Product: Sonic Impact T-Amp - Class T integrated amplifier
Manufacturer: Sonic Impact Technologies - USA
List price: 39 $ (thirtynine)
Reviewer: VV.AA.
Reviewed: work in progress, 2005

There's no doubt our review of the T-Amp caused a stir (and some brainstorming too). After the review has been published, the tiny amplifer has quickly become sold-out everywhere and even the manufacturer (Sonic Impact) has been out of stock for a long while.
Anyway, since we always suggest not to take our words as gospel, we have decided to publish brief reviews of the "giant-killer", reviews written by average audiophiles. If you have listened to the T-Amp, under "proper" conditions, and wish to share your experience with the audiophile community worldwide, feel free to send us 10-15 lines (Subject: T-Amp review) of text containing: a brief description of the system used and of T-Amp ancillaries (power supply, cables etc.) plus your personal findings.
Everything will be collected into this article. Being opinions written by audiophiles worldwide, they not necessarily reflect our findings. New ones added on top of this page, older ones stay on bottom. Enjoy!

I just thought I'd add my comments on the wonder that is the T-Amp. I've been running it with the "T-Preamp" for a while through my Norh 5.1's, and despite its lowly 15W, the combination was sounding very sweet. I'd been thinking about trying it with some more efficient drivers though, and when a pair of cheapish Fostex FE127's showed up on ebay, I jumped on them.
I spent yesterday cutting out some new baffles, and I've spent today pulling out record after record and CD after CD, a great big smile on my face... Tone (especially vocals) is wonderful, I finally understand what dynamics are all about, and the imaging and soundstage is incredible - if I close my eyes, the walls of my room just melt away. The only place where things aren't quite as good is in the bass - although what there is is wonderfully smooth.
I've got the parts for one of the standard modifications on Michael Mardis' website though, so I've just got to build up the courage to take a soldering iron to it. I'm still looking for a pair of larger drivers (maybe the FE166/7's) as well, and I'll be very interested to see how they compare - I might even try and build a properly proportioned set of enclosures.
Seeing as the chip is so cheap, I wonder if/when it will make it's way into micro/mini systems? I know the idea of a really high quality sound from an off-the-shelf mini-system seems rather unlikely, but the T-Amp changes everything. The manufacturers really don't have any excuse now.
Anyway, many many thanks for writing about this incredible little amp and helping to bring it to everyone's attention.
Yours,
Philip - E-mail: philip (at) fishwinker.co.uk

I bought my first T-Amp after reading the TNT Audio review. Having recently bought a £250 Cambridge Audio amp for my main system, I bought the T-Amp mainly out of curiosity, and as it was only around £30 from E-bay, it seemed a cheap way of seeing how good it really was.
Anyway, to cut a long story short I've been very impressed. When the first set of AA battreries died, I bought a 12v sealed lead acid, which I found can kill a T-amp quick if connected up incorrectly. Anyway, I bounght two more T-amp's and decided to make better use of the multimeter. I have now sucessfully reboxed my T-amp into a maplin enclosure, with new speaker connections, and upgraded it to have 4 inputs (had to hack off the little input connector from the pcb). I would like to add VU-meter's and a battery indicator (ideally both analogue needle type displays), but i've got to wait for the weekend on that.
I also have a 47k dual gang pot on order from maplin to solder in at some point. Anyway, i'm using it now with the Cambridge audio 540c v2 cd player, and Mordaunt short 902i, connected with a TNT FFRC lead which I made up, and it's the first time i've heard the speakers dissapear, and the music flows seamlessly to my ears.
I find that my cd's are now sounding better than my vinyl's (using Project RPM4 and Project phono stage) although that sounds pretty good as well now. I could rave on for hours about how much I love my system now, and that I can't imagine ever buying another commercial amp (or speaker cable for that matter). If you haven't heard what a T-amp can do, i'd highly recommend the experience. I'm off now to buy more cd's!
William - E-mail: William.Innocent (at) cgi-europe.com

Dear Lucio,
I read your review of the Sonic T Amp, I was intrigued, I bought one (on eBay from a US seller, cost including shipping to my door in Scotland £27.40, delivery took 5 days). THANK YOU !!!!!!!!!
I haven't stopped smiling since I got it. I also haven't stopped singing along, tapping my feet and sometimes even dancing. It's small, made of plastic, and let's be honest ugly, but damn does it play music. All kinds, it doesn't seem to care !!!
I'm running it in at the moment connected to my computer. Using a pair of small bookshelf monitors and a 12v ( 7.2 Ah ) battery from a UPS as a power source. Listening to mainly CDs ripped using Media Player in Windows ( WMA ) Lossless format.
When time allows I'm going to try it in place of an Audiolab 8000 in my main system ( or what was my main system since I bought the T amp !). Teac T1 Transport, Audio Alchemy DDE v1.0 Dac and TDL RTL3 speakers. My listening room is medium sized and my usual listening volumes are moderate so I am hopeful.
And. yes I am going to try it using the 8000a as a Pre Amp feeding the Sonic T. The concept of trying a £500 amp as a Pre Amp for a £30 amplifier is a bizarre one, but the Sonic T has challenged (if not destroyed) all my preconceptions of what constitutes "hifi" and made me smile whilst it did it. I've got to try it.
Just the thought of possibly being able to BiAmp my system for another 30 bucks makes me laugh out loud.
I thank you again Lucio.
May I also thank you for the TNT website.
Regards,
Graham - E-mail: graham.walker (at) ecosse.net

I hope this is of some interest, and thanks for introducing me to this fantastic product, and the web-site in general. The following is a list of modifications I have used to substantially improve the performance of the stock T-amp, as well as addressing the most common problems of lack of bass and dynamics. This set-up now comfortably outperforms my $3000 transistor amp on all fronts.

