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4 out of 5 stars
Lepai LP-2020A+ Tripath TA2020 Class-T Hi-Fi Audio Amplifier with Power Supply
Size Name: LP-2020AChange
Price:$26.75 + Free shipping with Amazon Prime
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223 of 258 people found the following review helpful
VINE VOICEon March 15, 2012
Size Name: LP-2020AVerified Purchase
This is a clean sounding amplifier with only the controls one really needs. So its great for my parents who don't have the frame of mind to fiddle with too many controls. However, be aware of power supply issues.

1) I bought two of these at different times from Amazon. Both did not ship with power supply - even though they claimed to include them. Amazon has not corrected the product description even after I told them about it.
2) The shipped power supplies were to be a 2 amp one and a 6 amp one in the second case.
3) If you run this amplifier from a 2 amp power supply - here is some news for you. The theoretical max watts your system can deliver would be 12X2 = 24 watts - However, since the amp is running around 80% efficiency - you can get approx 24X0.8 = 18 watts max from this amplifier (best case scenario) or around 9 watts per channel. The problem comes as you drive the amplifier harder. The power supply voltages will start dipping, and as it does so, the amplifier will distort. So your clean sounding amplifier, won't sound so clean after all once you drive it past 7 - 8 watts.
4) To really use this amplifier with low distortion at high volumes, you should use a switching powersupply that delivers 12 to 13.5 volts at 4 amperes. 6 amps is a bit of an overkill, but recommended if you will be using 4 ohm speakers.
5) You cannot use this amplifer with an un-regulated transformer type powersupply rated at 12 volt. Their no-load voltage can be anywhere from 15 - 20 volt and can even be dangerous if connected to this amp - since the supply capacitor is rated at 16 volt.
6) Don't forget the log relationship between perceived loudness and watts - a 100 watt amplifier is only double the loudness of a 10 watt amplifier. So this amplifer does fine to fill up a room with sound using reasonably high efficiency speakers (I am using Bose 301's). Just don't expect to pump your subwoofer with it!
7) There are two LED's inside. Not sure why only one of them lights up (in both the amplifiers I purchased).
8) Its tone control implementation can do with a bit of improvement.
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17 of 17 people found the following review helpful
on November 23, 2011
Size Name: LP-2020AVerified Purchase
This little amp is just amazing. If you're even remotely interested in audio, amps, etc, then this is a no-brainer: look at the price, realize that it's only $20, and just buy it.

For me, this replaced a $300 Sony receiver which had served me well for about 4 years, until its right channel suddenly died one day. (Actually, it's not quite dead, but it's permanently stuck at ~5% of the full volume coming out of the left channel.) And this little amp is somehow both louder and clearer than that 100-watt Sony receiver ever was (playing through the same speakers, a pair of Infinity RS3s, which have been going strong for about 10 years).

I'm a music lover with hundreds of CDs, but I wouldn't say I'm an audiophile; however, I have a friend who is, and he's been happily using one of these class-T amps for years.

The only real cons I see with this amp are:

1. Lack of remote control. I plan to eventually get a preamp with remote, so that will take care of it.

2. The obnoxious bright blue LED ring around the volume knob. Unlike many obnoxious LEDs on modern electronics, this one can't be fixed with a small square of electrical tape covering over it. I had to open the amp and desolder the two LEDs from the circuit board to remove them. And it was kind of a pain because they're positioned sort of halfway underneath the volume knob. So that took half an hour or so, but the amp's appearance is much improved by it. Note that the plastic ring around the volume knob is clear, not blue; it's the LEDs that are blue.

Regarding the included or not-included power supply: my amp was sold by Parts Express and fulfilled by Amazon, and it did NOT include a power supply. But I have plenty of 12v supplies lying around, so this wasn't a problem for me; indeed I'd rather not pay for another supply that I don't need. And it seems insane to me that people are complaining about having to spend an extra $10 for a power supply; Amazon sells several of them. (And for anyone who doesn't know: you just need to get one with a matching voltage [12v] and *at least* a matching amperage [so 2A or more].)

Finally, regarding the different variations of this amp: the one I ordered was "Lepai Tripath TA2020" (product ID/ASIN: B0049P6OTI). But the box it came in says "LP-2020" and lists the power requirement as "9-13.2V 4A". But then, the amp itself says "LP-2020A+" and "12V 2A". So apparently they aren't real careful with matching the variations to the boxes and the webpage, etc. (And my "LP-2020A+" *does* have the tone/direct button.)
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513 of 642 people found the following review helpful
Size Name: LP-2020AVerified Purchase
This is a sweet little stereo amp based on T-amp chip technology. It is clean and powerful for its size. It comes with a wall wart power supply, but could also be battery powered if one desired. There are input connections in stereo RCA jacks and a 1/8 inch (3.5mm) stereo plug for mp3 players, CD players, video players, etc.

