Wednesday, November 30, 2011

500 Watts in Your Pocket? Kinter MA-150 Mini Amp

Kinter MA-150 vs. CD: Size Comparison

The promise of 500 Watts in a palm-sized amplifier is appealing to many people. The Kinter MA-150 is another contender in my Chinese Mini Amp Invasion shootout and is the smallest amp in the bunch. Although technology such as "Boosted Rail" has enabled Rockford Fosgate to make the PBR300x1 just slightly larger, it "only" promises 300 Watts of power at 1 ohm. Not to mention, the PBR300x1 costs around 10x as much as the Kinter MA-150...

I picked up the Kinter MA-150 from an eBay seller for around $15 US shipped from China. Now, logic will tell us we shouldn't expect much from an amp only costing a few dollars, right? Yes, this is a rational thought. "You get what you pay for" comes to mind. So, what does the $15 get you? Continue reading...

The Kinter MA-150 has a slightly different design than the other amps in this shootout as it requires molex-style plugs for the speakers and power. The other amps in this comparison have spring-loaded speaker terminals and a 5.5mm x 2.1mm center positive power plug.

Kinter MA-150 Speaker Output and Power Inputs

The opposite side of the MA-150 has a USB port for charging external devices, RCA L/R jacks, Volume knob and crossover switch. See picture below:

Kinter MA-150's USB, RCA, X-over and Volume adjustments

For more details on the technical specifications, please see the Chinese Mini Amp Invasion article for a spreadsheet comparing each amplifier in the shootout.

The Kinter MA-150 is heavily marketed on eBay as a motorcycle or scooter amplifier. Obviously, the main reason is the small size, low power consumption and "rated" high-power output. Now, logic and science will tell us, based on the MA-150's 12v 0.5A power requirement, you can use the equation Watts = Volts x Amps to get 12 x 0.5 = 6. Taking into account 100% efficiency, the amp should put out 6 watts, based on the power going in. Well, unfortunately, the amp is NOT 100% efficient, so even the 6 watts may be a stretch.

Power ratings vs. actual output aside, I decided to run the sound quality test first. I tested several tracks, including one of my favorite "Chelsea's Day" by Sam Cardon. It was readily appearant to me the MA-150 didn't have the power, clarity or dynamics of the Lepai LP-2020A+ . My reference speakers, the Athena Point 5 MKII bookshelf speakers are extremely transparent and it was obvious the MA-150 was struggling to push them to room-filling level. Again, based on the output I was expecting, this wasn't a surprise to me. After a few minutes demoing my reference tracks, I decided to put the MA-150 on the test bench and get some actual numbers.

Results? Not impressive and not even close to the 500 Watt rating. Using a 12V 35Ah Sealed Lead-Acid battery showing 13.0V of charge, I was able to obtain:

Output Test Results:

  • 4.56V RMS of Unloaded Output at the speaker terminals
  • 2.1 Watts RMS / channel at 8 ohms
  • 3.4 Watts RMS / channel at 4 ohms
  • 5.3 Watts RMS / channel at 2 ohms
  • 15.6 Watts MAX / channel at 2 ohms

(tests above were conducted using a 1kHz 0dB Sine Wave Test Tone from the SMD DD-1 test disk and output was verified by the DD-1, which detects distortion at 1%. The resistive loads of 8, 4 and 2 were conducted with BOTH channels loaded)

Stay tuned for more tests of these mini amps and see which one (if any) you should buy. Check out my video review of the Kinter MA-150 below. Make sure to Subscribe to my YouTube Channel to stay updated of my latest videos. You can also follow me on Twitter @oldschoolstereo.

See my video review / bench test of the Kinter MA-150 and decide for yourself if this is the amp for you...


Saturday, November 26, 2011

Chinese Mini Amp Invasion! Kinter, Lepai and More

Mini Amps Galore! 3 Models from Kinter, 3 from Lepai and 1 from TeLi

If you spend anytime on eBay looking at car audio amplifiers, then you've surely come across some of the amps I'm going to talk about here. Lepai and Kinter are just a few of the brands you'll see quite often. Some of these mini amps are small enough to fit in your pocket and promise 500 to 700W of power. So why spend several hundred dollars on a fancy name brand amplifier when you can pick up most of these for under $20 US shipped? In the near future, I'll test each amp for RMS Watt output and with some reference speakers and we may soon see why.

After receiving and testing my first mini amp, the Lepai LP-2020A+, I decided it may be interesting to pick up a few more of these mini amps and have a shootout! Here are the models I've obtained thus far:

Lepai Amps:

  • LP-2020A+ - my first mini amp, rated at 550W MAX (20W RMS) output. Tripath design, TA-2020, 2-channel, RCA/3.5mm input, bass/treble/bypass, large volume knob w/ blue LED backlight. 4-8 ohm compatible, 9-13.2V 4A power requirement (per box, amp says 12V 2A?). S/N ratio >80dB
  • LP-V3 - "This amp is use BOSE power IC" (my favorite amp quote). Rated at 700W MAX (25W RMS) output, identical in size to the LP-2020A+ (so why the 700W rating?). 2 channel, RCA/3.5mm input, bass/treble/bypass, large volume knob w/ blue LED backlight. 2-8 ohm compatible, 9-14.4V 5A power requirement (per box, amp says 12V 2A also). S/N ratio >80dB
  • LP-168HA - 2.1 (3 channel) design with ratings of 40x2 and 68x1 watts. Has separate volume for bass, built-in x-over, bass/treble/volume (all same size). RCA/3.5mm inputs, USB port, spring-loaded speaker terminals for Front L/R and Sub. 14.4v 5A power requirement.
Kinter Amps:
  • MA-150 - the smallest amp in the group, rated at 500W MAX. BTL desigh, filter for L/Off/H (x-over?), RCA L/R inputs, speaker/power connections by molex-style plug w/ attached wires. 12v 0.5A power requirement
  • MA-170 - Similar design to the Lepai LP-2020A+, but smaller. BTL design, 2-channel. Large volume knob, bass/treble adjustments, sprint-loaded speaker terminals, RCA L/R inputs. 9-14.4V DC power requirement, no Amperage specified. Rated at 100W PMPO or 4W x2 RMS, S/N ratio >70dB
  • MA-200 - largest amp in the group. 4-channel design using 2x TDA7377 IC's, rated at 41W x4 channels RMS at 1kHz. Has equal size knobs for treble/bass/volume. Includes display for function display; AUX or FM. Includes input for USB and SD/MMC card. 12V 5A power requirement.
TeLi Amp:
  • A6 - identical in size to the Kinter MA-170. 2 channel, BTL design, RCA/3.5mm inputs, bass/treble range +/- 15dB. 8-15V DC power requirement (no amperage mentioned)

See the latest Spreadsheet below with specs comparison or download it if you prefer:

Stay tuned for upcoming tests of each mini amp and we'll see which one (if any) you should buy. Check out the video overview of each amp below. Make sure to Subscribe to my YouTube Channel to stay updated of my latest videos. You can also follow me on Twitter @oldschoolstereo.



Big 'Ol Stack of Mini Amps!

Kinter MA-150 in Orion HCCA Red

Friday, November 18, 2011

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 ( 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 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




Friday, November 11, 2011

Can The Orion Take The Punch?

Rockford Fosgate Punch 45HD and Orion 222 SX

The Rockford Fosgate Punch 45HD and Orion 222 today's terms would be called "tweeter amps". Go back 20 years to 1991 and people were using these amps not only to power subwoofers, but in some cases entire systems! Since both amps were rated at 45 watts or less at 4 ohms (both channels), people either had really efficient speakers or didn't require high volumes, right?

Well, many people were told and believe the old school amps are always "very" or "highly" underrated. Read on to find out if this is the case with either or both of these mini powerhouses.

First up, the Orion 222 SX appears to have a heat sink surface area advantage at 8.5 x 8.5 x 2.25 inches. It carried an MSRP of $329 US back in 1991 (reference - Car Stereo Review, July/August 1991) and included the following specifications from Orion:

222 SX Ratings at 12 VDC (both channels driven):

4 ohms stereo - 22 watts RMS
2 ohms stereo - 44 watts RMS
4 ohms mono - 88 watts RMS
(not rated to handle 1 ohm stereo or 2 ohm mono loads)

More Specifications:

  • Requires external 15A Fuse, 20A provided by Orion (according to the manual)
  • Stereo, Mono or Mixed-Mono operation
  • Left and Right Peak Power LED's
  • 0.005% THD at rated power
  • Damping Factor - Greater than 500

On one side of the 222 SX are the power/ground wires (10 gauge), plus the 9-pin molex connector for speaker and turn on connections (See my Youtube Video on how to make these yourself!). The opposite end of the amp has input connections from both RCA and DIN connections. The DIN connection supports Orion EQ's and crossovers and provides phantom power for these devices as well. There are also two buttons, one for "EQ", providing a +15dB boost at 40Hz, -4dB at 200Hz and +6dB at 10kHz, in addition to a "Mono" button for bridging the amplifier. The 222 SX also has Peak/Power LED's and a single input gain control. See the connections below:

Orion 222 SX input connections, Peak/Power LED's, Gain control, EQ and Mono buttons

Next up may be Rockford Fosgate's most well known amp from the mid-80's to early 90's, the Punch 45. In 1991, Rockford updated their vulnerable Punch 45 to the Punch 45HD, aka "Hybrid Design". Again, many competitors in the late 80's/early 90's used a single Punch 45 to compete in the 50-watt and under class.

The 45HD required spade connectors for the power and ground inputs. The opposite side includes; speaker/remote connections via 6-pin Molex plug, Bass/Treble knobs, Left/Right RCA Inputs and gain controls for both channels.

(Top) Rockford Fosgate Punch 45HD's 6-pin molex connector, bass/treble controls, left and right RCA Inputs and Gains

The slightly smaller heat sink of the 45HD measures 6.6" long  x 8.6" wide x 2.2" high and carried an MSRP of $275 back in 1991 (reference - Car Stereo Review, July/August 1991).

