The TNT-Convertus: a minimalist DAC

Product: TNT Convertus
Company: not for sale, TNT-Audio free DIY design
Approx. cost: 200$/Euro (just components)
Reviewer: Lucio Cadeddu

The almighty TNT Convertus

Last Winter I had the possibility to listen to the first prototype of what would have become the first official TNT DIY DAC design. It was mostly a standard unit, nothing particularly revolutionary or fancy...but it sounded damn good, proving once again that when it comes to DIY design, our Giorgio Pozzoli is second to none :-)
Few months later Giorgio sent me an E-mail saying he was trying a completely new (and pretty revolutionary) approach, following the ideas of Mr. Kusunoki, that is, zero-oversampling and no digital filtering.
WOW, I thought, this is going to be exciting!

This Summer the TNT Convertus was ready to rock and Giorgio decided to visit Sardinia (the "far-away from anywhere" place where I live...)....I couldn't miss the possibility to test the new TNT baby inside my reference system! And here are the results...

Convert...yourself!!!

The TNT Convertus is something very different from what you may have seen/heard till now. The zero-oversampling - no digital filtering + over-mega-sized power supply DIY DAC is something quite special.
Its sound is sweet as a good gelato, harmonically very rich, especially in the highs, clean and pure like a mountain spring in the Italian Alps.
If you ever had the possibility to listen to a top-end analogue playing system you can easily get the picture: the TNT Convertus sounds so close to analogue that makes you wonder whether you're listening to a digital rig or not.
Dynamically vivid, precise and still very naturally involving. No, it is not a turntable...but it gets very close (provided a top end CD transport is used) :-)
Considering the cost - 200$/Euro for parts - the TNT Convertus sonic performance is stunning since it sounds with the same quality of a 1000 $/Euro commercial GOOD DAC converter...no, it will not replace your Wadia, but it dares to offer something which is quite close to it (in overall quality) with a added strong personality. Not bad, uh?
It is not perfect, though, since we prefer to leave "miracles" to Someone Else up there.
So the TNT Convertus has a light first octave, that is to say, the ultra-deep bass notes (organ etc.) lack weight and energy. Not so the rest of the bass range, punchy yet with a touch of velvet.
Low level listening unveils another plus: while many digital players become unbearable and thin at low levels, the Convertus simply shines with a rich harmonic sound texture that makes you turn the volume up again to concentrate on Music.
This uncommon feature is certainly due to the mega-oversized power supply (have a look at the 3 HUGE toroidals in the picture above!), to the top-class passive components (such as paper-in-oil caps, Wima stuff etc.) and, last but not least, to the minimalist approach in the circuit. The sounds simply comes out of the DAC chips and goes directly into your amplifiers, no oversampling, no filtering.
The TNT Convertus is also able to create a realistic soundstage, large and mostly DEEP, unbelievably DEEP, with the virtual "rear wall" very far away from the speakers' horizontal plane...
Not only, the stage is precisely sculpted and extremely well-focused, something just top-end DACs are able to create.

Complaints

Being a pure die-hard DIY design, there's nothing I can say about the construction and manufacturing quality, but I can't help but mention the meticulous air wiring Giorgio has used for this unit. Yes, Virginia, NO PCB's, just plain old air-wiring. And while this is common practice in good ol' days tube amps, do that with digital signals....and you're going to experiment TROUBLES, unless you're a master with the soldering gun :-)
This aspect, that certainly gives "something more" in sound quality, is also one of my major complaints: many readers write complaining because there's no PCB available...well, guys, this is the TNT Convertus, either take it or leave it! OK, I admit, a PCB scheme would have been useful, though....
From a sonic point of view I've really nothing to say, except the already noted lack of weight in the first octave (let's say...below 40 Hertz)

Some advice

DO NOT TRY to modify the original design. The TNT Convertus sounds so good because it is a fine and ear-proven mixture of good ideas, superb components, excellent power supply and layout, born after so many trials and errors that it would be difficult to do better and very easy to do worse. I can't guarantee you will get the above described sonic performance if you don't follow the design carefully!

Conclusion

I know what you are thinking....it's too easy to write a positive review of something we are offering (for free) as one of our DIY designs. And you're wrong! The last thing I want is to propose a design with the name TNT on it when I'm not totally and completely satisfied with its sound. And NEVER forget we don't sell anything here! We are just offering (for free) a very interesting project for an unusual DAC that, with 200$/Euro, can bring your system close to hi-end performance.

Of course, it is not the best sounding DAC around, it is difficult to build and we do nothing to make things easier...BUT!!!! It's free for all and it sounds damn good.
So... happy DIYing to everyone! I hope you enjoy your TNT Convertus as much as I've enjoyed it!

Below you find the articles on the Convertus (theory, schemes, components list etc.):

[Part 1] | [Part 2] | [Part 3] | [Part 4]

Copyright 2000 Lucio Cadeddu - http://www.tnt-audio.com