There is an actual power switch instead of a pot-based switch as on similar models previously offered by Sonic. There are also Bass and Treble controls, which can be quite handy in tailoring the sound a bit to the speakers and space.

I am using these for small PA applications and for desktop computer sound. I have plans to create a small guitar amp setup as well. I have used 6 of these in my "day job" and was so impressed I started buying them for home.

I have driven spot monitors like Carvin PM5-Bs and even JBL 10 inch 3-way studio monitors with these and similar amps, and they work very well, especially for small areas. One of these and a pair of Carvin monitors make for some pretty great desktop computer sound. (Until your cubicle neighbors complain, anyway.)

I haven't done any actual power measurements, but they are claimed to put out 20-25 watts per channel into 4 ohms, and my ears agree that those figures are probably accurate. I have only run them at 8 ohms, and have been pleased with the sound. I currently use one of these and JBL 10 inch 3-way studio monitors to provide computer sound for a 42 person classroom, and the sound is pretty amazing for a $20 dollar amp.

If you are looking for a small power amp that is light weight, takes up very little space, and sounds really good, look no further. Give these a try, I think you'll be impressed, too.

Oh, Parts Express is also great to do business with.

UPDATE: August 2011

In the interest of clarifying the power output capability of this amp (which has caused some contention - see comments), I am re-producing the stats for the TA2020-20 chip from Lepai's own spec sheet, which is freely available on the web.

"The TA2020-020 is a 20W (4ohm) continuous average per channel Class-T Digital Audio Power Amplifier IC
using Tripath's proprietary Digital Power Processing (DPPTM) technology. Class-T amplifiers offer both the
audio fidelity of Class-AB and the power efficiency of Class-D amplifiers."

"Class-T architecture
Single Supply Operation
"Audiophile" Quality Sound
0.03% THD+N @ 10W 4ohm
0.1% THD+N @12W 4ohm
0.18% IHF-IM @ 1W 4ohm

High Power
25W @ 4ohm, 10% THD+N, VDD=14.6V
22W @ 4ohm, 10% THD+N, VDD=13.5V
13W @ 8ohm, 10% THD+N, VDD=13.5V

High Efficiency
88% @ 12W 8ohm
81% @ 20W 4ohm
Dynamic Range = 99dB
Mute and Sleep inputs
Turn-on & turn-off pop suppression
Over-current protection
Over-temperature protection
Bridged outputs
32-pin SSIP package"

"APPLICATIONS
DVD Players
Mini/Micro Component Systems
Computer / PC Multimedia
Cable Set-Top Products
Televisions
Battery Powered Systems"

The diagram with power to distortion curves is even more instructive, and I will try and add a jpeg of that so people can judge for themselves if Lepai is lying about the specs.

Are they fudging a bit calling this a 20 watt per channel amp? You could certainly make that case, given that they are quoting those specs at 4 ohms and 10 percent distortion, which is more distortion than most people would find acceptable in an audiophile application. Is Lepai pushing it a bit? Yes, but no more so than most consumer amp companies, or virtually ALL computer speaker makers, none of whom quote accurate specs for their systems.

I have been told by tech support for a well-known, widely sold PA amp manufacturer that they considerably over-spec their amps - their 120 watt amp can only be driven to 80 watts; if you go beyond that they WILL fail (which ours had done). Yet, they still sell the amp as a 120 watt amp and no one sues them. Lepai is not fudging anywhere near that badly, and they publish the actual specs for all to see. Carvin is the only company I have found to be truly honest about amp specs (although there may be others). Lepai at least gives one the specs so one can see how much they are fudging.

Are there applications where 10 percent distortion IS acceptable? Certainly. Some small PA and background ambient systems would be fine with that level. Obviously, listening to pristine recordings of orchestral music would NOT. A great deal depends on program material, speaker quality, and application. For most applications, 10 percent is not acceptable.

Again, I run these amps at 8 ohms through efficient speakers (Carvin PM-5B and JBL studio monitors), and find them to be very good performers FOR THE PRICE. I would not recommend running them into 4 ohms, unless you intend to keep the power level down.

At 8 ohms, per their device curves, you can hit 10 watts per channel and stay near or under 1 percent distortion - which is the definition of "High Fidelity" by international standards, and beyond which the normal human ear cannot discern any further lowering of distortion, according to some. At 4 ohms, you can get close to 18 watts per channel and still remain under 1 percent. Is it fudging to call an amp that produces 18 watts per channel at 1 percent distortion a "20 watt amp?" Not by much, and certainly not by the usual standards of most manufacturers. NOTE that with the stock power supply, 12 volts at 2 amps, you could not possibly get more than 12 watts per channel, if it were a perfect world (which it is not). A beefier supply would be required to get closer to those rated specs for the chip in this amp. Personally, I would call this a 10 watt amp, not 20. More and more vendors are adding the channel outputs together, rather than giving the per channel output, which has been standard practice in the stereo world.

