Sonic Impact Super-T Amp (audio review)

The Sonic Impact T-amp, once available for as little as twenty dollars new, may be the only electronic item ever sold at Target that audiophiles ever took seriously. Apparently the manufacturer never had high-end pretensions, they simply marketed the amplifier as something to take to the beach with a small set of speakers so one could listen to whatever was on the Ipod with a group of friends.

Much to the company’s surprise, the battery-powered amplifier in the cheap plastic case sold out its first production run after it was discovered by audiophiles who began to use the internet to praise its surprisingly good sonic performance. A sub-market sprang up of people who were sometimes spending hundreds of dollars to modify the things (see Redwine Audio before the guy screams at me, Redwine does more than just modify the T-amp). Even though this kind of modification sounds crazy, it's a good thing. Tinkering or Poogeing (the Old Audio Amateur magazine once ran a series by Walt Jung and Richard Marsh for the Professional Order of Golden Ears (Pooge)) is an honorable tradition in hi-fi. At the same time, I have still never seen anyone on the beach, in a park, or anywhere else for that matter break out a sonic-impact T-amp there and hook up a pair of portable speakers.

There are reasons the boom box remained popular for so long. One of them was that ordinary folk don’t necessarily care to run speaker wires and set up four different items when they tote their music system. I’m not privy to the marketing figures, but I have this funny feeling that the product would have disappeared had Sonic Impact had to rely on its original intended market.

Responsive company that they are, Sonic Impact has introduced the Super-T amp, a new $135 version of their class D amplifier in an attractive aluminum case with gold-plated RCA’s and proper binding posts. They’ve also made some of the internal changes recommended by the hi-fi hot rod crowd like improving the coupling capacitors, but for the most part the basic tri-path chip circuit remains the same.


This is a bit like Honda offering a street-racer ready version of its two door Civic with performance chip, NOS booster, and wider tires all suddenly bundled for twenty five thousand dollars. At one level, it makes perfect marketing sense. If kids are spending upwards of twenty thousand dollars additional to modify a stock Civic in their garage, wouldn’t they rather have most of those performance enhancements crammed into a factory-ready package for half that?


I suspect the street racer spends thirty thousand dollars on a Honda Civic at least partly because he/she likes the pride of taking something off the shelf and both improving it and having something unique. They don’t necessarily want to buy the factory version as much as they want to “outdo” it. The whole tradition of hot rod hi fi from Dynaco, through Hafler, NAD, Audio Alchemy etc. has also been the plain brown wrapper thing. You give up cosmetics in exchange for high quality innards that can potentially be continuously upgraded at home. In fact, the mantra goes something like “This sounds every bit as good as …… I just don’t need to pay for the cosmetics or the snooty high-end shop that serves espresso in its listening room, because it’s all about the sound to me.”

In the meantime, the class D hobbyist market evolved considerably over the last 2 years. If you look over at Diy audio forum, you’ll find a bunch of alternatives to the Sonic Impact t-amp aimed at the Do it Yourself crowd. There’s the Charlize, the Amp 6, the UDC (based on a different chip said to be superior to the tripath) and god knows what else. In the pre-built market, there’s now the Trends Audio TA-10, a Hong Kong company which doesn’t yet have a U.S. distributor, who went for a plain brown wrapper look and a more mod-friendly design than Sonic Impact’s with most of the parts easily removable.

At a marketing level, it'll be interesting to see how well Sonic Impact does with its first product not encased in plastic. For non-audiophile sorts, $135 dollars is a lot of money for a 7 watt/channel integrated amp with one input. They don't necessarily understand either the quality issue or the fact that the Super-T is arguably a better value than the basic-T. The company also apparently also have plans for a 50 watt per channel class-t amplifier in the $300 range some time later this year. That should be very interesting. I still haven't heard a higher power class-D amp myself, but am not the only one wondering if the magic will stay as the power goes up.

So What's It Like?

If you were going to modify the original T-Amp, there's no doubt that it would cost you a lot more than a hundred dollars to get it to the level of the Super T-amp. The product remains a bargain from that standpoint. When I took mine out of the box, I was definitely impressed. At $135, the Super-T sells for less in inflation adjusted dollars than either of its spiritual ancestors, the NAD 3020 (roughly $175 back in 1979) and the tubed Dynaco SCA 35 ($104 in 1964). It sounds and looks dramatically better than either of its predecessors. See, progress is possible at least in some realms.

I imagine the first question for most would be how does the Super-T's sound compare to the original Sonic Impact? The short answer is that it sounds better. For one, the original had a very steep roll off below 100 Hz. This made perfect sense for its intended use, low quality portable speakers. The Super-T has much better bass. Obviously it's still a 7 watt amp (okay the company claims 15 but that's into 4 ohms and even that is optimistic) so I wouldn't use it to power a subwoofer, but you'll notice a clear difference with say a reasonable efficiency 8" 2 way. One result is that the Super-T sounds "bigger" than its cheaper brother.

