Review on 🔊 Yeeco HiFi 2.1 Channel Amplifier Board - 80W+80W+100W Stereo Audio Amplifier with Acrylic Case & Adjustment Knob by Shane Sanchez

That's a good value for an amplifier with stereo and separate subwoofer output. I'm glad I bought it and would recommend it to anyone who isn't an audiophile. It can be very noisy, although I have no way of measuring the true RMS value of the output. Make sure the speakers you use are rated for the power output. This worked especially for me as I had an unpowered "spare" subwoofer lying around. In contrast to some other amplifiers, it has a good housing. It has cooling vents, which it probably doesn't need, but still nice. Not so good if it's in a spill-prone environment. There are a few other things I liked. It is rotated, not glued. It uses mounting bolts with nuts instead of bolts driven into (thin) plastic that tends to peel off. And to top it off, the nuts and bolts are stainless steel. Small "legs" are built into the body. Because the case is not glued, the circuit board can be removed from the case when the case is not needed. Audiophiles: The amplifier is not for audiophiles. There is some hissing. Luckily I'm not an audiophile and for the price it sounds ok to me. Techies: This is a "switchable" amplifier. That's why it can have "up to 90% efficiency", doesn't get very hot, and has these huge toroidal coils and huge capacitors. Search for "switching power supply" for more information. This may also cause some noise. The soldering looks normal - there are no traces of rosin. There seems to be at least a ground layer, if not a power layer, but I can't be absolutely sure, at least the light doesn't go through the PCB, but it could also be a dark soldermask. All the parts are on top of the board, which is another reason there's probably a ground plane. Volume control: The master volume controls both the subwoofer output (bass) and the stereo output. The bass volume only controls the subwoofer output. I didn't get it at first, but the stereo volume controls the left and right stereo output. Yes, this is probably obvious to most, but I was wondering if it was a balance control. After all, the stereo output can be controlled by a combination of the volume of the main and bass signals. Most receivers don't have a stereo volume control, just a master volume control, and formerly before EQs, balance, treble and bass. The volume controls don't feel cheap when turned. Power connector: inner diameter 2.1mm, outer diameter 5.2mm. Minus: volume controls are not marked on the case. Added a label on the front. Minus: The hole in the case for the 3.5mm audio input is not enough. You need a small plug. They're certainly available, but if you don't have them, you need to get them before you can try them. Since the housing can be dismantled, the hole can of course be reamed larger. Cons: No access door for 3-pin audio input. But I think most who will use it will not use the case. The wire can probably be routed through the cooling slots, but I don't think the slot is wide enough to fit through the mating connector.