1. A 13.7v 4a regulated psu made for industrial use by RS Components bought s/h for £20.00 from a surplus store. (much better than the equivalent Maplins psu)
2. Replace stock power cable on above with an audiophile quality one. (Russ Andrews Reference in my case I had from my old amp)
3. Replace cheap power cable between psu and T-amp with a high quality custom made one. (Revelationaudiolabs made a superb 6ft one for me from their ultra-pure cryo treated solid silver conductors for $110)
4. Clean all connections including contacts on the potentiometer inside the amp. (carefully remove wiring loom from white plastic container) with De-Oxit and treat with Walker Audio SST Extreme silver contact enhancer sparingly.(especially the pot leads)
5. Apply a small square of Stillpoints ERS paper to the underside of the T-amp cover above the chip (suggested by steely3 on diyAudio.com) and remove the battery cover and place another piece of ERS below the amp.(be careful not to use too much as this can worsen the sound)
6. Use small spade connectors on the speaker cables- one prong will fit into the spring clips with the other prong above or below when mounted vertically.
7. Blu-Tak to keep the amp in place.

I have read many reviews about the T amp and I think the word needs to spread about the diy available from the audiodigit & autocostruire websites concerning the new regulated power supplies. With these ancillaries you can enhance the sound quality of the T amp. I have Three T amps and one is configured with the autocostruire power supply this amp is the best not only for listening but as a tool for testing interconnecting cables speaker cables sources and the list goes on.
The T amp is so revealing that you cannot afford to make the mistake of no owning one that is if you are truly serious about listening to music. I discovered that a pair of interconnects from mapleshade flush out the bass of an unmodified T amp. I have to go work now so I have to end this. But it is the one great product of this century.
Richard - E-mail: richard.nemeth (at) usar.army.mil

I imported my T-Amp from Thinkgeek for a total of about £30 for use with a pair of Stax SR34 electret earspeakers. The power supply is a regulated 2A 13.8V box from Maplins, to give a total for the amp of around £50. The signal is taken from the outputs of a VTL deluxe preamp with the T-Amp volume control set to maximum.
My initial impression of the sound is that it has a very natural presentation of detail, if not quite the range of tonal colours of a good valve amp. However, the very fact that it has any tonal range is remarkable for a SS amp, let alone one this cheap. Bass goes very low, but loses out to my Concordant Quad IIs on dynamics. Above all, though, it is enjoyable to listen to.
Ultimately, this isn't the best amp in the world, and it would be unfair to use it on my ESL63s, but for the money it is a massive bargain. If this is what can be achieved from a simple implementation with cheap passive components, then Class T is something that is definitely worth manufacturers and DIYers pursuing.
Stephen - E-mail: steveaxcell (at) yahoo.co.uk

I have been using the amp for about six weeks now and can honestly say that I have not encountered a piece of audio equipment that provides so much for so little. I installed it in my "computer" system, this consists of a Marantz CD-52SE, Nakamichi 481Z and the output of my Mac via an M-audio Ozone connected by USB. The speakers are JBL Control 5's used more or less like near-field monitors. I am running the amp from a 1200mA 12V supply and switch using a 4way switch from Maplin (not the last word in hi fi but better than swapping plugs). The volume level is seldom very high so the output is not really an issue for me and it is always left powered up.
The financial burden was a very small 48 UK Pounds for amp and ancillaries. The main problem I have now is distraction, the resolution of detail is very high and I find that what was formerly background music now demands attention. The amp makes music and reminds me of my Sugden A28 in that respect. Voices have life. Complex electronic music falls wide open allowing any element to be followed. Different acoustic guitars have individuality. The most important aspect for me has been the fact that I have not grown tired of listening to this amp.
I thought that there might be some sort of psychoacoustic trickery/ novelty involved that would become increasingly tiresome ­ this has not been the case.
Of course, I had to try it with my main system, Revox B100 series tuner, cd & amp + Nak 660ZX & Michell Focus, SME 3009 & Shure running through Triple T to old Kef Concertos. The results were not so good, the speakers are too inefficient to exploit the T-amp. Fortunately in some respects as I don't think I was emotionally quite ready to replace my trusty battleship B150 with this plastic upstart just yet.
Finally, a friend has made up a very good sounding wireless multiroom system using T-amps and Apple Airport technology, for a couple of hundred Pounds a room and no drilling there is nothing to touch it.
Paul - E-mail: paul (at) nepto.co.uk

A tiny box that produces good sound at a very cheap price. Am I surprised? No, not really, in fact I'm wondering what took them so long.
I've had the t-amp for a few months now, in place of my treasured Leak Stereo 20, fed by a modified Hafler preamp, and driving a pair of Tannoy HPD385s. Power is supplied by a 12v 1.2A unit from Maplins. How does it sound? After the mandatory burn in the first thing that struck me was the clarity and level of detail being resolved, not analytical, just detailed. Vocals are very clear and cymbals clean.
The soundstage is wide deep and tight. It also goes very loud with 91db speakers. Needless to say I found myself trawling through my record collection and making new discoveries. Treble and bass are a bit rolled off, but after replacing the input capacitors the bass has now gained weight. Not to mention no hum and instant on - I like this! It's enjoyable and undemanding.
Is it replacing the Leak? Sadly no. There's a slightly artificial quality to the t-amp which I couldn't shake off and which I'd put down to the digital source I was using. Changing to my turntable revealed it was the t-amp making vinyl sound like CD! In fact with piano music the effect can be really quite unpleasant. I think if you're used to the digital sound you may well tune this out.
For anyone needing a simple solid state amp it's a no brainer, and the small size makes it ideal for projects (active speakers anyone?). I've ended up using mine with my iRiver (the purpose it was intended for)!
Clive - E-mail: Clive_r2001 (at) yahoo.co.uk