Punch 45HD Ratings at 12.5 VDC (both channels driven):

4 ohms stereo - 22.5 watts RMS
2 ohms stereo - 35 watts RMS
4 ohms mono - 70 watts RMS
(not rated to handle 1 ohm stereo or 2 ohm mono loads)

More Specifications:

  • Requires external 15A Fuse, 20A can be substituted for "extreme" loads
  • Stereo, Mono or Mixed-Mono operation
  • 0-18dB Bass Boost at 45Hz, 0-12dB Treble Boost at 20kHz
  • 0.05% THD at rated power
  • Damping Factor - Greater than 200 at circuit board, greater than 50 at speaker leads


Now you've read about the ratings and specifications, do you have a choice between the two for powering a single 8" subwoofer? I realize these amps may not be well suited to drive subwoofers, but this is OldSchoolStereo and I'm taking the test back to the old school!! Luckily, I have an early 90's JL Audio 8W1 (4 ohm) which will be the perfect test sub for these amps. In addition to the subwoofer test, I'll also test resistive RMS wattage output from both amps at several ohm loads.

Now, the question I'm sure many of you are asking....did I have a favorite before the tests? Well, I must admit I've tested the Punch 45HD before and knew what to expect from this little "punch". That said, I had high hopes for the 222 SX based on how well the Orion 275 SX fared against the Punch 150HD and Phoenix Gold MS-275. This is a CLASSIC shootout as I expected the results to be very close. I can't go without saying I broke the rule of my YouTube channel saying I wouldn't do "woofer flex" tests. I just couldn't resist seeing how these baby amps pushed the JL 8W1. I also used my Zoom H4 audio recorder for GREAT quality bass without distortion. Just make sure you use your headphones while watching the YouTube video to get the best experience (well, unless you are watching this on your home theater with an 18" powered sub...)

I put the Orion 222 SX on the bench first and connected up the resistor bank, 1000Hz test tone and Velleman HPS50 oscilloscope/true RMS Volt meter. Results are:

Sunday, November 6, 2011

Rockford Fosgate PBR300x1 "Boosted Rail" Amp

Old School Orion 222 SX vs. Rockford Fosgate PBR300x1

As we all know, technology has a way of "shrinking" electronics over time. Have you ever seen an early laptop computer? Or how about a 1st generation iPod? Compared to the latest laptops and iPods, the first generation models are large and clunky.

Transition over to car audio amplifiers. Although this is, I still appreciate technology and have been eager to try out one of the new "mini" amps currently on the market. One which grew particular interest is the Rockford Fosgate PBR300x1. This amp measures a tiny 6-3/4"L x 4-1/4"W x 1-1/2"H, small enough to fit in the tightest automotive locations. Here are the full product specifications:

  • mono subwoofer amplifier
  • 75 watts RMS x 1 at 4 ohms (150 watts RMS x 1 at 2 ohms)
  • 300 watts RMS x 1 at 1 ohm
  • CEA-2006 compliant
  • Boosted Rail amp technology
  • Dynamic Thermal Management cooling system
  • variable low-pass filter (35-250 Hz, 12 dB/octave)
  • differential-balanced inputs eliminate noise from your vehicle's electrical system
  • preamp and speaker-level inputs
  • optional wired remote bass boost (0-18 dB at 45 Hz)
  • 10-gauge power and ground leads and a 30-amp fuse recommended — wiring and hardware not included with amplifier
  • no onboard fuses — when installing multiple amps in a system, an additional 30-amp in-line fuse between the distribution block and the amplifier is recommended
  • 6-15/16"W x 1-9/16"H x 4-5/16"D

  • Something I noticed immediately after opening the box was the inclusion of molex-style connectors for the amp. Am I missing something here or are we going back to the early 1990's? I couldn't help to think of the 1991 Punch 30HD which uses similar connectors. See pictures below for all of the connections, plus a size comparison to the 30 watt Punch 30HD.

    PBR300x1 connections including crossover, gain, hi/low input and Remote Punch EQ

    PBR300x1 Speaker output and Power connections

    2011 PBR300x1 vs 1991 Punch 30HD - 300 watts vs. 30 watts!

    Ok, so an amp almost small enough to fit in your pocket can deliver 300 watts? Well, according to the birthsheet included with my PBR300x1, it will actually do 315 watts RMS at 1 ohm (14.4v)! Impressive numbers from such a small amp, but how does it sound powering subwoofers?

    Well, you can see (and hear) first hand by watching my video below. I auditioned the PBR300x1 on my test bench with subwoofers including; 8" JL Audio 8W1, 10" Kicker Solobaric S10c and 12" JL Audio 12W6v2 D4. The results were impressive, to say the least. I'm really looking forward to getting the amp in my daily driver for a true test of this little beast and how it performs in the harsh automotive environment.

    Stay tuned for an upcoming power output test of this amp. Make sure to SUBSCRIBE to my YouTube Channel to stay notified of my latest video uploads.

    See the mystery "unboxing" of these Old School Gems below:

    Video in 720p HD

    or embedded below:



    Thursday, November 3, 2011

    Recent Arrivals to the Labs

    I've recently done several unboxings on my YouTube channel. I'll have more articles and tests in the near future, but for now, enjoy the videos!