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  • Kinter ma-170 mini stereo amplifier

    I know this is old news. But, I decided to order a Kinter MA-170 amp. Why? I wanted something dirt cheap for my home office. I wanted to assemble a cheap AV system.

    I have an older 20" Westinghouse LED monitor hanging on the wall, useless. I also have an older LG Blu-Ray player which happens to feature WIFI connectivity. And a pair of empty Dayton tower cabinets, in which I installed my car BZRK ODR-6.5" woofers and 1" silk dome tweeters. All I needed was a cheap amp to tie everything together.

    I bought the Kinter for under 10 bucks! Free ship. Next day delivery. I did not want the $16 Kinter amp set with included power supply. I already have an older Insignia TV power supply ( 12VDC OUT @ 5A).
    I also have a good quality stereo cable with 3.5mm stereo plug to left/right RCA plugs.

    I now have a complete AV system for my home office, for $10. With the LG DVD player I can play DVDs, CDs, or use wireless connection for several music apps as well as watch Netflix.

    So, what do I think of this amp...
    It sounds fine. It pushes the speaker systems easily. The speakers are wired in series (8 ohms:woof, 4 ohms:tweet). Crossover is the BZRK 12dB @3.5Khz.

    I tried various music, ranging from deep emphasized bass to clear vocals and detailed highs. I can't believe how good this amp sounds, inspite of all the criticism it has received.
    Bass is as full as the speakers are capable of delivering. Mids are fine. Very distinct treble. Excellent stereo separation and imaging.

    I set all tone controls flat (Approx center point on amp, Bass/Treble) and flat on the monitor's built-in 7 band EQ (except for a -3dB attenuation at 200Hz).

    The LG DVD player is connected to the monitor via HDMI.
    The monitor is connected to the Kinter via headphone jack.
    I set the Kinter amp Volume at about the 10:00 position, to minimize distortion.
    I use the remote for the monitor to control Volume Level.

    I typically play at lower volume. However, I tried moderately loud output, loud enough for my wife to hear the bass thumping downstairs.
    I heard no distortion. No clipping. No degradation in sound quality whatsoever.
    I also heard no pop/thump on turn-on.
    I heard an attenuated double thump on turn-off.
    With no source, monitor volume up all the way, I heard no noise. No hiss. No electric static.

    I'm sorry, but, this amp is not bad at all. In fact, I am pleasantly surprised. Fidelity is much better than I anticipated.

    I owned several of the Lepai 2020 T-amps years ago. I gave one to my great-nephew, who uses it to this.day. A great amp to be sure. I get the comparisons made in reviews from years ago. However, that amp is no longer available. So-called similar amps do not stack up to the original. Many mini amps now sell for $50 or more. So, by comparison, this $10 Kinter is an amazing deal.

    I also tried a rip-off China amp with brand name I did not recognize. The amp arrived DOA. Useless. At least Kinter has been around a while. Since the intro of the Lepai sensation.

    For what it's worth, Kinter seems to be improving, which is good. IMO, This amp is great for any dorm, bedroom, office or garage. This amp could probably perform satisfactory as a main amp in a living-room AV system, if loud volume is not a prerequisite.

    This amp received some criticism due to its outdated AB chip design. Who cares? It's $10. And AB amps have been around a long time. Back in the 70's/80's, my Pioneer receiver was an AB push-pull amp. It's output was clean, less than 0.06% THD throughout the entire bandwith at rated power. Not the crap "less than 1% THD+N" of modern amps, which would have been considered unacceptable back in the day. There is nothing wrong with AB designs. Digital is not neccesarily better. AB amps deliver low noise clean output.

    Reviewers even criticized the color changing LED ring around the Volume knob. Idk why. I'd prefer a basic LED on/off light. But, this isn't bad. It is subdued. Even in the dark, it is not annoying. In fact, I seem to remember the original Lepai amp with an annoyingly ultra bright red LED ring around its Volume knob.

