Vinnie Rossi LIO modular integrated amplifier

My girlfriend, "bb," a 6'-tall Aries artist, always says, "Math, science, religion, and even history, are all simply stories we tell ourselves about our experiences with a phenomenon we call energy."

My father, Herb Senior—the Deacon—always said, "The fundamental nature of the universe is vibratory—everything we experience is just waves!" He explained that waves—possessing power, amplitude, and frequency—are the basic building blocks of our reality. The universe actually "works" and is "comprehensible" because these waves are not random, but organized into exponential intervals called octaves. Our job, he told me, was to recognize and study this mathematical (and mystical) nature in action.

It's a shame that bb and the Deacon never met.

Meanwhile, I, your humble fabulist, have always claimed that when you listen to an amplifier drive a loudspeaker, the "sound character" of what you hear is determined directly by the strength, reserve, and basic electrical nature of that amplifier's power supply. Imagine an audio-frequency signal (a wave) impressed on an amplifier-plus-loudspeaker load and simultaneously modulating a standing pool of stored energy. Imagine that this stored energy is the medium (like water) in which the wave operates. Then, perhaps, you can see how the quantity, quality, and especially the "elasticity" of this stored energy determine how an amplifier sounds when reproducing recorded music.

Ultra DC
Vinnie Rossi of Red Wine Audio, a manufacturer of audio electronics, has turned understandings similar to the above into an exciting new power-supply technology used in his LIO modular amplifier. Instead of a conventional mains-transformer-rectifier-capacitor-regulator supply, Rossi's new design uses isolated rows of series-wired, high-capacitance, low-ESR ultracapacitors to store and release energy.

Rossi calls his new power-delivery strategy PURE DC-4-EVR. The availability of ultracapacitors so shifted his paradigm that, in contrast to his Red Wine Audio products, which run on battery power, the products sold under his own name are based on Pure DC-4-Evr. According to Rossi,

"This patent-pending Pure DC-4-Evr technology employs banks of high-tech ultracapacitors in place of conventional AC power or batteries. The ESR of the caps is approximately 0.002 ohm, so they can supply hundreds of amps instantaneously. You can arc-weld with them. They can also be charged extremely quickly. And yes, these are ultracaps of 350F (350 farads, or 350,000,000µF, each. Multiplied by nine but run in series for each of the LIO's (two separate) capacitor banks, the total capacitance divides by the number of caps used to net 33.89F per 24V bank. But yes, there are 6300F at 2.7V of total charge under the hood if they all were connected in parallel."

While one bank of ultracaps is delivering pure DC to the LIO's audio circuits, the other bank is charging. The LIO's audio circuitry is never connected to the charging capacitor bank, and is therefore always 100% isolated from the AC mains and its sometimes devilish discontents. Meanwhile, all the control circuitry is powered directly and exclusively from the 24V charger—which also feeds a dedicated 5V regulator for all logic circuits in all of the modules (see later). Rossi says, "LIO owners do not need expensive power filters, power cords, or conditioners to achieve ultimate quiet and musical resolution."

Walter Swanbon, of Fidelis Home Audio, in Nashua, New Hampshire, calls the Vinnie Rossi LIO the "Swiss Army knife of audio amplification." I agree.

The base LIO costs $2495 and, by itself, can't play music. It's simply a moderately heavy aluminum case with DuPont Corian front and side panels, a plug-in output module, a Pure-DC-4Evr ultracap power supply, and an all-metal remote control of black and chrome that is, by far, the most luxurious I've used.

To make this box operational, you must add modules. The LIO's base price as a remote-control line preamplifier, fitted with Input Select, Resistor Volume Control (RVC), Line output module and Tubestage is $3980 (price as of the time of writing), but it can be ordered with the LIO System Expansion Modules of the buyer's choice. The RVC module costs $395; the Headphone Amplifier module costs $695; the Tubestage, which uses the very "rolling-able" E88CC/6922 tubes, costs $795; the MC/MM Phono Stage, Digital Input, and MOSFET power amplifier modules each cost $895, the Phono Stage with remote loading control costs $1390; and the Autoformer Volume Control, which replaces both the RVC and the Tubestage, costs $1495. The MOSFET Amplifier module runs in class-A/B and offers maximum powers of 25Wpc into 8 ohms, 45Wpc into 4 ohms, or 65Wpc into 2 ohms.

