If you are trying to power 8ohm speakers you will be very disappointed as you only get 40wx2. If you have 4ohm speakers you double your wattage to 80wx2. Verify the ohms on your speakers before you purchase. at 4ohms it produces a very crisp clear sound.

This amplifier is really nice quality. It comes with a power supply and a set of 1/8" stereo plug to left/Right RCA plug leads that will allow you to connect a headphone output from a PC or other device to the amplifier, and a brief manual with specs and a simple wiring diagram.. The provided power supply is a 19.5V/3.33A ~65W unit with a typical 5mm/2.1mm barrel connector.The amplifier sounds really nice and seems quite neutral, refined and definitely lower in background noise than most other competing amplifiers I have used. It fits nicely under a monitor on my desk and doesn't take up much space. Highly recommended. Unlike another reviewer, I do not have any issues driving passive speakers to very good levels with this amplifier. The position of the volume control has nothing to do with overdriving the amplifier. If you have to turn it up high to hear anything, it just means the input signal is too low..The amplifier itself is quite small. It is smaller than my smartphone, but about an inch or so thick. The back has the power input (printed 19V- the manual states 15-19V) RCA inputs and screw terminals speaker outputs for 2 speakers. The front panel has a power switch that does not cause speaker thumps when turning it on and off, and a nice volume control. On the lower right corner of the unit is a 1/8" stereo input for connecting a phone or other device as an input to the front of the amplifier.I like the speaker connectors because they are screw terminals and they hold the speaker wires very tightly. Some of the competing amps come with small cheap banana/wire type jacks that don't seem to do a good job of holding either type of connector and the wires come loose over time.I have tried a number of small form factor amplifiers and they all suffer with some sort of issue. They are either noisy, or they have turn on thumps or they have speaker wire connections that loosen over time. This amp has none of those problems. I really like it.

My intention was to use this amp for powering passive speakers for audio editing on a PC but it is underpowered. It's a well built and very clean sounding amplifier but is underpowered to use for passive bookshelf speakers. I hooked it up to a pair of JBL two way with 6.5" woofers that are rated from 10 to 100 watts and this barely powered them. I had to turn up the volume control halfway to three quarters just to get some listenable sound from the speakers -- not good for the amp to be overdriven constantly like this. They claim that the amp is 40 watts output into 8 ohm speakers but I seriously doubt that figure based on the speakers I hooked up to it. I am initiating a return and plan to purchase a more powerful audio amplifier like the 300 watt AIYIMA TPA3255 that will put out 60 to 70 watts into 8 ohm speakers and double that if you use 4 ohm speakers. If you need a lower power amp then this has clean specs with something like .02% total harmonic distortion but the speakers need to be very very efficient with low power rating. I give it 3 stars because of the low distortion specs.