PFA300

The PFA 400U amplifier is a Class D (Class T) with BTL output (to increase power out) which is non-inverting input to output, with 5 watts RMS output power into 8 Ohms. The channels are reversed input to output so to compensate either reverse the input RCA plugs or the output speaker connections. The tone controls on the amplifier cannot be switched out. The power can be switched off by turning the volume control fully off (counter clock wise). The remote can switch the unit to standby and the track being played will not be forgotten. The RCA inputs can be overloaded causing the amplifier to saturate. To prevent this, set the digital volume to 14 to begin with. The digital volume acts both on the RCA inputs and the MP3 player. The MP3 player has excellent response. Some amplifier BTL zero crossing error is present, as well as some low frequency distortion at 17 Hz, and some digitizing error above 1kHz. Overall the combination sounds “good”. Subjectively the amplifier and MP3 have enough adjustment range to adjust for personal preferences. I have noticed no noise output either with speakers or headphones. I play music at low volume levels (60 mW). All listening and measurements were performed with a Zitrades 12V4A power supply. As far as tone neutrality and distortion, this amplifier does not have a “direct” setting and will not compete with the Lepai 2020A+ or the Pyle PFA100 in this respect. Instead this amplifier is set up to offer more power and a variety of tone control adjustments with the MP3 equalization settings (5) and the tone controls to compensate for non-optimum speakers or non-optimum listening conditions when playing MP3 music. The Best 1kHz square wave presentation (with no overshoot and no sag in the waveform) is obtained from the amplifier with the EQ0 setting, the Treble about 11 0’clock and the Bass at 9:30 o’clock. The most uniform frequency response is obtained with the EQ0 setting, Bass at 9 o’clock and Treble at 2:00 o’clock. Caution must be used in using the equalization settings (other than zero which I use) since they are not designed to prevent digital saturation. In the era where digital music is recorded at the highest possible volume level short of saturation, the use of the equalization settings can cause saturation of the MP3 player output (typically from 61 to 500 Hz (bad)). Saturation introduces extra tones into the music (harmonic distortion). Lowering the digital volume setting will not prevent this. Personal preference will determine what is best for you. The MP3 player and amplifier combination has good frequency response from 17 Hz to 4 kHz, and response to 12.5 kHz, which as far as I am concerned is a minimum requirement. The phase error of the amplifier is far from optimum. The minimum output Bass phase error at 17 Hz is obtained with the Bass set at 1 o’clock. Treble phase response is unremarkable (about 90degrees at 10kHz) with minimum phase error at 1kHz. Do not look for stellar phase response from this unit. If you want better accuracy consider the Pyle PCAU15A amplifier and MP3 player combination (no tone controls). Monitoring the MP3 player output with an oscilloscope the response is basically flat from 17Hz to 20kHz with a sweep frequency (excellent). The 1kHz square wave response is textbook. The player loses lock on the square wave at regular intervals. There is good volume action in the PFA 200 (not overly sensitive for either the digital or potentiometer) with no potentiometer noise. The Noise output on the positive lead is 50 mV peak to peak of 715 kHz switching noise with 10 mV pp random noise. The Noise output on the negative lead is 50 mV pp consisting of high frequency components of ringing plus switching noise plus as small component of random noise.. The high frequency noise components are not audible. I could not hear any noise in listening tests. Power consumption with a 4A 12 v Zitrades power supply is 2.2 W at idle. Subjectively this unit has lots of adjustment to address loudness compensation, room response compensation and speaker compensation. There is good bass response to 17 Hz (with significant amplifier distortion at 17 Hz, with the distortion basically gone at 61 Hz). What settings work best for you will be trial and error based on your music source, your speakers and your listening area. This is probably not the ideal setup for critical listening under optimum conditions. All of the components of the PFA400 are on two PWBs (MP3 player and amplifier). The component side has both through-hole and surface mount components. There was considerable flux residue from hand soldering operations on the PWB. I cleaned the PWB both sides with alcohol. The operational amplifiers are surface mount. The Tripath IC is through hole and is clipped to a heat sink. I am enjoying listening to MP3 music with the PFA400U and my small refrigerator sized Bozak speakers. I use the stock 12 V power supply since I listen to music with a maximum output to the speakers of about 60 mW. The unit has as high convenience factor with the use of the remote.