In any configuration, the LIO is, to my eyes, the most attractive, well-crafted integrated amp I've seen. Vinnie Rossi's signature logo (with capacitor symbol) is a bit flashy but elegantly drawn. The well-proportioned case (available in black, silver, or combinations thereof) has the stylish feel of high fashion in Milano. I love the way the engraved aluminum top panel slides back to reveal an intriguing inner landscape of sturdy PC boards encompassing an entire red-blue-and-green garden of Performance Modules.

In the beginning
I first recognized the specialness of Vinnie Rossi's new LIO integrated amplifier while setting up a turntable for CNET and Stereophile writer Steve Guttenberg. As I worked, we listened to Technics SB-C700 loudspeakers (review in progress) driven by the glorious Pass Labs XA100.5 monoblocks ($16,500/pair). I kept looking up from the 'table and saying, "Steve, is it just me? Or is this, like, one of the best hi-fi systems I've ever heard?" He didn't answer. I whined louder: "Steeeeve! Is this the best hi-fi ever or what?" Still no answer. As I fiddled with the antiskate, Vinnie Rossi and Alexis, his partner in life and business, arrived.

Finally, I got the turntable together, and Rossi and Steve got the LIO hooked up to the Technics speakers. I can't remember the song, but it made me freeze in my tracks. What the . . . ? No way is this possible. All I can say is, when you replace amps like the Pass XA100.5s with any moderately priced integrated, you're supposed to feel grave disappointment. That afternoon, I felt shock and wonder. Right out of the box, the Vinnie Rossi LIO played music that flowed smoothly and silkily—and was noticeably more quiet and grainless than the venerable Passes.

The Slagleformer
That day at Guttenberg's studio, I was surprised to discover that Rossi is good buddies with an old friend of mine, master transformer builder and world-class audio polymath Dave Slagle, of Intact Audio. Rossi is also friendly with one of Dave's design collaborators, a very smart man named John Chapman, of Bent Audio. Rossi explained:

"I have been working with John Chapman for years with Red Wine Audio, as he was our OEM remote-volume-control supplier. When I contacted him about helping with the control circuitry for the LIO idea that I had, he was very enthusiastic to work with me, and has played an integral role in the design of all [of the] LIO's control circuitry, as well as . . . how the modules are neatly laid out inside the LIO. John is best known in the audio world for his autoformer preamplifier kits, using 'Slagleformers' hand-wound by Dave Slagle. I asked John to implement them onto an LIO module as a premium upgrade to the already high-quality resistor stepped-attenuator volume control (RVC) module that we offer."

For years, I've been using a custom Drug-Through-The-Hudson version of Slagle's Autoformer Volume Control in my monk's-cell reference system. Unlike other passive attenuators, which typically stifle musical life and dynamics, Slagle's tapped autoformer preserves, and maybe even enhances, the way recordings project energy into the room. When I replaced the RVC and Tubestage with the plug-in Slagleformer AVC (it took about 10 minutes), I experienced a dramatic increase in the music's dynamic life. Gain appeared to increase. Jump factor increased, and melodies played more vigorously.

With the LIO installed in my own system and fitted with the Phono module, Digital Input module, AVC, Headphone amplifier, and MOSFET amplifier, I auditioned it with LPs, through several loudspeakers.

Falcon Acoustics LS3/5a
The Deacon's favorite song was Stephen Foster's "Beautiful Dreamer." I doubt Dad knew who'd composed it, but every time he played it on his Columbia music console, he would say, "Shushhh! Can you hear the beauty?" When I played a recording of baritone Leslie Guinn singing this restful classic, from Songs by Stephen Foster (LP, Smithsonian-Nonesuch H-71268), I found myself in wonder at all the beautiful feelings and visions music can induce. Memories of my childhood came flooding back: flashing between my Bed Stuy bunker and my father's wood-paneled den in Chicago, I absolutely could hear the beauty.

