Douk AudioP1 Vacuum Tube Bluetooth Preamplifier, GE5654 Audio Preamp, Hi-Fi Headphone Amp, Stereo Wireless Receiver with USB DAC & APTX-HD for Home Theater Amplifier/Active Speaker

Update (18Oct2023): I am rethinking my claim on the tubes being the problem during my initial review. Today, I was taking an inventory of headphones and IEMs and listing to some while I built the list. What I found was any headphones that have the TRRS for headphone cables with a built-in microphone, the DUOK 3.5mm connector seems to let the cable insert a mm or so too far which results in the same poor sound quality as before. A little adjustment to pull the plug out that one mm makes the headphones sound great. I have seen some Chinese audio gear that will actually come with a little non-conducting washer to put at the base of the tip to prevent this sort of thing."Tubes Died 10 Months In" I say died, but it was more like someone put a Karaoke filter in line when listening to music from Amazon Music Unlimited where the USB was the connection to the Douk P1. There were no vocals other than very faint and distant barely audible sounds of vocals. I checked if I had any filters in place and chose the digital output of the Realtek sound card in my PC to my stereo receiver and the vocals were there. When I bought the DAC/AMP I had purchased the matched pair of tubes at the same time. I went and found those and replaced the original tubes and magically the vocals were back. If I were Karaoke DJ this could have been a great feature, but alas I am not. Maybe I should sell those tubes and make some $. Interested? Just kidding sort of...I used this DAC/AMP as my primary DAC for about six months before buying a Topping DX3 Pro+. This Douk P1 is decent and provides Bluetooth, USB, and analog RCA inputs with only analog RCA and headphone (3.5mm) as outputs. The advertised rate for digital audio when connected via USB 24bit,192Kbs. Where it sits now is next to my primary Windows desktop connected via USB where my previous set up was with a MacBook Pro on USB. In both instances, the unit was set to the advertised bit and speed in the OS and Amazon Music reported the capabilities as those numbers and a particular track of Heart/Barracuda was played at that rate as verified by looking at the UltraHD link in the player.Of the features I consider positives are the volume and tone controls. These make it easy to tailor the sound to the type of music I am listening to and the particular headphones I am using. The switch to activate a blue or orange LED in the tube socket to give a hint a that color works, but the effect is minimal unless you are in a dark room. Perhaps that LED color switch could have been better leveraged as gain boost and decrease option, but that might be considered redundant with a volume knob. So, maybe a LPF or HPF option. The other switches are for input selection and tone control on/off. As far as sound quality goes, I like the sound it produces. When the tone control is enabled, I have the bass knob indicator at about 3 o'clock and the treble at max (I have old ears with high freq hearing loss) with some Sennheiser HD660S cans. Turning off the tone control and turning up the volume knob gives me almost identical sound qualities with some more punchy high mids as would be expected from those headphones.Overall, I like this DAC/AMP and it will be the DAC I use while working in my office while the Topping Dx3 Pro+ will be my primary easy chair listening station DAC paired with my Mac and Cambridge Audio DVD89 CD player.

I use this thing almost every day and am satisfied.

Overall, it's really great, but 3 things I wish were different.I wish the usb was usb-c and provided power. I bought a usb-c to usb-b cable so I can plug in my phone to avoid bluetooth audio quality issues. My phone battery drains while using that setup. I'm not sure yet, but I think after the phone battery gets lower than a certain point, audio over usb stops working to save the battery.Also, the rca analog input isn't really a passthrough and it goes through the pre-amp, which adds more distortion unnecessarily. So there should be a bypass switch or always bypass. I'm not interested in bass or treble or volume control.Also, if it had a phono MM input, I wouldn't need a separate piece of equipment for that.

I’ve only had this little DCA for about a week. I am impressed by the clean sound signals it sends from my latptop to my studio monitors - the Presonus E5 XT. I am using the entire setup with my midi keyboard. Decided to go for a nice DCA instead of an audio interface such as the Focusrite Scarlett as I am not planning to record with microphone, guitars, etc.As recommended in previous reviews, I also upgraded the two tubes to the Russian Voskhod 5654 6J1P-EV/6ZH1P-EV available on the B*A*Y. Disclaimer: I am not a professional audiophile so it’s hard for my ears to tell apart all the sound nuances. I also haven’t tested them at high volumes or played around much with the trebles and bass. Having said that, the Russian tubes are of smaller profile and continue to produce the nice warm sounds that came with the original tubes that I will now have as back-ups. I may update this as I gain more experience with the sounds.The Bluetooth function has worked flawlessly and the sound quality out of my speakers has been great. A feature that I found odd but interesting at the same time is that its Bluetooth will connect to two phones or devices at the same time. This will allow two people to DJ back and forth without having to ask the other person to disconnect first. I didn’t see this being mentioned before in previous reviews.I wish the headphones line-out were the bigger female 1/4” connector to be inline with professional brands of audio interfaces and equipment. It is the smaller 3.5mm (1/8”) which I had to buy an adaptor to use with my 1/4” professional headphones jack. But as long as you have a solid connection, there should not be any sound quality degradation. In the back there are two RCA line-out connectors to your L/R speakers. The connection will be inherently “unbalanced” which is actually desirable if you run speakers up to 10 ft. Longer than than and you run into “balanced” territory. Just for grins, I could not find any vendors on Amazon that would sell RCA balanced cables. Balanced cables all came with 1/4” jacks or XLR connectors. Again, a balanced connection is only needed for very long cable runs where you will expect some noise interference (cables basically start working as antennae picking up noise from other cables and electronic equipment) at the expense of some slight sound degradation usually in terms of volume. So I figure the vendor has this little device mainly contemplated as a desktop where the speakers will be placed at a short distance. It works for my purposes, but it may not work for everyone.So far I am very pleased with the quality build, the aesthetics (looks retro in a very nice way) and, most importantly, with its high quality sound signals. Obviously, your choice of speakers/studio monitors ultimately will dictate the sounds you get in your ears.