Super-quality stereo amp for a reasonable price and I found an extra bonus! (Tell you later in the review.) I am really impressed with the sound quality for the price. The controls are basic but are useable and fairly precise. I hooked this small, well-made amp to some good-quality bookshelf speakers I had not used for years and got good low, mid and high-end response. I wasn't looking for ultra-audiophile response in a $30 stereo amp but I was very pleased with what it gives me. With an MP3/mini-jack, 1/4 in. mic jack, push-wire speaker inputs and RCA phono, it is adaptable to most any need. I'm not putting this in an auto, but you can do that if you want to. It comes with the power wiring for it (with a fuse holder.) What's the bonus? I plugged my electric piezo-pickup acoustic guitar into the 1/4 in. jack and the sound was really good even cranked up! I haven't tried running my (4) pedals into it yet but the guitar straight into the amp was hiss and noise-free until I had the volume up 'til around 80%, and even then it was acceptable. I think it sounds better and louder than my 15-watt acoustic Fender amp. Kinda wish I found this before the guitar amp! Minus? I can't seem to get it to work with my Android phone. I'll keep trying. Update 8/15/20: I had a bad mp3 cord. Found another and it works great with my phone!

This Amp is nothing special, which is exactly why you buy an amp of this type. It takes the signal, amplifies it enough to power a pair of smaller speakers (6 inch or smaller is best in this power range), doesn't have a large amount of distortion or noise, and isn't overpowered. Some would say that's a bad thing since I didn't say there is NO distortion or noise, and its not a powerhouse, but if that is what you are looking for, you are looking at the wrong type of product, and in the wrong price range. For most people, just looking to power a couple of speakers, who aren't going to nitpick everything, and obviously not in the "high end" audiophile market, this amp will probably work for you. Sound Quality - I am VERY picky in this area, and were I using for my main stereo setup, I would not be happy with it, but then again, that is not the type of setup this is for. It does have SOME, a very small amount, of audible noise, and a small amount of distortion at some frequencies/levels, but most people wont hear it, I have a trained ear and hear EVERYTHING. But the sound it puts out IS okay, and will sound good on most small speakers, or bookshelf size speakers. You can turn it all the way up without worrying about destroying your speakers and it does manage to this without distorting as much as many other amps will. If your looking for something to power a set of speakers in your garage, office, back yard, etc. this amp would do it just fine. Obviously its not going to push a set of 18" Black Widows, but it will give your ceiling speakers, bookshelf speakers, or small component speakers sound at comfortable levels from a decent/average source. I haven't tried the mic input to comment on that, but I am also sure it works as well given the fact this is a very basic Amp, and is just designed to work be nothing special, which means it does just that, works.

This is pretty damned great for what I'm using it for and price. I have 4 speakers in a room that is 50sm (about 500 square feet). The JBL Control NOW speaker system (they make a donut if you have 4). I'm not a audiophile, but I do have perfect hearing (even at my age 50+ I can hear sub 100hz, although feel is a better word than hear) and I peak out at about 17.6khz according to my ENT). Yeah, sure, there is some subtle static, the same I hear on most devices under $100. I specifically like to listen to music that involves one person singing into a mic intended for hearphones: Paul Simon, Lindsey Buckingham, etc. and it comes though very well off this. Audio is a very subjective issue at many levels. If you don't like this device because you have high standards, there are some great options out there that solve the small stuff with more and better circuits, and yes, you will pay more. This device is primitive keep in mind. One example is it remembers were you were last. So if you turned it off while it was set to loud, then the next morning when you power it up it will blast you. I would love a switch to control which way you like it. I plan to run tests on it, if you think of something you want tested tell me and I will update my review here with what I learn. Because this has a USB I bought this other cool solution "Sunweb Infrared Remote Control Receiver + Emitter + USB Adaptor for IR Extender Repeater " which is basically a sub $10 extender for the IR receiver. Works GREAT with this. I have used the SD card feature so far, works great, although I need to learn if there is a way to presort the music (perhaps force naming) or if it does one folder after another. I will mine other reviews and see if anyone knows the rules it uses.

