Question 1

Is this device intended for cars?  I'm confused by the cabinet configuration...

Accepted Answer

As a life-long electronics technician and audio amp audiophile from back in the day, I can tell you that since the device is rated at 12 volts, it is indeed compatible for automobile applications.  While not necessarily designed or meant for car audio, it will work. If you apply 12V to it as a power source, it will function properly.

However, there are a few things to consider:

1.  The power output (as you can prove to yourself by examining the pictures and actual specs of the device) is about 30 watts of total output power.  (15 watts per channel times two channels - left and right.)  This is evidenced by the power specs.  The amplifiers require 12V at 3A (which equals 12V*3A= 36W).  These are class D amplifiers which simply means that they are very efficient in their power consumption. These class D amplifiers are typically 85% efficient, which means that they will give you 85% of the power out that they consume.

2. Since the power supply (adapter) that powers these amps can provide 12*3=36 Watts of power, your audio output power is then 85% of 36 Watts = 30.6 Watts of output power to your speakers.  Again, this IS coming from a 12V supply.

3. As to the reviewers that claim that these amplifiers run hot, I again will refer to the math.  Due to the nature of how class D amps work, they don't get very hot. Consider that these class D amps are usually 85% efficient.  Since the total supply of input power is 12V * 3A = 36W of power, then that means that the amplifier is only consuming 36W * 15% = about 5 Watts of power at full loudness.  Five watts of power does not create very much heat at all. (About the same amount of heat that a little night light produces.)

4. While you can certainly install these lower power class D amps in you car once you route 12V to them, and they will perform well without overheating, remember that you're going to have to mount them somewhere such that they are in arms reach so that the power switch and tone controls are accessible.  Also the inputs to these amplifiers are RCA jacks which are very susceptible to the electrical interference that are typical in automobiles.

Bottom line: For the price, I love the sound and power output from these amps (I have two of them from Amazon that I use for computer audio and they get nice and loud and have good bass and treble).  However, keep in mind that the amps are typically sold either without strong power adapters, or are sold with no adapters at all.

Remember the power calculations that input Voltage times Current times the amplifier efficiency = the power output to the speakers.  I wouldn't put them in my car (since there are many better installation options available), but for computer or TV speakers/gaming, these amps get good and loud and are impressive, IMO.

Question 2

Using this am to power 2 external speakers. ok to keep the power on even when the tv is not?

Accepted Answer

Yes, it would be fine to leave it on.  The power draw would be almost negligible.  I have older versions of this amp (with the Tripath chip vs TI), and have had one going 24/7 for the past couple years in my kitchen.

Question 3

Is this 2 x 10watts or 2x 20?

Accepted Answer

Power supply specification is  12 V , 3A.   12V x 3A = 36 Watts.  So you are not going to get 20 watts per channel (40 total) even if the amp was 100% efficient, which it isn't.

Question 4

Will this amp work with the polk audio psw505?

Accepted Answer

Yes it will work with the psw505. I have mine running through a Sony SAS9 10" powered sub to my Sony 6 1/2" bookshelf speakers and it sounds awesome. You will need to connect the amp speaker wires to your polk sub 'speaker in' inputs and then wire the 'speaker out' to the speakers you are using.

Voltage	24 Volts
Manufacturer	Lepai
Mounting Type	Surface Mount
Brand	Lepai
Number of Channels	2
Package Type	box
Specification Met	CSA, CE, WEEE
Material	Tube, Metal
UPC	848864036892
Model number	LP-2020TI
Item Weight	431 g
Package Dimensions	25.4 x 14.2 x 5.59 cm; 430.91 g
Item model number	LP-2020TI
Output Wattage	20 Watts
Power Source	corded electric
Are batteries included?	No

Lepai Texas Instruments TPA3118 Hi-Fi Stereo Audio Mini Amplifier with Power Supply

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