Douk Audio U3 Headphone Amplifier

Does exactly what it says, for the amount you want to pay

It is exactly what I was looking for in the price range I was willing to pay. It doesn't have the greatest audio quality, as it's only a class A amp. But for my purposes it's fine. I use it to convert the line level out from a mixer that is fed by three different HF radios into a seven watt speaker. Given the bandwidth of my radios and the quality of the audio from a radio, it works just fine. I would expect for music it would result in some appreciable loss of audio quality. When I transmit, there is quite a bit of RF in the area, but it does not amplify that and performs just as it should. Note it's location in the photo behind the mixer, that was all I had. But this indicates a use case scenario.

Obviously this thing is designed for headphones, but for one 7 watt speaker, It has very good audio and is very loud. But I never take the volume up past about 50%. It's loud enough and I don't need to.

A Nice Amp

I used this amp in combination with a modestly priced speaker bar to amplify my TV sound. I had a smart speaker but it would automatically shut off after a period of time and it needed its own remote to turn it back on, adjust volume or mute.

I wanted a plug it in and forget it type of solution. So, using this amp and a cheap speaker bar I channel the audio out from the TV through the amp and then the amplified output to the speaker.

Both the speaker and amp are USB powered so I just plug them both into a USB enabled outlet. I like this amp because it doesn't have an internal power supply so I can leave it plugged in indefinitely.

Great bang for the buck headphone amp

This amp is very good for the price, I connected my 300Ω Sennheiser HD 540 Reference headphones and they were loud and clear. It also works with 32Ω headphones. I will say that if you turn the amp's volume too high it will have a quiet hum, nothing too bad though. It was quite easy to set up and it's nice and compact.

EDIT: The hum is due to using my computer's USB port for power. To prevent any noise or humming, use an external USB power brick.

It's pretty good

Sounds good, and has a very flat response when I measured it with Arta and my sound card, with 32Ω headphones connected. Can't speak for higher headphone impedances, as I do not currently have any such headphones. The hiss is only noticeable without input and when you have it set so loud that if the signal was there, you would probably destroy your headphones or ears. And that's with an USB charger (I used a 2.5A charger that came with my Hantek oscilloscope and is pretty noise-free). It has nice build quality. Now for the disadvantages. The included 6.3mm to 3.5mm adapter, that doesn't have a very good ground connection especially if you have headphones with a microphone. The power button is on the back, so you can't have it neatly in between your other audio gear - a switch in the knob or on the front panel would be much more convenient. The volume pot has detents, which limits the volume setting accuracy and is annoying (you can probably replace it though, as the whole device is easily serviceable and it doesn't seem to be an unusual pot shape). The power LED is blue and annoyingly bright, so you will want to turn it off when you are not using it, especially if you sleep in the same room. Again, something that I will probably modify in the future. It makes a loud noise in the headphones as it is powered down, so you probably should unplug the headphones first and then turn it off, especially wit IEMs that might possibly be damaged by this.

Well built amp. Quiet. Sounds good.

This amp sounds great powered by 13 volt RV battery. It will drive my inefficient closed back phones up to dangerous level before clip. The basic op amp was easily upgraded to LM 4562AN with a #0 phillips and a 2mm hex wrench. LM 4562 ic is a $7, 100% upgrade. Stock ic had little musical ambience and its higher gain made me use bottom ccw part of the volume control. Pianos dont lie.

Btw, that volume pot was missing its proper hex nut to secure it to gold faceplate. This is not good. Hence only 4 stars. No leaving out necessary parts!

Metal chassis keeps out noise. All connectors are tight. Only intermittent was the supplied phone jack adaptor. Using AKG adaptor all is solid.

Will buy again.

Love this amp

Love this amp. it puts out great sound. drives my Sennheiser HD620S headphones. excellent smooth sound. Extra clear clean bass. Crispy highs. My only gripe... I wish it had optical input.