While rated at 100 watts power (100 per, 50 per?), this amp didn't live up to expectations. It is a GREAT tiny amp with lots of uses, and the USB and micro SD card slots are very nice. Unfortunately, it just didn't cut the mustard and I couldn't use it for the purpose I intended it to fill. I bought it for my home system, based around my PC, which heretofore was run by an old (and much-loved, my first-ever expensive electronics purchase some thirty plus years ago!) Onkyo switchable integrated amp (or only pre-amp) at 35 watts per channel driving a pair of Bose 301s. This otherwise handy (and fairly nice-looking) tiny amp just couldn't drive my 301s. It should have been a cinch, given that at even 50 watts per channel, it still should easily have out-performed my old Onkyo, but I have found it useful only for driving much smaller bookshelf speakers (I have several pair, and it does handle them fine). Otherwise, even with the volume maxed out, it absolutely could NOT get my Bose speakers to provide the full, rich, invisible surround-sound to which I have grown accustomed. Hardly a waste of money, but it certainly did NOT perform as I expect an amplifier pushing 50 watts per channel to do. I think it's great, and it does a wonderful job with smaller speakers (although I have NEVER thought the 301s to be *power-hungry* before) but overall, I was disappointed and had to replace it. Update: found new use after re--arranging desk area, using it with small Sony 2-ways, listening to tunes on SD cards while surfin' the 'net. After about another year of use almost daily short use (can't stay at desk too long due to disability), it just quit. Won't even power up... Too bad. It actually was growing on me. Low cost initially, so 3-stars for average/adequate, rather than 4 (good) or 5 (great).

Works great ! We had a newer tv that lost it's speaker function (bad humming and loud static) since it's was just past it's guarantee we thought we were stuck having to buy another tv ..Not so....we bought inexpensive small Pyle bookshelf speakers and this terrific amplifier. We purchased the speakers along with this tiny amplifier which also saved us from having to buy an expensive receiver that might have HDMI connections so we could use any tv sound transmission to speakers. Additionally most newer tv's don't have component in and out hook ups so any receiver you might own must have HDMI or a digital connection and our tv didn't so we thought we were stuck ...But this amplifier has an 3.5 mm input jack we could use from the tv's headphone jack to the amplifier and out to the speakers and Whaala ! We've got great sound and no more loud humming from bad tv speakers etc. We saved a bundle and the sound is even better than ever ...total control over sound and we have two speakers far from the tv giving us greater sound without having to blast the tv from across the room to hear low conversations on the tv ...Good luck hope this info helps others..great product, great price.

First off, I bought this 90 watt to replace my 15 watt LePai that I paid around $20 for. The LepAi was making a buzzing noise in my speakers and started cutting in and out. The GOOD Sound is good, there is a minor buzzing if you turn the audio too loud but its not noticeable when your playing music or other sounds are coming out of the speakers. Feels durable, heavyweight and nice construction The BAD The MP3 jack on the front is TERRIBLY MADE. I have a standard auxiliary cord for my iPhone and it slides right out of the port from the mere weight of the wire. Really poorly made, if your using this as an mp3 player, look elsewhere. This might not be important to some people but there are no mounting holes anywhere on this thing. It has a stand but nothing else. Pointless if your using this for a car or if you want to bolt this too a desk (like I do) so I just used a velcro strip to attach it to the side of my desk. The volume nob is the same size as the other nobs. I have grown accustomed to the perfect setup of the Lepai amplifier and the volume nob is MUCH larger. Same with most other HiFi or mini amps. Its the nob you use the most, so why this would be the same size as the treble and bass nobs is beyond me. The volume nob is in synch with the speakers AND the headphone jack. Most good amps control the speakers only and leave the headphones at a medium level so the media can control the volume (like windows or a home entertainment set or television ) When you turn up the volume for your headphones, your speakers go on...... WHAT IS THE POINT OF THIS!? Editing my review as of 2/8/2013 The piece of crap product broke. Whenever I adjust the volume, it crackles and the volume randomly goes high as I am turning the volume. Sometimes the volume gets stuck on a really high decibel and I have to tap the box to calm down. It's basically garbage at this point and I am in the market for a better amp. I will never buy another Pyle again. STAY AWAY.

This is the second unit I have owned. Both of them are great and easy to use. Not to crazy with the way the power supply is implemented but it's cuts down on the heat of the unit. Powerful enough for the way it is used and sounds great!