    This Kinter MA-170 gets an undeserved bad rap. In smaller rooms, it can easily drive bookshelf or larger speaker systems to satisfying levels. Sound quality is quite good. Detail and nuance is surprising. And this amp is only $10, if you happen to have a power supply on hand. You couldn't build as nice a looking component for so cheap. In fact, you'd be hardpressed to spend under $10 at a fast-food drive-thru for lunch lol.

  • #2
    It looks like PE isn't going to be selling Kinter any more.
    I wondered about them... they were almost two thirds the price of Lepai so I kind of assumed that they were not too good.

    Of course decent amp boards can be had for 2 to 3 bucks from overseas so...

    Thanks for the full review, I like the mini amp format. I bought a few of the Dayton micro amps when they blew them out a few years ago,, I like them. Dta 3116S it was. I think the novelty of such a small amp producing real sound on real speakers is just a cool thing too.

    TomZ
    Zarbo Audio Projects Youtube Channel: https://www.youtube.com/channel/UCEZ...aFQSTl6NdOwgxQ * 320-641 Amp Review Youtube: https://youtu.be/ugjfcI5p6m0 *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
    *Part 2 *Gluing multiple curved laminations of HDF

    Comment


    • Stash
      Stash commented
      Editing a comment
      Yes. They are a sort-of novelty. Yet, they have a definite niche. As a background music source. As an inexpensive second or third sound system. As a space saver.


      The 3116 chip is decent. Good all around performance. I read the Kinter uses a TDA7266 chip. One reviewer claimed the chip is a Sanyo. I will open it up later today. I'm curious myself.

      I know these amps aren't true hi-fi. But they come fairly close. They are definitely listenable. When I relax in my office recliner and turn on that tiny amp, I'm not critiquing the system. I just close my eyes and enjoy the music. And, knowing this little hodge podge AV system cost me next to nothing, is most satisfying.

      Compared to the mini amps and car booster amps from my heyday, this Kinter and others like it are light-years ahead in sonic performance. Wider flatter bandwith. Less distortion over a wider range. Less compression. When you don't need, or cannot afford, a hi-fi receiver or amplifier, these little amp boards are a welcome alternative.

      I wonder why PE will no longer carry these amps? Maybe competition. I can't believe I spent 10 bucks and still received free delivery the very next day.

  • #3
    I have an old Lepai that looks just like the Kinter. Very noisy when turned up, but otherwise great for applications where you want cheap amplification. I'm currently using one with my Soundeasy test setup, though I plan to replace it with something much quieter once I figure out how to work the software.

    Comment


    • Stash
      Stash commented
      Editing a comment
      I'm surprised your Lepai is noisy. Could it be the power supply?
      This Kinter is extremely quiet. I happened to have saved an old TV power supply from an Insignia TV which was damaged. Works very well with this Kinter amp.

      I had owned a couple of older Lepy amps, which were a rip-off of the Lepai and not nearly as clean output. They were noisy. But, I concluded some of the noise.was due to the included power supplies.

      IMO, your better off ordering an amp, by itself, and mating it to a better power supply. I would choose a 12VDC supply made for a TV. They are more likely designed to introduce less noise, since TVs tend to be sensitive. And they may be slightly more powerful. As I mentioned, my TV power supply is 5A. That's around double the 2A or 3A small power supplies which are furnished with many of these mini amps. And probably better insulated as well.

  • #4
    It seems that the Kinter MA-170 is dumpster fodder.

    Originally posted by tyger23 View Post
    First things first:

    THANK YOU PE! I was a winner in the Kinter amp giveaway, and I was lucky enough to receive an MA-170. I was excited by this, because it looks to be a true competitor to the Lepai LP-2020A+.