I still love it with RCA cables

Its good

Its a great piece. It drives my 80ohm audiophile headphones and the playback is clear, quiet, and comfortable. The volume nob doesn't feel great but it functional and causes no extra issues. The whole thing is pretty versatile considering its simplicity; it just has the RCA inputs in the back which can be connected to anything with a preamp, including my Fluance record player and JVC Cassette deck. Its nice that it runs with USB power, but the power cable is pretty short and you don't get an adapter, so make sure you have that. The 6.35mm jack adapter works well and is pretty useful on its own too. Overall, great piece for a casual listener.

Very SOLID For DT 770 80 Ohm

I had my DT 770 80 Ohm headphone connected to my Scarlett 2i2 3rd gen, while it is "Kinda" fine when listening to music, I do think it is lacking a bit of volume specially when playing games.

The Douk U3 did help alot in term of volume. Much more headroom that I ever gonna need.

There is a very and I mean VERY minimal hssing sound when nothing is playing . But once you start listening to music or play games, you wont be hearing it at all.

It can use anything from 5V to 20V to power it up. I personally use a 19v power brick that I had around, without any sort of issues.

For the price, THIS is a very solid deal. Specially if you need some extra volume headroom.

Excellent Audio Amplifier (Douk U3) for my Dell Windows 11 PC from Samsung Monitor headphone Jack

I bought a new PC a few months ago and had just been using the audio output headphone jack of my Samsung monitor then to regular desktop speakers (Logitech). It was working ok until I was watching a lot of live legislature streaming and I was struggling to hear it. So instead of doing something more involved on an alternative audio device, I elected to get this mini amplifier (monitor headphone jack ->amp->speakers) and it works really well. I can set the power level low and just turn it up when I need to.

Great AMP!

Great unit for the price! Works great for my headset and the audio is nice.

Awesome amp board if you're willing to work

U3 :

For $40 bucks this amp is really good. However there is a good amount of line noise. Replacing the stock JWCO capacitors with some Nichicon golds takes all of the in out of the line and makes this thing punch well above it's price range. However the capacitors are a bit too tall so you will have to modify the chassis a bit. Even with the open top there is no line noise even when plugged into the USB on a computer.

I will be making an acrylic lid for the amp but for now it looks pretty cool open topped. Probably gonna buy a second for travel.

Would recommend, 4 stars just because of factory line hum.

If you're replacing capacitors

470uf x 35V *5

470uf x 25V *2

47uf x 25V *2

Great setup

I needed power for my Audeze lcd-x (2021), bluesound node n130 great dac, douk audio u3 great for power! Be sure to put 20v for best quality.

Casey

February 2, 2023

Compact Powerhouse: The Douk Audio U3 Amp Surprises!

I recently purchased the Douk Audio U3 Mini Hi-Fi Amplifier for my home audio setup, and I must say, it's a delightful surprise in a small package! Right out of the box, the build quality impressed me - it feels sturdy and well-crafted, a testament to the thoughtful design.

The setup was a breeze. I connected it to my audio system and headphones in no time, without needing to refer to the manual. The simplicity of its design is a big plus for anyone who wants a plug-and-play experience.

Now, let's talk about the sound. The U3 truly shines here. It provides a crisp, clear amplification that has breathed new life into my music collection. The bass is punchy without being overpowering, the mids are beautifully balanced, and the highs are crystal clear. It's remarkable how this little amp can handle a wide range of genres effortlessly.

What I love most is its portability. It's compact enough to fit in the palm of your hand, making it perfect for a small desk setup or for taking on the go. Despite its size, the U3 packs a punch and rivals the performance of larger, more expensive amps.

In conclusion, the Douk Audio U3 Mini Hi-Fi Amplifier is a fantastic buy. It offers excellent sound quality, a user-friendly experience, and great value for money. Whether you're an audiophile or just someone who appreciates good music, this little gem won't disappoint. Highly recommended! 🎶👍

The way to power is better to use not a laptop, but through an adapter in a socket.

When you connect the amplifier via USB to the laptop there is a soft noise. I plugged it in through the phone adapter to the socket after that the noise disappeared. I don't know if I can do this or not, but the noise is gone. The amplifier is good. The result, yes, the amplifier is very compact and everything is assembled with high quality, I am not an experienced amplifier user, but I like it. Thank you.