The unique, iconic sound of dropping the needle on a black disc with the volume turned up—that attention-getting scratch of stylus on vinyl—shifted my memory machine into Drive. Almost instantly, I could hear Dad's voice and see his gold-toothed smile. The Rossi Tubestage plus phono stage presented my father's favorite song as a deeply felt lullaby. The LIO was extremely good at getting out of the way and letting this music have its way with me.

The LIO drove the Falcon LS3/5a's (which I reviewed in the August 2015 issue) with something approaching perfect tone. Timbres and textures were always-enjoyable constants, no matter which recording I played. The LIO showed me that grainlessness and high-relief textures are in no way mutually exclusive. Detail, drive, and forward momentum were as good as they get.

Vinnie Rossi
800 Main Street, Suite 125
Holden, MA 01520
(774) 234-0800

music or sound's picture

I hoped for an explanation of the main feature of the LIO. Each Ultra (or super) capacitor has apparently 350F with a max voltage of 2.7V and 9 of them have to be connected in series for each bank to reach 24V with 34F. So the statement of "6300F at 2.7V of total charge under the hood if they all were connected in parallel" is completely misleading because there are not connected in parallel. One bank is charging during the other supplies voltage separated from the charging circuit. As capacitors do not supply a constant voltage when discharging how is that voltage regulated? How often is a switch between banks necessary and does that switching have any influence on sound?

Vinnie Rossi's picture

Hi Music or Sound,

Correct - and Herb asked me about the total capacitance under the hood, which is 6300F worth of ultracapacitors. In use, each bank is approx. 38F (equivalent to 38,000,000uF) as 9 caps, each 350F, are connected in series.

You are also correct about the ultracapacitors not supplying a constant voltage (as they discharge). Over the course of approx. 10 minutes, they slowly discharge by about 4V. All modules downstream are linear voltage regulated, and the ultracapacitor bank in use always feeds them with a higher voltage than what we are regulating to.

Cap banks switching approx. every 10 minutes. It cannot be heard in the speakers or headphones. It happens very quickly (a couple of milliseconds) via relays switching the + and - terminals. Switching has no influence on the sound whatsoever, and at NO time is any of the audio circuitry connected to the capacitor bank that is charging, which is connected to the grid via an external AC to DC power adapter. So only DC enters the LIO. No internal power supply transformers. And the audio circuitry is ALWAYS 100% disconnected from the power adapter (which gets power from the mains). No matter how clean or dirty your power is, it has no influence on any of the audio circuitry because they always run isolated from it.

Feel free to contact me if you have any other questions. I'll be happy to clear things up for you. You can learn a lot from our website.

All the best,

Vinnie Rossi

Venere 2's picture

Are you related to Walter Rossi the guitarist? Ever build him a guitar amp :-)

dreite's picture

According to JA, the unit switches capacitor banks every three minutes with a 1WPC load and there IS an audible click. And the power amplifier performance is considerably short of the published specifications.
I also don't understand 60Hz (and components) making their way into the measured performance if the circuitry is "ALWAYS 100% disconnected" from the power adapter.

If your objective testing indicated better performance than JA measured, you should have noted that in your reply on the "Manufacturers' Comment" section of the print Stereophile. If he made a mistake in his testing, I'm sure JA would be more than willing to entertain an explanation(s).

John Atkinson's picture
dreite wrote:
According to JA, the unit switches capacitor banks every three minutes with a 1WPC load and there IS an audible click.

Audible in the quiet of my test lab with me sitting next to the amplifier. But with music playing on speakers, the click will be masked.

And forgive my impatience with the original poster, but he should have read the entire review before commenting.

dreite wrote:
I also don't understand 60Hz (and components) making their way into the measured performance if the circuitry is "ALWAYS 100% disconnected" from the power adapter.

Spuriae at the wall AC frequency and its odd harmonics are primarily due to magnetic interference, so as the LIO does not have a hefty power transformer and has that hefty ultracap supply, I was puzzled by this. I did check the possibility that my test equipment had some ferrous content, like the switches in the load resistor bank, but this did not appear to affect the LIO's measurements.