Michael Mardis has mentioned that the T-amp has a certain coldness in the vocal range due to a lack of detail in that region that he noticed after extended listening. It's a bit pardadoxical for several reasons, one being that Mardis is a big fan of class D and many people love the Sonic Impact because it reproduced so much detail. One of the frequent comments was that the sound from the amp revealed the "layers" in a musical performance. Instead of hearing say four different instruments coming off a flat screen, the T-amp manages to give enough of a sense of the dynamics and tonal differences between instruments that one gets a sense of depth and air. My own comparison was to the dough in good bread vs. the rubbery textureless nature of plastic-wrapped supermarket loaves.

Well, I have to agree with Mardis and the others on this point. Mardis by the way blames the presence of a fourth order filter in the amp itself mostly used to reduce noise. He also claims that the Trends Audio amp (I haven't heard one yet) doesn't have this problem which would suggest that the problem has nothing to do with class-D or the tripath chip and that it's more a matter of implementation.
I'm in no position to dispute that, but I've noticed with both versions of the T-amp that either some musical quality is there or it's not there at all. Unlike older tube amps which approximated say bass transients without actually reproducing them or early transistor amps that did whatever the heck they did to make high frequencies wiry sounding, the T-amp gets to some boundary of certain kinds of musical detail and it then just quits.

One of the glories of the Super-T is that you can hear fingers touching the body of stringed instruments and occasionally even sort of get a sense of how a singer is opening his or her mouth. At the same time, there's a kind of quavery quality to voice that lets you know that it's a person with vibrating larynx instead of say a synthesizer or an instrument of some kind that I'v heard other amplifiers do better. I also have no idea why the T doesn't reproduce some of this and yet gets so many treble and upper midrange details. Before you go off and say "Well the Super-T just isn't for me then....", I have to mention that it's amazing that one would even be talking about issues like this in budget-level stereo equipment. The NAD for instance was a big seller and as pleasant as it sounded, there was no treble detail to speak of. Items like the Dynaco 70 or Stereo 35 did certain things well, but they also did many basic things very obviously wrong.

I have to get off this path though. Whenever I start talking about "parts of sound" I tend to become more of an Audiofool than a music lover or even an audiophile. I've always found the best way to turn off the Audiofool is to simply pay attention to how much I listen to the stereo with component X in it, how much I find myself want to listen, and what I start listening to.

Since the Super-T has been in my house, I've listened to a lot more music. When I stuck it in the big system in the living room and replaced my mid-fi Parasound 1200 with it, my wife made a point of commenting about how great the music sounded. Actually the Aria 3 speakers I have in there (Accuton-Ceratic tweeters and mid with Cabasse woofer) aren't efficient enough for the Sonic-Impact so the treble was a bit hooded and the bass was on the rubbery side, but yes there's a kind of presence to the Super-T that one notices.

I find myself listening to less symphonic music, possibly because the transients are a bit too challenging for the limited power of the amp. It is very good, however, at catching the differences in tone and placement of the sections of the orchestra and their interplay. As great as the detail is, it also tends to break down a bit when the music itself is very very thickly textured. I notice myself reaching for lots of string music, quartets, bluegrass. Jazz percussion comes across really well as does most small ensemble jazz. The Super-T is especially good with woodwinds. Don Byron's clarinet for instance sounds appropriately woody yet doesn't over resonate, supposedly the sign of very good management of intermodulation distortion.

I also found myself rediscovering Paul Simon's Hearts and Bones album from 1982,which has very detailed instrumental textures.
The amp rather surprisingly managed some things like a bass drum skin sound in "Numbers Get Serious" and the wispy sounding string/synthesizer textures in "Late Great Johnny Ace".

As long as I keep the Super-T away from the things it doesn't like to do, there's a liveliness to the music and a sense of pace (sorry to sound like a Linnie) that few budget components manage.

I liked it enough that I dropped the Super-T into my "good"system, a pair of Scanspeak 6.5 " two way speakers with a Canary Audio tube Amp and a Sony ES CD player (okay I haven't bought equipment in a while). I found myself hanging out there for hours listening to acoustic guitar records and vocal ensembles. With the Scanspeak, I did find that the Super-T tended to be very sensitive to high frequency sins in bad recordings. That's actually a good thing, it's just hard to listen to the truth sometimes. Cymbals for instance become more pots and pan screechy than bell like. With really good recordings, they went back to being resonant.

Is it good enough to live in a "serious" system? No. (it might be very intersting though as the top amp in a bi-amp setup) Could I live with it as my only amp? Yes. Is it four times better than the basic-T? No...all in all it's pretty similar. The Super-T sound has more apparent guts, better bass, and I think a bigger soundstage, but its virtues and shortcomings are more or less the same as the basic-T. Is it worth a hundred dollars more? Absolutely. If you wanted to make the same changes to the Basic-T it would cost you at least that to replicate the Super-T.

Is it great for a multimedia system or a second system? Absolutely.
My guess is that if you do, you'll find yourself listening to a lot more music say while at your computer. That's what's happened with me. You might not get as much work done, but you might have more fun doing it.

I wouldn't recommend this to the guy who wanted an amplifier for his motor scooter and who complained about my review of the basic-t. I would highly recommend it to anyone who likes acoustic music at reasonable volumes. The Acura might just be a Honda Civic at heart, but for whatever reason, it's more fun to drive.

chancelucky