Little but mighty!!

So I bought this little thing and it turned out to be the biggest win!! Im listening on headphones to my music on my setup and its pretty sweet. I highly recommend the purchase!

A fun HA to roll op amps am play with. Good, but not great. Very power supply dependent.

Bottom line: with some effort, this headphone amplifier is fun to play with and roll op amps through.

But, before you get to have fun, you need to have a dead quiet power supply. I wish the PSRR (Power Supply Rejection Ratio) was published. This amplifier will amplify everything, including any hum or hiss your power supply lets through. Don't bother trying to power this from your computer's USB ports; both hum and hiss will be very audible.

Even with a name brand well regulated USB power supply, hiss will be audible. If you know what defects to listen for, you will hear them. If you don't know what to listen for, you will hear them also, you just won't know what the name of the noise is.

I have found that when this is Headphone Amp is hooked up to a dead quiet power supply, it is enjoyable. Subtle differences can be heard in different op amps. The op amp socket makes rolling a breeze.

Unfortunately, the only PSU that I have found to be quiet enough to enjoy this amps extreme sensitivity has been a sealed lead acid 12 volt 12 amp hour battery. This is probably not a viable solution for most users, but it will provide a very "black" background free of noise.

I would also love to know the gain of the op amp circuit, as some of my more favorite op amps are not unity gain stable.

Along with rolling op amps, I also changed out all of the stock JWCO capacitors for some Nichicon and Elna counterparts. I can't attest to any "auditory revelations" from doing this, but I did not put much time into trying to listen too hard for a good before and after reference. I do trust Nichicon and Elna, and while I haven't personally had a bad experience with JWCO capacitors, I have read of many. Besides, desoldering can be a great form of zen meditation.

All in all, this little amp is a good (to almost great) value for what it is. But if you are seeking a sublime critical listening experience, prepare to put some effort in.

Works well with 4 way mixer

I bought the "Little Bear (Douk Audio) 4-way mixer" and noticed a significant loss in audio volume. I purchased this after about a week of "research." This worked really well. PRO-TIP: I turned each of the individual mixer nobs to about 75% to avoid any background noise. I'm not an audiophile but I can tell a significant boost in bass and clarity as well. I haven't tried any other amps but this worked for me.

Great sound, quality build

Very impressed with the quality sound and build of this little headphone amp. In terms of power supply, I just plugged it into a laptop USB and it sounded great. The amount of volume available is more than I'll ever need. I turned it up to about the 10 o'clock position and even with fairly power-hungry Grado Labs headphones it was louder than I could stand for any length of time. Seemed to really pump up the bottom end on my Grados. Very happy with this purchase.

buy it already !!!

this was a life saver, i needed an amp for my 250 ohm headphones and this made it happen! sound is amazing , i even tried it with my hyper x cloud 2 headset which is a 60 ohm set and they sound wayyyy different (nothing against the hyper x amp card ) but this changed the game for all of my headsets! And for just $35 i got it with a coupon woulda gladly paid $70 for it

Genuinely shocked

Unlike the preamp you see on top, this makes a huge difference in my beginner setup. For 30 some odd bucks I can actually use my 42 ohm headphones to listen to vinyl at max volume and have a fantastic soundstage when mixing audio on my PC. I really haven’t noticed and audio discrepancies, and from other reviews it looks like I got the only functional model they sell.

Genuinely surprised by this device, can’t believe how much it actually worked

Awesome little amp

I paired this amp with my AT-LP60 turntable and DT 770 pro 80 ohm headphones as an upgrade from logitech "thx" speakers, out of the box I immediately chopped the USB cable end and added a proper 12v 2A supply, zero hiss both at zero and max gain.

The gain knob rubbed a little with the case making it a bit rough, this was easily solved by pulling the knob itself out about 2mm.

When turning on and off there is definitely noise and crackles but that's expected, it takes about 4 seconds for the unit to turn on completely.

Overall perfect for my needs, the only thing I would change is the blue led, maybe i'll add a resistor as it is very bright!