by all means, order one. Heck, if you have experience soldering, buy the kit and save a few dollars.
So far, so good. Three transformers. The left one converts house current ("mains" for my UK readers) to the voltage the amplifier needs. The other two convert the high voltage tubes use down to what speakers can handle, which is not a lot.
The transformers are the bulk of the weight. Note, no markings of any kind. Anywhere.
Two pair of RCA inputs, which is nice and in my experience, unusual. Again, thanks to the schematic and LACK of labels, I knew to use the outer red speaker terminals for my 8 Ohm speakers. Note IEC power socket so that one can use quality power cables. 
Nicely finished and perforated steel bottom cover and sturdy feet. The unit is surprisingly heavy for it's size. A mark of quality. The heavier the transformer, the higher the speaker output power.
The tubes safely wrapped in bubble wrap and what is actually yellow tape. The brown box makes it appear brown.
Once again, thanks to the eBay web page, I knew which socket the shorter fatter tube was designed for. Another "interesting quirk and feature" I'm channeling Doug Demuro here, is a volume knob. 
An overhead shot without all the glare. My Lumix LX7 digital camera has a fast Leica lens with a maximum aperture of f1.4, which makes this shot possible without flash.
A full sized scan of the included schematic of the amplifier. A buddy pointed out that Douk Audio chose to use a tube to rectify the amplifier. I have no idea what that means. I was not a tube person. But, I sure AM now!
I have made these two brochure photos large to make it easier to see all of their many products.
Now, I want to make one thing perfectly clear: I do NOT get paid by anyone to write reviews. I BUY the products at full price and review them as the OWNER of the product.
With that being said, here are my thoughts on this new Douk Audio Class A DJ587 4wpc Tube power amplifier: IF you have quality high sensitivity (the higher the dB number the speaker manufacturer supplies) 90dB or greater, you WILL be happy with the sound of this amazing little amplifier. I am sold on tubes now. It took me fifty years, but I finally get it!
If I had room for a real Tube preamplifier, the AIYIMA T2 is more of a novelty than a serious preamplifier, I would be in the market for one. 
This is a photo I shot, with a 10mm lens on my Nikon D300 DSLR camera, of the listening room. First off, I am not a "gun lover" or a hunter. I am the opposite of that! The rifle does not work. It is missing it's firing pin and the maker went out of business a LONG time ago. Secondly, the Jackelope is a fictitious animal, my ever-loving wife bought it for me. Thirdly, the cat skin was purchased by a dear friend many years before I met him in Thailand. It is from a Fishing Cat. Yes, there are such animals, look it up. If you look closely, you can see my B&K ST1400 power amplifier in front of the record shelf.
This is a photo of my stereo system. I have been in this hobby since 1975. Yes, for fifty years. I know what sounds good and what does not. I can unequivocally say that Douk Audio's DJ587 Class A Tube Power amplifier, through my Dynaco A25XL high-efficiency speakers sounds FANTASTIC! No ifs, ands or buts. I LOVE the way this low powered simple beauty looks and sounds. I have yet to detect ANY distortion at all. NONE.
Thank you for taking the time to read my article on this miraculous little (and heavy) tube power amplifier. Again, I do this for FREE, no one pays me anything to write. Feel free to leave a comment below or via Facebook.
I write two other blogs, but have not worked on either for a while. I need to get back to them. Pictures of Nancy. The Love of My Life. And: People Say I'm Special. But I Don't Know Why
Scott Robb
September 26, 2025
#520
PS Every Robb Collections article is available. Just keep scrolling down and down and down after this sentence. At least they are on a PC.
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