    That being said - run away. Buy this for the case, knobs, and connectors and throw the rest out. I'll try and break this down into sections:

    Chip amp inside = TDA7266
    First off, I was unable to determine the actual amp inside the MA-170 from PE's website. So, I tore it apart. The chip amp is bolted to the side using a thermal pad and two screws, and it's an ANCIENT ST Micro TDA7266. This is a class-AB amplifier with rather poor efficiency. It's been long surpassed by many amplifiers since, including just about every Class-AB or Class-D amplifier produced in the last ten years. The TDA7266 was never rated to support 4-ohm loads, but it can with thermal limitations. The actual Kinter MA-170 accepts a 12V input, but immediately includes a large diode (1N5401) in the power path, dropping a 12V input down to roughly 10.8V. So, as we look at the TDA7266 datasheet, we can see that it's mostly rated for 8-ohm loads with an 11V VCC, which is exactly what the Kinter is doing. Check out the spec for the amp here:
    http://datasheet.octopart.com/TDA726...t-10032338.pdf

    At 8-ohm loads, this amp is only capable of about 6W/channel at <1% distortion and about 8W/channel at <10% distortion. The amp is going to be thermally limited at around 7W/channel into 8-ohms according to the datasheet, so even with a 4-ohm load, the most you'll get out of this thing is about 8-10W/channel (not the 20W that PE is advertising).

    Regarding the distortion - the TDA7266 is an OK part, producing less than 0.2% distortion across the frequency range for most of the "usable" power band. This isn't bad, but it pales in comparison to newer amps available today, including the LP-2020A+.

    Turn-on Pop
    It has one. A really, really disturbing, loud one. In fact, it's about 2 pops in short succession. This could cause damage to some speakers. Fail.

    Turn-off Pop
    Yep, there's two of those as well. Not nearly as disturbing as the turn-on pop, but definitely present. Fail.

    Volume Control LED
    This thing varies from red-to-green-to-blue-and-back again. You can't control the color, brightness, or anything about it. Not a deal-breaker - I just want people to know about it.

    Volume Control Usability
    This was a bone-headed design move in my opinion. For some reason (likely costs due to BOM control), they chose to use B-taper (linear) pots for the Bass, Treble, and Volume controls. While this doesn't really matter as much for the contour circuits used for the bass and treble controls, this is horrid for a volume control. Basically, using a linear taper pot for a volume control means that 60% of the pot is going to be useless, then you'll have very little accuracy control available once you start to near a usable volume level. In other words, you'll start turning the volume knob up and hear very little change until you've suddenly blown past where you want the volume level to actually be. Fail. Use an A-taper for volume controls!

    Bass and Treble Controls
    IMHO, the previously mentioned items could be overlooked, provided the end-user is aware of them and how to get around them. Unfortunately, the bass and treble controls provided on this MA-170 cause irreparable damage to the audio.... These things are passive component, very wide bandwidth filters that have no bypass whatsoever. The markings on the dial are listed as -10 at the low end and +10 at the high end. Unfortunately, there's no center detent to the pots, and there's no audible "defeat" that can be obtained by placing the pots near the center. They seemingly make large changes to the audio and any setting. This is not unlike the original LP-2020A+ amplifiers, but the difference here is that the new LP-2020A+ amps include a "tone bypass" button that bypasses the tone controls. Such a feature on the Kinter would be a welcome addition. As it is, I would have to re-work the existing board to manually bypass these controls to make this amp even close to "usable". Fail.

    RF Immunity
    Yeah, move along. Nothing to see here (as in - there is no RF immunity). I had my Verizon iPhone close to this thing (using it as a source) and the GPRS buzzing was almost intolerable. The designers obviously did not put any thought into RF immunity on the amplifier inputs. Fail.

    Power Supply
    It doesn't come with one. It doesn't advertise that it does, so this is no big issue. I thought I'd take the time to provide my thoughts on what power supply SHOULD be used with this thing, if you so choose to purchase one. Basically, the amp will do about 7W per channel with 70% efficiency. This means that you need about a 2A power supply at 12V to push this thing to it's thermal limits. 2.5A to 3A may be slightly better, but you're bordering on overkill for this.

    Build Quality
    Believe it or not, this thing is actually built quite well. I saw no cold-solder joints or possible issues, and this thing far surpasses the LP-2020A+ in that regards. The little aluminum case is quite nice (just like the LP-2020A+ but smaller), the chrome plastic knobs are nice, and the rear panel connectors seem to be of decent quality. Kudos in this department.