I got a T-AMP from ebay UK for £34.77 inc. P&P, it duly arrived about 9 days ago from San Francisco [very fast delivery!] My goodness it's small! It looks more like a £1.99p air purifier you would get from Wilkinson's! [cheapo dime store].
Actually the case is fairly well made and all the parts fit together okay, the spring-loaded speaker inputs are poor though, it came with a ridiculously short input lead and that's it!
I went and bought 8 AA batteries which filled up half the amps inner space, That's how small it is! Anyway because I had no phono-to-1/8" jack adaptor I hooked it up to my Soundblaster soundcard, and Mission 731 speakers [89db allegedly] with some generic so-so OFC cable. I turned the wick up to 10 0'clock and played some tracks through Winamp. My first reaction was how intense and "brassy" thing sounded, not grating nor offensive, it just seemed to have a "chrome-plated" sound, I noticed a presence and clarity on Nat King Cole's' voice I had never heard before, a glass-clear silkiness with gorgeous rich-sounding strings, drums on some U2 tracks sounded very much like wood hitting skin, the snares gave out a papery ring if you know what I mean, and yet some tracks sounded bloody awful!
The bass was pretty dwindling...but all-in-all it was a good experience really, it was certainly different from my aged Cambridge amp which by comparison now seems very muffled and thin. When I turned the volume up some more it quickly ran out of steam which I put down to the cheapo AA batteries. I think they have a lot to answer for! I got a 12v 2.2Ah battery from Maplin, hooked that up and immediately I was able to turn the volume up some more without any harsh clipping. And there's bass too! I want to do some modding but before that I want to try an external mod by placing capacitor across the battery terminals, which I believe will give it a more welly: I've been offered a big 10,000uf 24v electrolyte to put across the battery terminals, and would gratefully welcome any advice on this before I go ahead. The T-AMP is definitely getting better by the day, it seems to have rounded-off all the hardness, it's very listenable and musical, so all I can say is try one coz' if it sounds this good in it's "raw" state how will it sound when it's properly set up with a better source? I've just ordered another T-AMP for backup.
Update: capacitor fitted, now I have more bass and richness, this amp is phenomenal, it can only get better. I'm not asking you to throw your expensive old amplifiers in the bin, just your preconceptions.
Eric - E-mail: Runcorn4 (at) hotmail.com

Hi, I love your site. Hence, this review for your t-amp section. The TNT-review of the SI T-amp re-fueled my interest in hifi, and got my into DIY-audio to boot! I found the amp on eBay with the purpose to have a nice small amp for the iPod in the kitchen. I hooked it up to a 3-5A RPS and my pair of vintage B&O s45-2. While listening during cooking I got more and more amazed! Even with mp3 the music completely opened up.
I heard melody lines and instruments I had not noticed before. As a result I wanted to build the Big Fun Box, I wanted to hear more. When I found the Fostex FE 206e I decided to notch up with the cabinet, and I build the Singular transmission line design of Bert Doppenberg and Onur Ilkorur, modifying the drivers with wooden phase plugs on the way. This provided an new level of experiencing my cd's!
As a next step I modified the T-amp, putting it in a new box (an old treasure-chest, to become my Treasure-Amp :), added a 7Ah SLA battery, bridged with 1uF, and a decent Alps pot. It was 15 years since I soldered stuff, I hadn't so much fun in ages. So, thank you TNT, for your contagious enthusiasm. I published a more detailed report on my modifications on Bert's forum
Alexander - E-mail: a.vandenbosch (at) solcon.nl

I recently installed a T-amp in my system, replacing a Pass Labs Aleph-5 PA, but keeping the rest (Pass x-1 Preamp, Sony SACD-1 and Yamaha NS1000M speakers). The effect was very interesting, in some way similar to switching to electrostatic speakers from the Yamahas.
Stereo image improved and more detailed. Complex sounds more clearly defined. High-frequency low-level sounds easily able to be distinguished. Deep bass OK, but transients weak (it is only 6 watts!).
The sound stage was very wide. The amplifier, on batteries, was absolutely silent. In terms of value for money the amplifier is outstanding. In terms of quality of sound, the story is similar. Obviously the power limit is an issue, and I have not yet tried it with my electrostatics. I am very keen to build a couple of monoblocks on the 50 watt versions, but that is a winter hobby.
Overall, my Pass amp is going on to eBay as I return to the fun side of HiFi and start building again, based on these excellent TriPath chips.
George - E-mail: george (at) oaklodgeconsulting.co.uk

I reboxed the SI in a second-hand steel instrument case and modified the input circuit as recommended by Michael Mardis (www.michael.mardis.com/sonic/start.html). This is a worthwhile and cheap mod providing more precise mid and treble. Additionally, I removed the pot and installed a power switch. Control is now provided by a WAD PRE II valve preamp (www.worldaudiodesign.com).
It's pointless trying to quantify the improvement in my listening experience. I can tell you I now hear more. More voices, instruments and emotion. The soundstage is wider and deeper and the treble seems so live you could almost reach out and grab a cymbal. I suspect less obvious improvements to the mid makes a large contribution. Despite what you may hear regarding the problems using switch mode PSU's with the SI, I am using a Power Pak II from Russ Andrews (www.russandrews.co.uk). This is a modified SM PSU and sounds very good.
How does the modified SI compare to my previous valve power amp, a WAD 6550? No contest, the SI walks all over 6550 in every department but bass and I'm working on that. The SI is now a permanent fixture in my system until I build a more powerful Tripath chipped amp from Autocostruire (www.autocostruire.com).
My audio setup consists of the following: Linn Sondek turntable, Marantz CD63SE CD player, computer with Terratec DMX 6Fire 24-96 soundcard, WAD PRE II preamp, WAD PHONO II, WAD PSU II, modified SI power amp and my own design vented cabinets containing Audax HT080G0 full ranger drivers.
Adrian - E-mail: adrianparker (at) hotmail.com