Even so, I find these to be very useful little amps, and will continue to buy and use them as long as they are available. If you cannot afford the rather modest price to find out, then don't risk your money. If you want a good performing amp for the price of a few lattes, then go for it. I think you will be happy with these. If you are looking for an amp for your Home Entertainment system, I think you will want something with a lot more power. These are small amps for small jobs.

Also, if you have a power supply failure, which I did have with one of these amps, Parts Express has very good replacements for a very good price. Parts Express is a very good vendor, and I have bought from them for many years. I bought all 7 of the amps I have used from Parts Express.

Still highly recommended.
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243 of 306 people found the following review helpful
on April 25, 2011
Size Name: LP-2020A
Currently running Pandora via Netflix, through this box, into old Dalhquist speakers.
Sound is simply astonishing. No distortion, strong warm base, a little muddled in the middle (but hey, it cost less than $20 on Amazon), runs cool, very loud at 1/4 volume.
I'm a techie, having build many amps over the past 30 years, including tube amps (Dynaco 70).
- There are plenty of amps that cost 10x this, which don't come close in terms of sound quality.
This is my first review.
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97 of 123 people found the following review helpful
on February 7, 2011
Size Name: LP-2020AVerified Purchase
The outside quality is adequate. The sound is full and balanced with a wide range. I didn't expect that the lows could be so strong and deep from such a tiny closed aluminum box (still cool with running for a long time, say one hour from my impression) costing only about $25 with shipping and handling charges. It's a miracle! When the volume is up to 2/3, there is still no discernable distortion. The 3.5mm input jack is extremely convenient for you to connect almost every audio source.

The only weakness to date is that there is a noise (not big though) when I shut down the power, even if I turn down the volume to zero.

In a word, this product is almost perfect for its purpose, especially when you take its size and price into account. If you need a simple and compact stereo, buy it ASAP, since the price could go up soon, and since you'll be most likely impressed.
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46 of 57 people found the following review helpful
on December 28, 2011
Size Name: LP-2020AVerified Purchase
Sounded just fine but within minutes began to momentarily cut out with an audible click, then after about ten minutes it died completely.
Replaced it with a Pyle of the same rating (for more money), didn't have time to risk getting another defective one. Thankfully Amazon's
easy return policy makes such things relatively painless
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137 of 179 people found the following review helpful
on November 26, 2011
Size Name: LP-2020AVerified Purchase
For the first couple of weeks, I hated this amp. Connected to my Denon speakers, it has terrific sound, and seems well built, but it had this nasty buzzing sound that drove me up the wall whenever the amp was on but nothing was playing loud enough to drown out the buzz. If you read the reviews on this amp, many, many people complain that there is no power adapter included. Then, you will find some comments that they are including a Vonage power adapter with it now. You will also find some complaints about an annoying buzzing sound. Well, my friends, the buzzing noise comes from that Vonage power adapter. If you provide your own 12v power supply, it works great and has very clean sound. I thought about returning this unit, but I can't get anything comparable for even twice the price, and 12v adapters just aren't very expensive. In my case, I had one just sitting around, and was delighted with the result. The amp is a keeper, the Vonage power supply is a tosser.
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24 of 30 people found the following review helpful
on February 16, 2012
Size Name: LP-2020AVerified Purchase
I know this thing already has 189 reviews on it, but this is such an amazing little amp that I just have to make it 190. I just had a 300-watt rack-mount Carvin go out on me, and I was looking to replace it. I didn't want another rack-mount because I no longer have a rack and no longer need that kind of power -- I'm just driving a pair of Alesis Point Seven studio monitors. I went through at least 200 reviews on more than 30 different amps, and I reached several sad conclusions.

[1] Manufacturers flat-out lie about the power of their amps, generally citing peak power rather than the industry standard average (RMS) power. So you can order an amplifier advertised at, say, 150 watts per channel, and receive an amp that actually puts out 15-30 amps. Also, more and more companies just combine the channels to boost the power rating, so if the description doesn't say "xx watts per channel," the power is probably xx/2 per channel at best. This is very frustrating because you have to read the specs on every amp in order to identify the ones that might actually meet your needs.

[2] The failure rate on amplifiers is appallingly high. If you just read the reviews on Amazon (which reflect what I found on the other sites I used), inexpensive amps tend to have a bimodal distribution of ratings, with threes, fours and fives from people who could actually hear something from them, and a bunch of ones (Amazon -- there should be a *zero* rating) from people whose amps were DOA or failed before they took the time to write a review. The most common complaint is that one channel works intermittently, sometimes cutting out and then coming back in again, until it finally dies completely. There are a *lot* of reviews like this, particularly for the Pyle amplifiers that seem to sell so well on Amazon (WTTW: Read some audiophile reviews before buying these things).

