SA 400.4 4-Channel Digital Car Audio Amplifier, 400W RMS 2 Ohms Stable, Compact Class D Multi-Channel Amp with Crossover & MOSFET Power Supply, Full-Range Sound Quality

NOT TOO BAD, tiny but decent sound, would recomend

Running my 2 skar audio 6.5 and 2 3 way 6x9 for 3 months now, love it. good audio quality. Honestly when I first got it I didn’t notice the little things to adjust the audio so it used to cut out when I turned it up too much but it’s too much for my speakers I have it like half way up and it’s loud would recommend

It's actually holding up more than a year later. Pumps my Jbl door speakers great. 1 minor problem is it gets hot pretty quick due to size.

Better then expected

The one I received died as soon as I started to adjust the gains. Sent it back.

Muy buena

I love this little thing. I am running 2-8 inch tower speakers and 10" sub on my sxs. Really loud and great bass

TL;DR: The internals are limiting the capability of this amp from becoming a 5/5 product.Pros: Affordable, Small Build, Simple Set-up, Good Power, Good looks.Can't find a cheaper amp than this one that is also in this small of a package. Drives my 6x9 pair and 6.5 components really well. Can't say the same for tweeters.Cons: Hiss on Tweeters (or any high sensitivity drivers), A shared "ground" between two channels.I was so impressed by them driving those woofers that I bought 3 more before I tested this on my tweeters and midrange coaxials. Thank the heavens for cancellations because I dreaded to hear that hissing sound coming from my tweeters.I have a DSP that can output more than the 4v output my Head Unit delivers on the RCAs so it's not a noise floor issue. I unplugged the RCAs and the hiss was still present. From what I have learned, this amp does not have a good filter to come along with it meaning it will produce high frequency noise regardless of how much voltage you pump through your RCA.Granted, the noise was low enough that you could probably drown it out if you haven't done any acoustic treatment to your vehicle and are always traveling through highways. If you are younger than me (31), it would probably be more apparent to you but for me, the noise is evident enough for me skip this amp and give it a 3/5. If you are older, you probably wouldn't even notice the noise and if that is the case, enjoy this powerhouse!