2 Channel Bluetooth Amp: HiFi Stereo Amplifier | 300W×2 TPA3255 | Class D PFFB | Bass Treble Control | Headphone Out for Home Theater, Bookshelf Speakers (32V PSU)

I bought my A5 pro in July. Used it for a while with the stock op amps and then added opa2134. Bought them from Mouser, wanted real TI product. Sounded good enjoyed it -everything's fine. Then I changed to two SX52b -Listening to a live marillion album hearing details I never heard before, vocals are more clear the entire sound is improved. Definitely better bass. I am using the 48 volt 10 amp power supply and some Elac speakers. What a great amplifier and so affordable. ****Update. 10/18/2025 - Some music started to have a shrill sound in the upper register, the treble was off. Investigated with Gemini my AI and determined the sx52b was not a good fit for a amplifier. Suggestion was to put it in my tube preamp or equalizer as the sx52b adds a definite sound of its own. Gemini had reasons related to electrical specifications and impedance I didn't understand but that was which was suggested. Research the newest TI op amps for music determined that the 1656 would be a great choice but it's not available in a dip 8 socket. I purchased the OPA 1656 mounted into dip 8 socket from Cimarron Technology, Inc (Idaho ). Great company to do business with. Installed the two opa1656 which are known for their clarity, fantastic specifications - but they are neutral and don't add coloration. Tested this all out yesterday and I was shocked. Much better stereo separation than I had before, much better bass. If someone tells you changing op amps doesn't affect the sound I can't explain what's wrong with their ears. :-)

I am using this amplifier for my LG television. I am plugged into the headphone output. Volume control is by the tv. The amplifiers volume control is what I would call 3/4 open. I have tried several amplifiers including the famous A07 by aiyima. The Fosi bt20a. Aiyima T4 amp. They all sounded pretty good. A07 I would have ranked second for how it sounded. But I needed Bluetooth without adding equipment. I use Bluetooth as a radio when I am not watching television. Bluetooth works without a hitch, no issues there. Connects to my tablet or phone with ease. Now the amplifier for using for the television is great. Running through JBL Northridge e-20 speakers. They match up pretty well. Sound quality is very good. The main reason I chose the Duck Audio A5 pro is 1,uses the 3255 power chip 2, like is said I needed Bluetooth. 3, it also uses the PFFB technology. Now with such a good sounding amplifier why only four stars. Because it does run ,to me ,very hot. I never had a D type amplifier run so hot. Just makes you wonder how long it will last. Oh well I will find out.

A small wonder in the making ,and can potentially be even better if you change the "op-amps". I am in the process of listening to the standard amps, but the sound is so good you don't really have to change anything. Maybe could be a remote, but if you are bit creative you can remote control the power supply and set sound controls at a medium setting. Then stream Spotify to the amp and control the rest from your mobile. A fun and quite impressive sounding amp.

this little thing packs a whomp. took my computer listening sessions to a whole new level.

Works well definitely not the wattage listed and do not like the fact you have to shut it off after each use ..or you'll have to unplug it for a time to reset itself????? Sounds is good, nice looking unit

It works as advertised and does a decent job as an loudspeaker amp. Bluetooth connectivity worked just fine, even without the antenna in place it streamed music from my phone with zero issues as long as I was within 10 ft. of the amp. The tone controls also were properly implemented. Controls were all top-notch, with nice damping to the tone/volume controls, and I appreciated the solid feeling front panel Off/RCA/BT switch. Unlike some competitors that will flip the BT receiver on whenever in range of a transmitter it remembers, Douk did the right thing and let the user decide which input is to be used. There is one hang-up I have with this amp's design: as others have stated, at idle this thing gets warm. It's the inductors that have the most heat generated at idle, not the TI switcher chip. This has been a gripe about more than this amp when implementing the PFFB feature. I'm guessing this is seen in many designs since they all use the same reference design in the TPA3255 datasheet. What's odd though is when the amp is under light load (i.e, playing music at say under 5W), the entire amp cools down. This is counter to my 37 years designing PWM buck regulator chips, the basic technology these class-D amps are based on. These class-D amp designs are definitely different than the typical high-power switching regulators I worked on for decades (and are ice cold at no-load conditions). What's funny (to an engineer like me) is that class-D amps are supposed to be power efficient compared to class AB amps but at light to no load it sure doesn't seem like it. Switchers are definitely vastly more efficient as power supplies compared to a linear supply but not-so-much with a class-D amp vs. a class AB amp in certain cases. Luckily Douk Audio put that glass top in this amp's case. I took advantage of the hole to install some small aluminum heat sinks on the inductors. It helped reduce how hot the inductors got at no-load, but still, it's baffling why this thing gets so warm at no- load when current in the inductors should be zero.

I bought this to have something to listen to while my expensive amp was being serviced and it is amazingly good for $100. Definitely worth keeping one around as a spare or even as a main amp for a small modestly-priced system. The one thing to note is that the binding posts are tiny and will only accept banana plugs with slim shells. My Audience cables fit without a problem, if that gives you a starting point.