What to say... it's true. Now listening to Diana Krall's "The look of love" and the quality of this little monster is clear.. but let's try and be objective: my -limited- comparison is between my usual chain: cd player Densen B-400+, pre Exposure 7 powered by two Exposure 7 supplies and an Exposure 4 as amplifier, the speakers being a couple of Magneplanar SMG (whose sensitivity isn't high at all, 86 dB, 4 ohm load); ah, cables: signal and interconnects are VanDenHul D102 MKIII, power cables are Exposure's ones.
Versus: the same chain, exchanging my beloved Exposures with T-amp powered by an Alpha AC-DC converter whose output is 13.8 volts and 7 amperes...(60 euros).
So now the meat: surely a "non-inferiority" result, maybe a slightly better precision and separation between instruments; voices are well, very well, represented; so is the stage, well in the end...until now I haven't found definite weaknesses in this T-amp...
What about power? maybe I'm not the loudest listener but I should quit the room in case I rotated the potentiometer more than a THIRD..sic!
Synthesis: stunning, if a bit expensive (35 bucks..!).
Sandro - E-mail: sandroborrini (at) hotmail.com

This is probably too long and does not qualify as a "true" review but I wanted to share my thoughts on this truly amazing little amp that you introduced me to...
Bought one of these based on the TNT review and hooked it up to a pair of DIY BFB's with Fostex FE206 drivers and a surplus Rotel CDP. I started with rechargeable batteries and then switched to a 13.8v wall wart. I was shocked by what I heard. I was unsure if the sound was truly as good as I thought or was colored by the ridiculously low price tag. It really did not matter because I was enjoying what I was hearing. The amp really brought out the qualities that I have enjoyed in my BFB's. Not sure of all the correct "audiophile" terms but there was a wide and deep soudstage, there was clarity in the sound and separation in the instruments. What was lacking was the low end bass.
This is partly a function of the speakers, but what I can say is that the low end bass that was there was fast and tight. I really had a hard time walking away from the setup and ended up listening to CD after CD. In the back of my mind I kept thinking that I must have been prejudiced by the price tag and my low expectations. I decided to swap my NAD 3020 receiver back into the setup (my previous low cost wonder). Well, the 3020 did not seem to be the low cost wonder it once was. The T-Amp has done something for this setup system that the NAD didn't do...it has kept me interested and kept me listening. Once again, I keep wondering if I keep listening because I am simply just amazed by this thing (the price, size, etc.). I decided to do something that I have regretted since I did it.
I decided to go back to my (mid level) main system for a listen. Even after running through some of my favorite vinyl and CD's on my main system (VPI 19jr., Rega Planet, Audire Preamp, Conrad Johnson Amp, Dynaudio Audience 42's and REL Strata III), I was back listening to the T-Amp and BFB's. At this point I have resigned myself to the fact that my main system still sounds much better but I choose to listen to the $200 T-Amp and BFB setup because of the novelty of such a good system for the price. This helps me keep my sanity and sleep better at night.
Keep up the great work,
P.S. I have purchased 3 of these T-amps now. I replaced the first because the speaker clips broke and I wanted to use better interconnects. I botched the first "mod" to the replacement and ended up purchasing another. What I had planned to do is mount the thing in a nice case, add some Cardas RCA's, Vampire binding posts, a better quality pot and a 12v SLA battery. If I keep it up maybe I can drive the total cost of the system up to a point closer to how it sounds...that may take ruining another 30 amps though!!!
Brooks - E-mail: bharris (at) capro.com

It's been several months since I gave my initial impressions on the tripath amp. Initially I preferred the more powerful Teac to the SI; however, as the amps broke in I noticed that while the SI didn't have the Teac's heft in the bass, it had a better, more dynamic overall presentation, and far lusher mids and highs. In addition, as the amp opened up more I found that a preamp was no longer needed. (I also found that SI's own 12v power supply gave fatter bass, sweeter highs, and a deeper soundstage than either batteries or the 13.5v power supply I initially used from Part Express.)
With a phono stage from Channel Islands on the way and some mint Klipsch LaScalas due to replace my less efficient kg4's, I can honestly say that the my SET is no longer needed. While I still think that SETs create a certain magic that is unique to tubes, I find more and more that when it comes to simply sitting back and enjoying music, I prefer the SI.
Scott - E-mail: scotbuck (at) sbcglobal.net

I wanted to play music on my patio next to the swimming pool and stumbled across the S.I. T-Amp and Yamaha NSAW350 outdoor speakers. The speakers are 6 ohm impedance and 87 dB sensitivity and a pair cost a $100 delivered.
I installed the T-Amp circuit board and original pots in a small Hammond project box with heavier gauge wiring, speaker binding posts, RCA connectors and a toggle power switch. I used Anderson Power Poles (www.andersonpower.com) chassis mounted for the DC supply. I used this connector since I have them installed in my amateur radio equipment PSUs and batteries.
During my 50 hours burn in period (at 13.8V, Lucio) I made A/B comparison speaker tests in my music room and have to agree with Lucio's review (although I understand Eric W's position). The T-Amp is an amazing little amplifier. It will be under used for background music for the occasional pool party, but it will go to anti-social volume levels and still sound excellent.
What I need is at least 20 ft feet of white jacketed phono cables with RCA connectors since my covered patio on the back of the house is white. Anybody have any supplier ideas?
Dave - E-mail: delear (at) charter.net

