Lepai LP-168HA Mini Amp Tested and Reviewed

Lepai LP-168HA "Super Bass" 2.1 Mini Power Amplifier

The Chinese mini amp invasion continues! This time we will show off the Lepai LP-168HA, a 2.1 channel mini amp. It is called a 2.1 amp, because it offers 2 stereo channels as well as a single "bass" channel. Sounds very promising at the rated 40x2, plus 68x1 power output. Now, as we've seen before, the manufacturer's ratings for these amps means nothing...Actual RMS output means everything!

The Lepai LP-168HA offers 3 inputs, all in parallel (non switchable). On the front, there is a 3.5mm stereo input jack, while the back offers left and right RCA input jacks as well as a USB port. The USB port will play back MP3 files on a compatible thumb drive, MP3 player, cell phone, etc. This feature wasn't tested other than for charging and it failed on 2 out of 3 devices tested. The 1st generation iPod Nano was the only device accepting a charge from the LP-168HA...neither the iPhone 3G nor the iPhone 4 would receive charge from the USB port.

Lepai LP-168HA's Rear Connections

The LP-168HA also offers a separate volume (and TINY knob) for the bass channel as well as the stereo channels. Unlike most amps offering a bass channel, there is no "master" volume controlling all outputs. You must adjust the bass channel and stereo channels independently. What a horrible design! Furthermore, the bass channel reaches full power at just a slight turn of the bass volume adjustment. There is no input gain control for the channels, just the volume knobs.

Speaking of input gain, there is a VERY important note here...I was unable to drive the front channels to clipping with an iPod Nano 1st gen or iPhone 4. It appears the LP-168HA wants an input of around 2-3V to reach max volume, and most portable devices don't have enough juice! I had to use my Yamaha home theater receiver with approx. 3V pre-outs to drive the LP-168HA to it's maximum volume. I didn't mention this in the video review, but feel it is a BIG deal.

Another area of interest is the crossover for the bass channel. I just verified my tests in the video using a 2nd example of this LP-168HA and both exhibit the same issue. The bass channel's crossover is cutting out some of the highs, but not fully until 2kHz or higher. I tested using a 1kHz test tone and was still able to hear it quite clear, even setting the crossover at 50Hz! Needless to say, you'll want to add a passive choke to keep your "subwoofer" from getting frequencies too high. Speaking of this, I'm not sure which "subwoofer" you'd use with this amp, but it better be a small and efficient one!

Lepai LP-168HA Controls

Watch as I verify RMS power output using the Velleman HPS50 and SMD DD-1 Distortion Detector. How close can we get to the manufacturers claim of 40x2 and 68x1? Well, you're gonna have to watch and see....

If you haven't seen the intro article to the "Chinese Mini Amp Invasion" check it out now. Also, I've made a video playlist of all the mini amps I've tested, see it HERE.

Make sure to Subscribe to my YouTube Channel to stay updated of my latest videos. You can also follow me on Twitter @oldschoolstereo.

See the Lepai LP-168HA in HD on YouTube

or embedded below:

SMD's DD-1 - New School Tool for Old School Amp Testing

SMD's DD-1 "Distortion Detector" vs. Velleman HPS50 Oscilloscope

Many of you who follow my blog and videos, know I've had a Velleman HPS50 oscilloscope for a while now and keep adding components to enhance the capabilities of my test bench. My primary focus now is testing amplifiers for maximum continuous RMS wattage output. We all know most of the ratings we see on amps today are not RMS, but MAX output. This is a marketing ploy, not useful at all in determining the actual output of an amplifier. I'll soon get one of these amps on the bench and show you actual RMS wattage output vs. the value claimed on the amp. You may be amazed and not laugh so much at the old school amps and their low wattage ratings...

I recently decided to pick up a SMD DD-1 "Distortion Detector". This device was developed by the brains at D'Amore Engineering in conjunction with the KING of car audio on the Internet, Steve Meade (www.stevemeadedesigns.com). Steve Meade (meade916 on YouTube) is famous for his 30,000 watt custom Chevy Tahoe and has several hundred videos. Steve is also the largest car audio channel on Youtube with over 100,000 subscribers and over 100 MILLION video views. Impressive to say the least, but this DD-1 is not hype, it is a truly powerful and affordable tool for everyone from electronics enthusiasts to car audio shop installers and many in between.

So, what's the deal with this DD-1 and why might you want one? The SMD DD-1 is marketed as an amplifier gain matching tool. Matching your car audio head unit and amplifier has been a black art for many years. Without an oscilloscope and test tone, setting gains was really just a guess for most folks. The DD-1 costs only a fraction of most oscilloscopes and offers simplicity in setting/matching gains for your car audio equipment.

Here's what's included in the package:

• The Distortion Detector (DD-1)
• Protective silicon rubber boot
• Calibrated Test Tone CD
• Harness
• Printed owner's manual

According to the manual, the DD-1 has the following specs:

• The DD-1's circuitry is 100% analog
• Distortion Detection trigger level > 1.0% Harmonic Distortion
• Guaranteed operating range of input signal is 1.2Vrms - 125Vrms (15,000 Watts at 1 ohm) Autoranging
• Signal Present LED trigger voltage 750mVrms
• Low Battery LED trigger battery voltage < 5.6Vdc
• Auto shut-off timer 8-10 minutes after on button is pressed

Now, I must be honest. The unit's ability to match gains is a great feature, but I've had this ability with my Velleman HPS50 portable o'scope for a while. A recent video on Steve's channel about the upcoming AD-1 "amp dyno" got the wheels spinning in my old school head. This DD-1 can be used for more than just matching gains...it can be used to assist in amplifier output testing! This feature in a sub $200 device is unheard of. A bench version of a THD analyzer can cost MANY thousands of dollars. I've been watching eBay for a year or more hoping to find a deal on one of these THD analyzers so I could verify distortion during my amplifier tests. After seeing the AD-1 demo, I was convinced to buy the DD-1 to use as a tool in my RMS output tests.

The DD-1 has proved to be an invaluable tool and will ensure accuracy in my amplifier tests. I have MANY old school amps I plan on testing in the upcoming months. The DD-1 will ensure < 1% distortion in my results which is great. As I mentioned above, not only do many manufacturers rate amps by "Max" output, they also sometimes use distortion numbers up to 10% for their ratings. I think it's important to keep the distortion less than 1%, which should be inaudible for most people.

I have done some initial tests with the DD-1 and have been impressed with it's ease of use and ability to detect low levels of distortion. See some videos below and be sure to subscribe to my YouTube channel to stay updated with the latest amplifier and car audio tests and demos.

Buy the DD-1 Direct at wccaraudio.com

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