Lepy LP-2020A

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For these tests, I'm trying to approximate the Audio Science Review tests in the hope that these results will be approximately comparable and useful to determine how items tested here compare to items tested there.  The shot above has most of the same info contained in the ASR "Dashboard"  This test is run at 5W into 4 ohms.  I used my variable power supply at 13.5 V (same voltage as tested in ASR).  My Lepy came from the Parts Express tent sale and did not have an included power supply.


Manufacturer's specs per Amazon (where you can still buy one for about $30 with a 13.5V power supply included)

Specifications:

- Brand: Lepy

- Input power:DC10-14.4V

- Output power:20wx2 RMS

- Weight: 360g

- Load impedance:4-8Ω

- Frequency response:20Hz-20Khz

- Total harmonic distortion:＜0.4% - SNR:>80db 

Gain:  ASR reported about 19 dB and pretty even in both channels.  My sample measured at 22 dB (right channel) and 21.5 dB (left channel)

THD+N%:  There was a lot of variation between channels in my sample:  0.18% in one channel, and 0.29% in the other.  The ASR sample measured better at 0.07% and 0.12%

SINAD:  This should equate to the inverse of my THD+N reading in dB, which was about 50 dB or 55 dB depending on channel.  The ASR sample was better at 58 dB and 63 dB.

Clearly my measurements were worse than ASR's, but at least in the ballpark.  Some of that might be attributable to the fact that my sample seemed to have higher gain, which often leads to more distortion.  We clearly aren't dealing with aerospace and defense level configuration management in a $25 amp.

Time to check out the frequency response.

My example of the Lepy was clearly optimized for 8 ohms and has pretty respectable response for a low cost amp.  There is no high frequency ringing and the response is down about 2 dB at 20 Hz and 1 dB at 20 kHz.  4 ohms is a different story at high frequencies, down about 5-6 dB at 20 kHz, which will definitely be audible.  It should be noted that there is about 1/2 dB of channel imbalance, which shouldn't be surprising given how different the two channels looked on the dashboard.  Interestingly, the ASR sample has slight ringing at 8 ohms and less rolloff into 4 ohms - a different filter choice.

Next up is the distortion vs. power to see how much output the Lepy can deliver.  

 Now, this is a mess, but it actually looks like the ASR measurements.  The two channels have different distortion profiles from each other.  The amp puts out about 10W at 4 ohms and 7W at 8 ohms.  ASR reported 10W at 4 ohms and 8W at 8 ohms.  Distortion isn't.... good, but I've seen worse.

All of these tests were run at 1 kHz.  Let's see what happens at other frequencies.

We generally see higher distortion at higher frequencies, which isn't uncommon for a budget class D amp.  What really stands out is how much the shapes of the curves differ.  Nothing crosses 1% distortion until about 4W at 5 kHz and above, which is reasonably acceptable for this price class.

To summarize my thoughts, the Lepy LP-2020A a low budget amp and it does act as such, but it really isn't too bad for what it is.  It mostly meets its specs.  The frequency response is much better into 8 ohm loads, so that seems to be the preferred application (if you have a sample like mine).  Clearly the only way this could be a 20W amp is if 10% distortion is allowed or you can combine the power of both channels...  Up to about 7 watts per channel into 8 ohms, the Lepy performed respectably.