I love this amp!!! For once, I do not feel taken by the hype that seems to pervade the audiophile community. I'd trade all of my DIY cables, connecters, stands, tweaks, and triflings upon which I wasted countless sums of money for this one slice of sonic delicacy.
Without a doubt, I got 100% of what I paid for, and yes, I would pay a lot more for the sound coming from my T-amp. But, I don't have to! I live for cheap good sounding equipment, and the T-amp makes my mid-fi setup sound better than I imagined it ever could. Buy two and keep one for backup!
First, I'd like to say a few words about my setup. I feel this is necessary because I believe it is fundamental to my success with the T-amp. I'm running the T-amp as a power amp at full volume with the 12v power adapter from sonic impact. The T-amp plays into my trusty B&W DM302s (91dB sensitivity). Most importantly, the T-amp only supplies the power for 100hz and upwards. Bass is provided by my DIY Shiva sub, crossed over electronically with a Marchand crossover. This allows me to play at significantly louder volumes without having to worry about clipping. Burn in so far is about 25 hours.
I'm not going to throw in a lot of fancy jargon like "timbre", because frankly, I'm not sure I know what it means, and I question whether others do. Quite simply, everything sounds better. Drums sound more like drums and pianos sound more like pianos. Feel free to be disgusted by my oversimplification. In my opinion, the T-amp's best quality is not what it sounds like, but what it does not sound like. Gone is the feeling that I got from my well worn NAD 3020 that there was too much sound information coming from my speakers. With the T-amp, I can hear spaces between instruments. This amp is dead-quiet where it needs to be and crisp and lively everywhere else.
I don't know how this amp sounds compared to a $15,000 amp, and frankly, I don't care. I LOVE the sound that comes from this little hunk of plastic, and I'm sticking with it. In fact, I'm scrapping the plans I had for a major speaker upgrade and investing instead in MORE MUSIC so I can play it on my new T-amp.
Andrew - E-mail: hartleyerisalaw (at) msn.com

I was very interested in the t-amp since the first review, so I immediately ordered one (at) thinkgeek, who were very fast, indeed (since the point they got the amp because it was out of stock, of course)...
First I plugged in batteries just to get an opinion, used a simple 3.5mm Stereo2RCA hugged my preamp to it and made a connection through some cat8 networking cable (works, but is not _the thing_). What I heard immediately was a very wide soundstage and a very, very detailled sound leading me to think "what is THAT? So much Music from this little plastic case?". On the negative side it was all new an had (according to Lucio) break in for a while.
What went partially away after some 20-50 hours, was an overall hardness coming from a too thin bass - for my opinion -if compared to my japanese/chinese 8*kt88 valve amp. What I was missing, too, was any depth.
Sound was very clear, but not deep at all, so I waited for a while to search for a suitable power supply.
I finally got my 13.8V 6A regulated (not switched) power supply and hooked it up to see what comes next...
The sound got bigger, slightly warmer, better in any way and (according to the warmth) the hardness slipped away even more. But still no "I would put my valve amp away for that!"...
So I remembered the bad connectors and decided to open the case and solder medium serious connectors to the amp. Again some hardness went away (Now being flying around having no case at all) and the little amp (still using its original volume control) got even better. But: Still no chance to beat my valve in any way, except clearness.
So maybe after a few more (and more thought through) modifications it will get nearer, but actually it's just a very good amp for the money spent, not the technical breakthrough and Monster killing best amp of the world - but who would expect this :-)
I got much fun with the little one, and maybe after a new round of tweaking then comes a followup...
Besides I am driving electrostatic speakers and not high sensitivity full range speakers (which I will try!), so the lack of bass may come from this...
Michael - E-mail: michael.rinus (at) gmx.de

When I spotted the T Amp in the Parts Express catalog, I thought this is a neat little toy, it might work to power some cheap speakers at work and hopefully sound better than the dreadful little boombox we were listening to. No high hopes or great expectations whatsoever.
After doing a web search on the T Amp and reading the very enthusiastic reviews on several audiophile sites, I was hopeful and skeptical at the same time -hopeful that it might sound as good as a decent receiver, skeptical that it could possibly sound as good as claimed on TNT and other sites.
Well, after owning this amp for a week now, all I can say is WOW!!!!! When I connected the T Amp to my PSB Alpha Mini's for the first time and pressed play on my Sony CD Walkman my jaw hit the floor -- I was speechless -- then all I could do was babble like an idiot saying things like "not possible" "$30" "unbelievable" "there's no way" "plastic case, junky spring clips" "amazing sound" "cheap little toy" "soundstage, presence, slam" "not possible." Well, you get the idea.
This thing sounds as good or better than any amp I've heard - period! It's damn near impossible to get what you're hearing to jive with what you're seeing when you look at this thing. I still shake my head in disbelief every time I listen to the T Amp and still occasionally break into babble. UNREAL!
Travis - E-mail: prophecy18 (at) aol.com

