Currently, there is only one tried-and-true way to completely eliminate noise from a system—eliminate the signal, because without a signal, there is no noise. Obviously this solution won’t work in the real world, where the whole point is to have a signal. The next best thing to no noise is a signal-to-noise ratio greater than 100dB. The LIO does just that with a >100dB published S/N figure. But internal signal-to-noise is only part of the story; a component needs a quiet, well-isolated power supply, as well. With its ultracapacitor, the LIO has pushed power supply design to the outer limits.
One of the tests I usually run with new gear is something I call my “high AC line noise test.” It involves plugging in a Pioneer LaserDisc player and turning it on. This particular player’s power supply dumps a whole lot of noise into the AC line, which I can hear via my Noise Sniffer AC noise-detection device. I then listen to the component under review with the LD player plugged in, and again with it unplugged from the AC line. With some components I can hear the degradation introduced by a noisy AC line in the form of audible hum levels and spurious noise, while with others no audible differences are apparent. The LIO proved to be completely insensitive to AC power vagaries.
My new house has terrible power—usually running at between 122 and 125 volts with a high level of line noise. To counteract that noise, all my components have some kind of AC power filtration between them and the wall. In my nearfield system, I use a PS Audio Quintet (now replaced by the Dectet) to filter the AC power. I tried the LIO connected through the Quintet and then plugged directly into a wall outlet—once more I could hear no audible differences. If your power is flakey, the LIO is an effective way to lower the effects of AC vagaries to such an extent that, regardless of time of day or season, your system will have the same low level of externally induced noise.
I used a number of different speakers with the LIO in my nearfield setup, including the Audience 1+1, ATC SC-7II, Role Audio Kayak, and Aerial Acoustics 5B. The LIO amplifier had adequate juice to drive all of them without issues. Also, with even the highest-sensitivity speaker, I heard no hiss, hum, or extraneous noise with my ear practically resting on the tweeters.
I was impressed by the LIO’s overall level of finesse and transparency. The Autoformer volume control delivered accurate and repeatable levels with no readily apparent colorations whatsoever. And while some audiophiles will feel the need to add tubes via the stepped-resistor volume control coupled with the tube linestage module, I found the sound using the autoformer volume module was as close to absolutely neutral as any device I’ve heard.
As I look through my listening notes on the LIO, I notice that most of my comments were not about the sound itself, but about the music, and I consider that a good thing. The LIO consistently delivered music in a way that focused on the music. I was far more aware of the subtleties of microphone placement and the recording engineer’s reverb choices than of any sonic peculiarities unique to the LIO itself. But unlike many “neutral” components I’ve reviewed in the past, the LIO doesn’t sound matter-of-fact or mechanical. Instead it got out of the music’s way, and stayed out of the way.
A good part of the LIO’s relative sonic invisibility can be attributed to its noise-free character. It’s easy to listen into mixes, even thick, multi-element confections such as Fences’ latest release Lesser Oceans. Listening to a Hi-Fi stream from TIDAL via Roon and Amarra sQ+, I could hear deep into the opening tune on Lesser Oceans, “Songs About Angels,” and detect the multiple instruments subtly doubling (and tripling) the background vocal melody lines.
Another example of the LIO’s high level of transparency was that I could hear the improvements that Amarra sQ+ made on the TIDAL app’s sound quality. While subtle, its effect was pervasive, rendering the presentation more revealing and incisive. I also have started using Roon, which did not benefit sonically from being used in conjunction with Amarra sQ+ unless I had need of the sQ+’s EQ adjustments. Roon sounded especially good when playing back my 128x DSD live concert recordings through the LIO.
Using the LIO for headphone listening provided the same level of high-quality sound, so long as I paid some attention to matching the headphones to the LIO’s headphone amplifier. Since the LIO only has a jumper wire for reducing the overall gain, if you regularly go from high-sensitivity in-ears to low-sensitivity headphones you may find yourself spending part of your listening sessions removing and then reattaching the LIO’s top plate so you can access the jumpers. With “average” sensitivity-and-impedance headphones, including the AKG K-7xx, Sennheiser HD-600, Beyer Dynamic DT-880 250, Beyer Dynamic DT-990 600 ohms, Audio-Technica ATH 900X, or Audeze LCD-2, the LIO had no issues sans jumpers. But with any high-sensitivity earphones including the Sennheiser Momentum on-ear, Oppo PM-1, Oppo PM-3, Westone ES-5, and Jerry Harvey Roxannes, the LIO’s headphone amplifier needed the jumpers if I wanted to hear music emerging from silence.
To see how transparent the LIO was, I used the ifi micro iDSD as both a USB-to-SPDIF convertor and a full DAC into the LIO. (To clarify, both signal chains used the ifi micro to do the USB-to-SPDIF conversion, but one signal chain went straight to the LIO’s DAC and then its analog stage, while the second went through the ifi micro’s own DAC and analog circuits before being connected to the LIO’s analog section.) It didn’t take long to hear differences once I matched the output levels between the LIO’s DAC and the ifi micro (via its front panel volume control). The ifi analog feed had a drier, more brittle top end compared to the LIO. And while both feeds had equal soundstage width, the LIO had more convincing depth and three-dimensionality, in addition to better micro-dynamics. There was one area in which the ifi excelled: It could be adjusted to work with a wider variety of earphones.
If I had to identify any “weak links” in the LIO, one would be the headphone amplifier’s gain flexibility and the MOSFET power amplifier’s low power-output capability. Many speakers in medium or larger rooms will simply need more power than the LIO amplifier’s 45 watts into 4 ohms can deliver. Fortunately, due to the LIO’s modular design, it should be quite easy for Vinnie Rossi to design and deliver a dedicated high-sensitivity headphone amplifier.
Another development in the works is a new power amp. According to Rossi, “We are also working on a more powerful, external Class AB ultracapacitor-powered MOSFET power amp. It would be in an enclosure approximately the same size as the LIO, and the LIO could be stacked on top of it. It hopefully will be able to make a debut at the RMAF 2015 show, and should offer approximately 100Wpc into 8 ohms, 200Wpc into 4 ohms, and more into 2 ohms.”