The noise and distortion performance of some amplifiers is approaching the point where factors like this can be seen. But the LIO's power amplifier module doesn't get close to equaling those amplifiers.

John Atkinson
Editor, Stereophile

CG's picture

AC remnants are really hard to get rid of in most test set-ups. The transformers in most - but not all - power supplies are close to saturation at some part of the incoming AC waveform, especially if there's junk on the ac power. This comes with the territory, especially with capacitor input power supplies. When the transformers reach that non-linear point of their magnetic properties, they tend to radiate a lot. This can very easily couple into the equipment under test as well as the test set-up itself.

There's thousands of references on this topic to be found in a Google search.

Vinnie Rossi's picture

Hi Venere2,

I am not related to Walter Rossi (or Carlo Rossi, or Martini and Rossi) - lol!

Hi dreite,

Since the review unit was made, we started applying damping material on the internal relays for the ultracap bank switching. If no music is playing and you are right next to the LIO, you probably will still here a slight 'click' when the banks switch. With music playing, I doubt you will hear anything from LIO (and certainly not in the speakers, headphone output, or preamp outputs).

Hi JA,

I was also puzzled why you measured some 60Hz components, especially since the LIO's power adapter is external (so only 24Vdc is fed into the LIO to charge the capacitor banks). Even using very sensitive IEMs (headphone jack), we could not hear the slightest bit of 60Hz noise or harmonics. I'm wondering if they were getting into the LIO via the external connections during the test process (maybe via the signal grounds)?

Best regards,

Vinnie Rossi

jmsent's picture

regarding the linear regulators in the power supply? Does that include regulating the supply rails for the output transistors? And, regarding the switching time between banks, I am assuming that the 10 minute figure you gave was with the amplifier in idle with no signal at the speaker terminals? JA got a much shorter switching time of 3 minutes with just 1 watt output, and I assume that would be shorter still at full output?

Vinnie Rossi's picture

Hi jmsent,

Yes, the circuity for every active module (e.g. dac, phonostage, power amp, etc) features linear voltage regulation. In some cases, multiple linear voltage regulators. For example, the dac has separate regulators for the clocks, the XMOS chip, the d/a chips, the analog output stage, etc. And no switching regulators are used for any module (no DC-DC converters).

Regarding switching between banks, the timing does vary based on how you have your LIO configured. Configured just as a dac, phonostage, or linestage w/o tubes runs longer than with the speaker output module, as there is typically less avg. current draw. If you have your LIO configured with the speaker output module, there is some quiescent current always being drawn when the speaker output module is ON, and there is also current draw that depends on the impedance of your speakers and how loud you play.

Running a constant 1W per channel via a test tone into an 8-ohm resistor will likely draw more average current than listening to music (except maybe when playing at loud levels and/or into lower impedance speakers). It is unlikely that the banks will be switching in less than 3 minute intervals, but it is still possible and it makes no difference if they switch every 3, 5, 7 or >10 minutes. The listener does not need to be concerned about this as the process is automatic and seamless. To the listener, the LIO is either turned ON or OFF like any other component.

Please let me know if you have any additional questions, and also feel free to contact me via email and/or phone call.

Best regards,

Vinnie Rossi

otaku's picture

Does John or Vinni or anyone else here have any knowledge or ideas about the similarities and differences between the LIO's Ultra DC supply and Bel Canto's Virtual Battery Supply (VBS), particularly in the C7r?

Vinnie Rossi's picture

Hi otaku,

They are quite different. From reading the VBS white paper, they are using a switch mode power supply (SMPS) that is always connected to the audio circuitry (not disconnected from it like a battery, or ultracapacitor banks as in the LIO).

Somebody please correct me if I misinterpreted this.

Best regards,

Vinnie Rossi

corrective_unconscious's picture

I don't understand the market for products like this: Apparently sophisticated and certainly expensive...but with so few watts. Bluetooth "capable" speakers strike me the same way, whatever their price level - they just don't seem to make sense as values. (Although I can understand people don't like cables.)

aslee's picture

Wonder if it can be powered by good quality SLA or LiFePO4 batteries?
If so, any further improvements in sound?