[3] It is still possible to buy a decent amp from a quality manufacturer that is honestly rated, performs its intended function for more than a couple of months, and provides quality sound. But my sense is that you have to spend several hundred dollars to get past the junk threshold, and that's a lot of money for a desktop system or small studio. Now, don't yell at me -- I'm sure there are lots of good amps to be had for under $300. But given all the failures and complaints, it's pretty hard to identify which ones they might be.

Enter the Lepai Tripath Class-T Hi-Fi Mini Amplifier with Power Supply. That's a really big name for a very tiny unit -- it's about 4"x5" and under 2" high. The first couple of times I looked at it, I dismissed it as a toy, but eventually I came back to it given that I wasn't finding what I wanted for under $250. This thing drops a zero off the end of that price and it performs like a champ! It's only 15 amps, but it's a *true* 15 amps, and it is amazingly loud. It delivers clear sound through my Alesis monitors well past the danger point for ear damage. The sound isn't true audiophile quality, but it sounded great to my ears, and I tried it out on guitar, vocals, and a wide range of MIDI instruments. I couldn't do an AB test with my Carver amp because it was dead, but based on the sound the Lepai puts out, I don't detect any loss in quality. And I'm quite happy to be replace that 3-pound behemoth with this little gem.

Two other advantages of this unit are worth noting. First, it's based on solid state electronics -- I gather it's built around a single chip. I *think* (but do not know) that this could reduce the failure rate given that single chips tend to be much more robust than systems that rely on multiple chips, any one of which can cause the system to fail. And my reading of the other 189 reviews indicates a much lower rate of DOAs and early failures. But hey, even if I'm wrong, at $25, I can just keep a spare on hand.

Second, this thing runs on 12v, which is supplied by a wall wart. This means you can upgrade the quality of the sound by using a cleaner power supply if you want to (I read reviews by people who did and were happy with the improvement). It also means you can run it off of batteries if you like. This would be an advantage for people who want to go mobile with it, which I do. In fact, I plan to buy a second one and set up a very lightweight amp for my guitar -- one that I can stick in a backpack and play anywhere any time.

In short, it's a sweetheart. If you want a lot of sound for very little money, I don't think you can do better than this.
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9 of 10 people found the following review helpful
on August 11, 2012
Size Name: LP-2020AVerified Purchase
UPDATED REVIEW 2/8/13:

Both of the original Lepai amps that I bought are working perfectly. I decided to buy another for the living room, but instead of buying it from Parts Express, my original seller, I decided to buy directly from Amazon. BIG MISTAKE ! It arrived a day late (ONTRAC shipping SUCKS !) it came in a different amp box that didn't even match the item and to make things worst it did not come with a power supply. Then when I plugged it in with another power supply, it didn't even work !! I returned it instead and now waiting to get my money back.

==================================================================================================================

Ok let me just start out by saying that this little amp is powerful for its size weight and cost, but one suggestion...get a better power supply. This thing is LOUD!! Nothing wall shaking or anything of that sort, but for a patio or pool, it's more than enough.

Forget about the power supply / adapter it comes with, it's garbage! After turning it up too loud, the power supply can't take it, the blue light on the amp dims and the amp cuts off if turned up too loud. Now this isn't the amps fault, its the lack of power the supply pumps out. I bought a 12v 5amp power adapter for $9.99 that was meant for a computer monitor and it sounds so much louder and pumps out more watts. Now remember this amp does distort if turned up too loud, but that's expected with something that only cost twenty $20 dollars.

Problem solved, after the new power supply, no more cutting out, no more blue dimming light, everything is working perfectly!
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18 of 22 people found the following review helpful
on June 24, 2011
Size Name: LP-2020AVerified Purchase
Like many who have bought a HDTV I was disappointed with the sound level that the TV provided. Really it was to be expected just how does an ultra thin TV able to provide good sound from speakers that are as thin as the TV? Reading the many reviews on SoundBars and 2.1 sound systems there always seems to be negatives about them. The prices ranged from $98 to over $500 and not everybody seemed very happy. All I wanted was more volume and a quality sound. Why couldn't I build my own system that could achieve those same results? So that's what I attempted to do. I read the reviews on the amplifier, Lepai Tripath TA2020 Class-T Hi-Fi Audio Amplifier, and the reviews on the affordable speakers, Dayton Audio B652 6-1/2 2-Way Bookshelf Speaker Pair, here on Amazon. I put the system together here for just $65. Wow, I got the results I wanted and we are happy. Now, it's not surround sound, nor does it have a real stereo effect. The quality sound level is all we wanted. At half the volume that this system is capable of, it blows us away. We control the volume from the TV using the option within the TV itself. So if you are looking for the same results then this home brew system isn't going to break your bank account. Good luck in your search.
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