Bests & Worsts Reviews from Amazon

First off, Me I have 14 years experience working on military electronics, and 18 years personal experience working with, building, and repairing audio equipment... So we have a little 2.1 Amp, listed as a 2x40Watt and 1x68W... so ok I automatically assume that those are max peak numbers, normally peak is listed as 1.5 - 2 times the RMS output so I expect to get an inexpensive 2x20Watt 1x34w amp.... NOPE... THE SHORT: this is a Very poorly build and very misrepresented product... Real SPECS: 2 Channels @ 7 Watts RMS and 1 Channel @ 28 Watts RMS @ 10% THD 2 Channels @ 2 Watts RMS and 1 Channel @ 12 Watts RMS @ 1% THD Honestly don't waste your money. THE LONG: Testing Setup: I tested using 3 different power supply's : #1 : The stock 12V 3A (36W) it comes with. #2 : A switchable 12,15,16,18,19,20V 4.5A (90W) universal laptop supply. #3 : A 15V 40A (600W) Meanwell Switching power supply. Two different loads: #1: 2x 4ohm 50W Boston acoustic 4" drivers, and a pair of HiVi F10's (10" 100W driver) in parallel for a 4ohm load #2: 4ohm 3600W dummy loads. test equipment: ATTEN ADS 1062 60Mhz oscilloscope Fluke FM27 Digital multimeter Audio tool App on a android based phone (signal gen and basic RTA) using a Dayton iMM calibrated Mic. So I unpack the amp and check its Power supply... no problems, 56mv RMS of ripple, max I could pull out of it was 3.2A @ 11.6V, so it meets its specs... I hook it up and connect the 4" speakers. then i connect the source to it and run a 1KHz test tone at 320mV RMS into the RCA Jacks: Max output was 5.6V RMS, or 7.8Watts per channel... and there is a LOT of distortion compared to the input signal, and an odd pulsing fuzz on the o-scope... Hmmm next I test the sub output... using a 100Hz test tone this time, still 320mV input, at max I got 9.6V RMS or about 21.6Watt. Again there is a LOT of distortion and that pulsing Fuzz on the O-scope... next I use the 15V setting on the 90W laptop supply: 32mV RMS ripple on the PSU, and it will put out 5.8A... The Amp still maxes out at about 8W for the 2 main channels but I get 10.6V RMS or about 28W from the sub output now... Still have the distortion and the fuzz on the O-scope... finally I switch to the 4ohm dummy loads and the 600W Meanwell power supply. 15mV RMS ripple and WAY more amperage than this little amp could ever use... Still 8W per channel, and 28W for the sub...no change in distortion or that odd fuzz... so next I test the amp with no signal, that fuzz is still there independent of the volume controls, it looks somewhat like ringing noise discharging thru a capacitor... so I tear the amp down... the preamp and tone controls use a 4558D dual op amp, not Bad, but far from good. the main amplifiers are a TDA7266 and a TDA7256... the TDA7266 is a 7 W + 7 W dual bridge amplifier, you can look up its data sheet.... it's RATED at 7W @ 10% THD per channel or 2W @ 1% THD (100Hz to 15KHz)... The TDA7256 is a 30W Bridge Amplifier rated for 30W @ 10% THD or 12W @ 1% THD... next I look over the layout, and I notice that the entire power load is going thru a single 20AWG jumper wire... there is a set of holes for there to be a Pair of jumpers but only one was used... then I see on the Ground side it's the same way, only it's only 22AWG! there is No inductor on the main power line just a 2700uf 16V cap. and a 3A protection diode. And as others mentioned there was almost no heatsink compound on the main amplifier chips. AT this point I stopped testing, I had intended to test its output response curve, and see what was wrong with the "crossover" it includes. But really I have no use for a 7 watt amp... I have built Pre-amps that could put out that at less than 0.03% THD... let alone 10%... so really don't waste your money, for the cost of this amp you can go down to Walmart, K-mart, Biglots, or whatever and buy a 2.1 computer speaker set and strip the amp from it, and be better off...