I've read Lucio's and Geoff's T-Amp review and got curious about this tiny gimmick and this is my "thank-you" note. I've connected it instead of my SE tubeamp with a simple 12V switching power supply, built plugs to connect the speaker cables and switched it on. WOW! This amp really sings! Exactly, as described in the reviews: Dynamic, Dynamic, Dynamic, Punch(!) and bags of detail! It sounds not like solid-state and not like tube, it's best described as if the music is played through the amps of a big sound-studio. Timing is perfect and the bass comes very fast and "dry". When I connected it to an open-baffle system with a Ciare fullrange-speaker and an Eminence 15" woofer the bass comes so hard that you believe the Rockford-Fosgate-Promotion-Car of 2005 has stopped in front of you - but the T-Amp/Eminence combo sounds much faster and more precise :-)
My wife doesn't like the big open-baffle system so I've put in back in the garage and connected my Loth-X fullrange-speakers. With their 96dB/Wm, 6 Watts of power can go REALLY loud! But in my opinion, the T-Amp sounds best at moderate levels. Next project is to build a kind of "dockingstation" for the T-Amp with a decent powersupply and RCA and Banana connectors. I think I will replace my current tube poweramp (with was good enough to replace a big and expensive Naim Equipment, some time ago) with the T-Amp. It sounds better...
Martin - www.krauhs.net

After reading the 6moons review I got quite excited over the T-amp then after seeing yours I knew I must get one or two...not so easy here in the UK at the time, would have to buy from US and was getting large shipping costs quoted, that is if anybody had any! In the end other things took my mind for a few weeks then your letters got me thinking again. So ordered a couple from Thinkgeek on a Monday and received them on the following Wednesday - only two days to get from US to UK - excellent service. Played around a bit with one using a 1200ma supply with my Rotel RCD-985BX and Spendor BC1 (not the easiest load) and it sounded very good indeed - as did using wav files on my Iriver H140 using Celestion Ditton 15 - but was lacking in ultimate power. I tried using my turntables with it but found the preamps in my integrated amps did not have enough gain.
So onto stage 2. This week in UK Lidl advertised a 'Mobile Energy Station' (http://www.lidl.co.uk/gb/index.nsf/pages/c.o.oow.20050523.p.Mobile_Energy_Station) which is a battery power supply complete with charger for just £14.99 and gave 12v 7ah, this sounded just the job so I bought a couple.
Now to get over the turntable problem. I needed a phono preamp which gave a reasonable gain and didn't cost much cash (this was meant to be a budget excercise). I spotted the Cambridge Audio Azur 540P (http://www.cambridgeaudio.com/summary.php?PID=28&Title=Azur+540P) for just £39.95 at Richer Sounds ( http://ws4.richersounds.com/showproduct.php?cda=showproduct&pid=CAMB-540P-SIL&SID=4a09ba96298b22dec6b0175c5dd57b11 ) this seemed just the ticket as it gives 300mv nominal output for 3.35mv input...so travelled 40 miles to my local Richer Sounds to get one.
Put it altogether last night Lenco GL75 in massive constrained layer plinth (http://members.lycos.co.uk/willbewill/GL75/Complete2a.jpg ) complete with Decca International arm and Shure V15 III, feeding through Cambridge Audio Azur 540P into T-amp powered by Mobile Energy Station (the lead from 'lightersocket' output was perfect) into Mordaunt Short Pageant Series 2 speakers (a classic which sounds very good and reasonable easy to drive) via FFRCs.
All I can say is WOW! Plenty of volume (half way on T-amp gives more than enough for normal listening), incredible detail, phenomenal bass, huge soundstage, drumkits which sound like drumkits, vocals which sound 'in the room' and great PRAT. I was using a Pioneer A400 on this system (not my main one) and whilst it has more power it really sounds quite 'muddy' and 'warm' compared to the T-amp combo. Next stage is to try it with the Spendor BC1s and my other Lenco ( http://members.lycos.co.uk/willbewill/GL75/plintha%20complete.jpg ). I'm also getting really tempted into building a pair of Full Range Speakers based on Singular cabinet and Fostex FE207E.
Malcolm - E-mail: malcolm.coulson (at) ntlworld.com

I couldn't resist the opportunity to tell you a little about my experiences with this amp. My normal amplification is a pair of mono'd Leak Stereo 20s originally built by Peter Bruty and refined by Glenn Croft. My preamp is a Audio Synthesis PAS-02 (stepped resistor model). My main source is Garrard 301 in Maxplank plinth with Rega RB300 (Incognito rewire and Martin Bastin counterweight) and Dynavector DV17D2 mk2. My speakers are Klipsch Forte IIs.
I initially used batteries but quickly changed to a 13.8V Maplin power supply. With this replacing the Leaks I find it plays music, bass is slightly restricted compared to the Leaks, imaging is better especially in depth, detail is on a par, and it is silent in use (no hiss, hum, etc). I prefer the feeling of musical flow that the Leaks provide and I think I'll eventually revert to them because I value that. For now, though, it's fun to play with this little amp. It doesn't take ages to warm up, it takes up no space, it has no pretentions.
I agree with other comments about it turning the amplifier world upside down. Surely there are "serious" hi-fi amp makers looking at the circuitry at present? If not they should be. There must be many ways of making this into a real amplifier with decent power supply, better quality passive components, a nicer box, and the like. I'm sure it doesn't compete with the real high-end amps, but for anything up into the mid-market it's a revolution on sound quality. Longevity? Who knows?
But at the price it's cheaper to buy a new one than repair it. And I hear that Sonic Impact has a "mark 2" in the wings, with more power, and even an "audiophile" version. These could do for amps what the RB300 did for arms up to £1000 a few years ago.
Thanks for a great website.
Peter - E-mail: peter-ward (at) btconnect.com

