TotalDAC USB Gigafilter | Review

Digital is dicey

Looking at the totalDAC USB Gigafilter, you ask questions. Digital is supposed to be straightforward: ones and zeroes coded as “Hi” and “Lo” voltage signals, all marching forward in a straight line like kindergarteners to the bathroom. That’s pretty much it, right?

The complexities of vinyl playback, in contrast, are easy to understand. Move that cartridge in any direction, and you affect the way the tip of the stylus hits the grooves … Which in turn affects the sound. Makes sense, right?

For a long time, I wanted to be (and was …) of the ilk that believed that digital playback should be a walk in the park. All we have to do is “read” a set of voltage pulses coming at us in a certain order, and voila! Outcomes perfect music. How hard can it be to differentiate between a “Lo” voltage and a “Hi” voltage?

Well, as with all else in perfectionist high-end audio, the devil resides in the details. Once computer audio started to become a thing (early adopter here), I began to read about how swapping out USB cables makes an audible difference. Hmm… Oh, and the effects of galvanic isolation between computer and DAC, and synchronous vs. asynchronous streaming protocols. Not to mention re-clocking, differences in DAC chips, yada, yada, yada. In the words of one digital maven, “everything matters.”

Digital is really analog

When we get into the nuts and bolts of digital transfer, we begin to understand why it’s such a bugaboo. If anything, I’m finding that one can go just as far down the rabbit hole with digital playback as with vinyl.

Why? Well, getting right down to it, digital is really just another form of analog. Remember those ones and zeros, which are encoded as voltage pulses? Last I checked, voltage is an analog signal and must be regarded as such. It’s susceptible to degradation, noise, timing issues, and the like. In other words, what starts out at the source most likely won’t be exactly what ends up at the finish line. It’s like playing an old fashioned game of telephone between the digital source and the receiver.

totaldac to the rescue

To achieve the most accurate and best-sounding results, the goal should be to keep the digital bitstream as pristine as possible between the transmitter (your computer or transport) and the receiver (DAC). Even more important is preserving the integrity of the rising or falling edge of the pulse, as that’s where we differentiate between the “Hi” or “Lo” signal in the time domain. Of course, what goes on at the DAC and beyond is a totally different ball of wax.

It’s this idea of achieving a “perfect” bitstream that totaldac’s USB Gigafilter attempts to address. The device itself looks deceptively uncomplicated. It’s a USB cable with a metal box in the middle, which presumably houses the “guts” of the filtering apparatus.

I asked totaldacs’s Vincent Brient for a basic overview of the Gigafilter and what it does. According to Vincent, the device achieves three goals: 1) galvanic isolation between computer and DAC, 2) re-synchronization of the digital bitstream, and finally, 3) extensive filtering of said signal. That’s it, and all achieved within a single “black box.” Thinking back to the idea of the digital signal really masquerading in the analog domain, such an approach makes a lot of sense. Keep it clean and lean, and all will be well.

Does it really work?

My setup and protocol for testing the totaldac Gigafilter was simple. Using an otherwise constant system setup (Mac Mini to Bricasti M12 Platinum Source Controller/DAC (review forthcoming), directly feeding a Vitus Audio RS101 amplifier (review here), which in turn powered my ATC SCM100 SL passive monitor speakers), I spent a lot of time with the Gigafilter inserted between the computer and DAC, and then I removed it.

My first observation (and a quite general one at that…) is that the system sounded very good with the Gigafilter installed. This observation I noticed right off the bat, and it remained sustained throughout. In short, the system just seemed to sound more “naturally effusive”, whatever that means. I had the impression that the music sounded less concocted, that is, reproduced by a mere collection of electronic gear. Whatever the Gigafilter was or wasn’t doing, it most certainly wasn’t hurting anything.

More importantly, though, is whether these “improvements” would remain once the Gigafilter was removed from the chain and replaced by a good quality audiophile USB cable.

The envelope, please

Upon replacing the Gigafilter with my trusty KingRex bifurcated USB cable, I honestly didn’t hear much of an audible difference at first. Benchmarks such as “detail retrieval” and “perception of soundstage” seemed to be precisely the same. However, as with most things audio, it’s the small details that eventually bubble upward.

Without the Gigafilter in the mix, I began noticing that well-recorded piano could take on a subtle aggressiveness in the upper registers that hadn’t been there before. It’s as if the piano suddenly seemed a bit more “forward” sounding from a tonal perspective, with more emphatic leading edge attack. I believe a good way to describe what I am hearing would be to say that the sound is a bit more “forced” with the Gigafilter absent. Of course, evaluations often come down to what a particular listener happens to prefer. Some folks want a mellower, more flowing and laid back overall presentation, while others might yearn for a bit more “excitement”. Those who prefer the mellow side of things will probably benefit from auditioning totaldac’s Gigafilter. What it lent to the musical presentation was a sense of peace and calm that pulls the listener into an organic, and wholly engrossing aural experience — as it probably should be.

One final question

There’s no doubt that the Bricasti M12 I have been using is at the very bleeding edge of high-end digital playback, both in terms of applied technology and attention to tiny sonic details. Jiminy-crickets, the thing costs 20-grand!

This observation, in turn, begs the question: is the Bricasti so well-appointed that it really doesn’t benefit much, if at all, from the “services” provided by the totaldac Gigafilter?

I decided to therefore try out the Gigafilter with another very good, but much less expensive ($2000) DAC I happen to have on hand: the pro audio Crane Song Solaris. The Solaris’ hallmark traits (by itself) include an honest, clean tonality; spot-on timing; and a precise, yet expansive soundstage. The Bricasti M12 offers these characteristics as well, but with that last push toward overall refinement. Would the Gigafilter lift the more humble Solaris up into Bricasti territory?

Long story short, the Gigafilter pretty much took all of the strengths of the Crane Song DAC and extended them. I heard greater clarity, coupled with a significantly improved texture of harmonics. Even if the soundstage didn’t exactly expand in every direction, I seemed to hear better delineation among instruments, as if there was more air between them.

TotalDAC USB Gigafilter

What I ended up concluding is that the totaldac Gigafilter most definitely changes the way a given DAC sounds, with the degree of “change” tending to be somewhat DAC-dependent. More to the point, the Gigafilter can be an effective tool for taming some of the harsh “nasties” that might still be evident in digital playback. It does this by “smoothing out”/”organically filling-in” the sound by revealing much needed harmonic texture and meatiness, but without editorializing in other ways. Keep in mind, however, that your mileage may vary, so try to have a listen before committing.

Cost: 1750 euro (with VAT) or 1600 euro (outside of Europe; no VAT), factory direct with 14-day trial period.

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