    Overall Sound
    Well, the inability to bypass the tone controls completely kill this thing for me. Despite the lack of power, the pops, the lack of RF immunity, the crazy LED, and the nearly uncontrollable volume knob, this thing could be usable with a bypass on the tone controls. Sadly, it doesn't feature such a bypass, and it will require manual soldering work to bypass them internally.

    Verdict
    Well. Fail. Buy it for the case, buttons, and connectors, but toss the amp.

    PE sells the MA-170 for $10.40, and a suitable power supply (120-052) will run you another $12.95, bringing the total to $23.35. A Lepai LP-2020A+ which features a proper volume control, tone bypass, more power, and an included power supply costs $26.88 (currently) and represents a far better value for the money.
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    Comment


    • Stash
      Stash commented
      Editing a comment
      I read this review. I actually hesitated to buy the amp after reading the results.

      But, I am happy I took a chance on the Kinter. It is not nearly as bad as claimed therein.

      My amp makes no pop/thump upon turn-on.
      An attenuated double thump on turn-off.
      Very low noise. Inaudible to me.
      Relatively clean power output at low to moderate volume.
      No audible distortion nor clipping at normal listening levels.
      Relatively wide power bandwith, 100Hz-20Khz, flat and 20Hz-20Khz, -3dB (re: data sheet, TDA7266SA).
      Excellent stereo seperation.
      Decent bass output. Detailed refined treble.
      Pushes 8 ohm speakers easily. Doesn't even get warm.

      Complaint of lack of bypass switch is ridiculous. No real need for critical listening such as when selecting discreet amp mode. (And, yes, I know the Lepai included this option). Alas, the Lepai is no longer available.

      The Volume pot is not stable or concise. Well, it still works. My Kinter amp is playing fine. I notice no major discrepencies. I adjust the volume via my TV monitor anyway. As long as there's no static or noise from the Volume pot, who cares? Really?

      And the color changing power LED is also fine. Not overly bright nor distracting.

      IMO, this "fail" review of the MA-170 is nothing more than bandwagon politics. The $10 amp receives multiple horrendous reviews from people who wish to fit in, visa vie trashing the product. It's fine to point out the amp's shortcomings. But, again, I reiterate, this amp was $10 out-the-door. That's it. Let's face it. This amp costs me about the same as the sales tax on a full size amp/receiver. For ten lousy dollars, this amp performs remarkably well. When I close my eyes and listen to this amp, I do not hear a poorly chosen pot or lack of bypass. I only hear fine music. Sonically speaking, at low to moderate volume, I doubt this amp sounds audibly worse than similar sized amps costing 4-5 times the price.

  • #5
    I think sometimes quality control on some of these 'lesser' amps is not what it should, or could be. There were noise complaints on the little amp I mentioned as well, but I've used three of them so far and they have all been dead quiet. Others have had issues apparently. I have a few more up there in the closet and who knows, one of them may be noisy, but so far so good for me.

    I remember reading Tyger's review way back when on the Kinter amp, that may be why I passed on it. Looking at things in a super-critical light can show up all the little warts, but I tend not to (or try not to) notice stuff that much. Class AB sound with low distortion at a reasonable 6-7 watts is really all you need for many listening situations. It may end up sounding a little 'warmer' than even more modern Class D amps sold today.

    I'm still in the "I'm Amazed" camp when it comes to tiny electronics like this. I'm filled with wonder each time I test out an amp board that is half the size of a credit card, but produces good sound at decent volumes... tiny cheap Bluetooth boards that produce good, clean audio... small MP3 playing preamp boards that play video on tiny screens.... compared to what I had to work with 15 years ago it's practically miraculous!

    TomZ
    Zarbo Audio Projects Youtube Channel: https://www.youtube.com/channel/UCEZ...aFQSTl6NdOwgxQ * 320-641 Amp Review Youtube: https://youtu.be/ugjfcI5p6m0 *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
    *Part 2 *Gluing multiple curved laminations of HDF

    Comment


    • #6
      I'm pretty sure the 2020Ti is still available, and sounds great!
      Wolf
      "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
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