Stock amp used as an integrated with rechargeable batteries (50+ Hours use) - assessments are made at an absolute level (i.e. regardless of price): Good. High degree of clarity and intelligibility throughout the bandwidth. Identifiable imaging. Good soundstage. A perceived extra half-octave of bass extension.
Bad: the T-amp's clarity is artificial sounding (..note that I do NOT mean that the level of clarity is artificial, rather that the nature of it is artificial). The "sound" of this clarity (and of this amplifier in general) is something you really don't find in anything else but a low 2nd order THD pentode push-pull amp with a VERY low output impedance (..like a massively parallel OTL can provide). I suspect the increase in clarity of this amplifier over other good (class AB) solid-state amps has to do with a lack of, (or much lower), crossover distortion. (..note that this is NOT distortion related to speaker crossovers - google for more information).
The imaging is also artificial in its nature ("pin-point" in nature). Instead of a virtual holographic image (of a singer, musical instrument, etc.), you are presented with a very "tight" sound locus. This is a common phenomenon of an overdamped output from the speakers (resulting from a very low amplifier output impedance). To an extent, this results in greater perceived clarity - especially in most speaker's bass response. What suffers though is tonality and decay - especially decay (though they are inter-related). The soundstage is also artificial in sound (in some respects). The artificiality in this instance is common to push-pull "like" amplifiers with regard to width. It isn't that you can't have a wide soundstage reproduced, its that a push-pull amp ALWAYS provides an overly wide soundstage regardless of the recording.
(Note however that width differences in recordings are presented, just not to a level that very good single-ended output does.) On the other hand - width AND depth is reproduced a bit better by this amp because of the clarity of bass in the infrasonic region. Simply put, you can hear low freq. hall-sound better because of the greater control this amplifier exhibits over speakers (..provided your speaker has audible output below 25Hz).
Upper freq. room/hall decay in the presence region, (sometimes referred to as atmosphere), is all but missing - again a common occurrence for low output impedance amplifiers. Bass is curtailed in response below 100Hz due to a known manufacturing defect (.. an input capacitor that does NOT meet Tripath's specification). This is an SPL issue and may or may not be negative in your system, (..because bass response in-room can very greatly). (Its also easily remedied..) Despite this however, many speakers will sound as if they gained at least another half-octave of extension because of the greater control the amplifier has over the speaker. (Additionally, bass "slam" is increased as a result). The price to pay for this perceived extension and slam is tonality and decay. As a result midbass to lower midrange can sometimes become a bit "one-note'ish". (Note though that IS dependent on the speaker's driver(s) reproducing this frequency range.) Overheating on the new amps can be a problem. After a couple of hours of use my amplifier, (a more recently manufactured one), cut-out on me. After a brief period of non-use (aprox. 5 minutes), the amp was ready to go again. Like the capacitor manufacturing defect - this new defect is from a lack of heat sinking for the chip. And again, like the cap. problem, this can be easily remedied with a small heatsink.
Conclusion: the above may sound like I didn't like the amp, but nothing could be further from the truth. Instead the comments above were made at an absolute level - to let you know the real deficiencies of the amp (..beyond the obvious restriction in power output). In fact I have a feeling that most people will find that the stock amp is overall preferable to their own amp - its that good.
Modification: I haven't done any modification (yet) to mine, but I have a feeling that FAR better sound can be achieved. In particular the input capacitor is IMO the weakest link in the sound, not only because of the "rolled-off" bass response, but also because of the quality of the capacitor. The problem here though is getting the right capacitor and connecting it properly. A high quality film cap (2.0 to 2.2 uf) bypassed with a Teflon cap (.1 uf) should do wonders for the sound. Connection is another matter - I'm told that connecting such a large capacitor is quite difficult. Furthermore, shielding the the capacitor leads becomes essential due to the large quantity of emf produced by the digital chip.
Scott - E-mail not supplied

I am not a great specialist in reviewing HIFI. I have just my ears. I was looking for a new CD player to change mine which was 15 years old and during my search on the internet I discovered some forum (and especially your web site) on a new little amp that would cost nothing and should do a great sound. It was not very easy to find one but the internet is big and finally a ridiculous little box came to my house. It was not very easy to connect my loudspeakers and my new Jolida JD100. I was immediatly very suprised by excellence of the sound. It will be difficult for me to do such a good review as you gave done but I must admit I agree 100% on what I have read on TNT.
I had - until now - a Mission Cyrus 2+PSX. 10 years ago I had listened to dozens of aps before choosing this one. This little gem outperforms without no problem my old amp. The most surprising fact was to discover that my old amp did hide so many microinformations. The space between the instruments was much better and much more precise. I was also very surprised that my children (10 years old) who are not crazy about classical music started to ask me to play some CD now!! This is good news to me. They never asked me for a classical music CD before...
I convinced my brother who is living in the US to buy one and like me he was completely surprised by the quality of this marvel. After the pleasure of such a discovery I decide myself to change the connections to improve the sound. So I came back to the DIY forum and I discovered Michael Mardis web site. So I decide to follow him and to make the small change that he did propose on the inputs. I also bought a strong powersupply (12V 6A), I did the modification and I must admit that my already excellent Sonic T-Amp became even better. More soundstage, more bass, more precision.
Since I have this new little amp, I have bought dozen of news CD. It is just a pleasure to listen to music again.
Frédéric - E-mail: flaude (at) mac.com

The Sonic Impact T-Amp is very light in weight and difficult to connect into a 'proper' hi-fi system. You said so in your review of it. When powered from a 12 volt [open circuit voltage is 13.5] golf trolley battery, it sounds amazing. My wife and I simply laughed, astonished, at the sound. Whatever CD I played sounded great, country, blues, piano etc. etc. This amplifier presents a serious problem for the hi-fi industry, why can they charge us ?5K+++++ when for around €30 [less than €100 including battery] we can get a lot [most of???] of the ?5K+++++ sound quality.
It is not very often that the feeling hits you that it is not possible to get any better sound quality, that feeling came over me as I listened to the music. Of course it is possible to get better sound but it is hard to imagine how. The sound was that good.
But it is worth all the trouble that one has to go through to connect it up. I did not try it with a mains adaptor but as I said, the performance when powered by a lead acid battery is incredible.
Which brings me to the question of the moment, what if Sonic Impact were to fit the amplifier module into a 'proper' aluminium case with a good pair of input sockets, decent quality speaker posts and a high quality volume pot & use an external power supply. A top class single input integrated amplifier for € 150 or so. Maybe if they did so at the start, the world would not have come to realise what a gem we have. But it is not too late for an audiophile version to be produced. I would buy one, no make that two or three [Christmas and birthday presents], in a heartbeat. What better gift than the gift of music. In short the Sonic Impact T-Amp is an amazing product and one that ordinary mortals can afford.
Thank you for giving us such a wonderful and honest website, one that is not afraid of taking risks. Thank you for letting me know about the Sonic Impact T-Amp.
Tom - E-mail: tomfox (at) bennettconstruction.ie

This little thing really sings. If you already have a very good system, keep apart your prejutgements and give it a chance, you just lose a bit of time and a ridiculous amount of money.
O.K. Sharp your ears and blank your mind, as I did. The first I feel when press play was a shock, this little device do some things in the same way that my Unison Research S6 in terms of tone and timbre, but do all the others things far better.
The Focus and transparency gives you a deep and very wide soundstage where the musicians flow and swing. That's for jazz; I put the Kubelik's Mahler 2nd in LP to hear what the hell is happening. Controlled orchestral planes, really good dinamycs for the power it delivers, and a real soundstage. The timbre and tone remain the same as the Unison. I put the Celibidache's Pathetique, a good live recording and one of my favorite Tchaikovsky's 6th. The level of silence and microdynamic contrast, keeping the music's harmonic richness was breathtaking.
If your room is 15-20 m2 and your speakers' impedance remains 1-1.5 below the nominal you'll get a tight, well defined and fast bass in highest league, but with 6 watts or so. I still don't play any audiophile recording, I don't need it.
The Sonic Impact T-amp "really" sings if you feed it with good juice and a superb system.
System: Audio Analogue Maestro CD 24/192; Pro-ject 2.9 classic, Clearaudio Aurum Beta-s, extreme phono none-frlt mat + Skin; Jean Marie Reynaud Trenté loudspeakers; Vibex Reference Power Filter; Lovan furniture; Gutwire Notepad (atop the cd drive mechanism); Acoustic System Rsonator; Ers paper.
Carlos - E-mail: guarnieri129 (at) msn.com

I was fascinated by your review of the Sonic Impact t-amp. I've since purchased the SI as well as the Teac t-amps (since I'm using 94dB-sensitive Klipsch kg4 speakers, I prefer the extra clean power of the Teac). What I discovered is that if you *really* want a sound-for-the-money shock, try one of these t-amps with their volume controls wide open in conjunction with a preamp from http://www.phonopreamps.com/ (I purchased the one which had a phono stage, three passive line stages, and a stepped volume control for about USD75 [that's the T-Preamp we reviewed]).
I was *amazed* by how much the performance of the t-amps improved when using the preamp (not to mention the joy of hearing my vinyl recordings through the t-amps). The combination makes me question whether I still want to keep my SET amp! They really do sound that good!
Take care and thanks for the original review,
Scott - E-mail: scotbuck (at) sbcglobal.net.

The optimist in us believes that the money-for-value index can routinely be beaten, and we therefore too readily repress memories of the last time we thought we could get more than what we were prepared to pay for – only to be rudely brought back to reality after the purchase. The world of hi-fi offers additional complexities: while at the low end you generally do get what you pay for and no more, at the higher end the law of diminishing return seems to rear its ugly head. Introduce purely subjective variables such as the listener's ear and room acoustics, the review of a piece of equipment as a function of its price becomes a real challenge.
So when I read TNT's review of the Sonic T-Amp, I thought here is an opportunity to find a reference point from which to find a fix on the confusing audiophile landscape of "real stereo" that I have just recently returned to after a long absence.

I received my T-Amp after having placed an order quite some time ago (it is often back-ordered – a fact that was perversely reassuring evidence of its increasing popularity). Powered with a cheap Radio Shack power supply, the T-Amp took the place of my Decware Zen Amp in a system using a Mapletree Audio Design Ultra 4A SE pre-amp and high efficiency rear-loaded horn speakers with Fostex FE206E full range drivers—a system I have been very happy with.

And how did the introduction of the T-amp into the system sound? First I tried to forget its ridiculously low price – a next to impossible task. Then I pretended it was a $1,000.00 amp... a $2,000.00 amp...O.K. that works. So, the sound? Well, I didn't miss the Zen amp as far as its overall presentation is concerned. And where the T-Amp really shone was in its soundstage. Instruments and voices were fixed unwaveringly in a sound stage that is wider than I have ever heard in my system.

Does the T-Amp provide me with the point of reference I was looking for? No, but only because my world has now been turned upside down. How does one approach a product that turns on its head the tried and true consumer aphorism I started with and gives you so much more for your money than you had dreamed possible at that price? If you can figure this industry out, let me know. Oh yes, I ordered another one before the price goes up.
Oliver - E-mail: oliverbremer (at) rogers.com

You may want to read what Carlo Morsiani, designer and manufacturer of high-end turntables and arms, has to say about the T-Amp...