Vinnie Rossi interview: The man behind LIO, PURE-DC-4EVR, and the iMod


The always smiling Vinnie Rossi at AXPONA in 2016 with then new LIO DHT version.

Vinnie Rossi (of, and his effusive smile are a bit of a legend in hi-fi circles, especially on the show circuit. Rossi is always quick with a handshake, and never forgets a face or a name. In short, he always makes you feel welcome, and actually sets aside real time to talk with journalists covering the shows. I’ve never seen him turn down a music request either, something that definitely can’t be said for many manufacturers showing these days. Rossi very kindly took time out of his schedule to answer some questions I’ve been wanting to ask for a while now, so please read on, and feel free to join the conversation in the comments section.

RA: First off let’s talk about you, Vinnie Rossi the man behind all the unique technology that brings music to life for those fortunate enough to have spent time with your designs, or are listening to one at home now. Would it be safe to say that part of your start in the hi-fi industry came from the infamous “iMod” of the iPod that turned a not insignificant number of audiophiles on to the lossless-file format playback ability of Apple’s portable audio player?

VR:  “When I started Red Wine Audio (RWA) in late 2004, my first product offering was the Clari-T-Amp.  Clari-T was a low-powered (< 10wpc) SLA battery powered Tripath amplifier (“Class T”) that I consider to be my start in the hi-fi industry.  It was exciting because I had no idea that both customers, and reviewers would be putting it up against much more expensive SET amps, and proclaiming that the $500 Clari-T could hold its own in many ways.

Before I started RWA, I was modifying Toshiba SD3950 / SD3960 CD/DVD players on the side for various audio forum members and I believe this helped push me along into starting RWA.  During my first year in business, I offered modification services for a few different products.  I started with the slightly higher-powered Teac Tripath amp (model A-L700P), followed by the Slim Devices Squeezebox 2 and 3.  Then towards the end of my first year in business I began offering the iMod for the 4th generation iPod (which along with the 5th generation iPod that followed, contained the Wolfson d/a chip inside).”


iMod by Vinnie Rossi.

“When I introduced the iMod, most audiophiles believed the iPod was limited to MP3 files.  I remember often explaining how you could instead rip your music as WAV, AIFF, or ALAC (Apple Lossless) files for playback on the iPod.  Keep in mind that in 2005 audiophiles were just starting to get hip to “audio files” and they mostly thought of CD or CD-R when you mentioned digital audio.  Products such as the iPod, followed by the Squeezebox, started to change this, and we began seeing more discussion about digital file types, ripping CD’s, etc.  Those offerings began laying down the foundation of what we now simply call “computer audio,” which was still sort of taboo to the audiophile community at that time.  It certainly has come a long way, and continues to evolve!”

RA: It’s also my understanding that you have a background in electrical engineering, and worked for Lucent Technologies, did the work you performed there have any influence on your amplifier designs? Or was the hi-fi electronics modding you were earning a reputation for at the time completely separate from your day job?

VR: “Right out of college I started working for Lucent’s high-speed fibre optics division.  I was designing automated test sets (essentially large, multi-bay setups with lots of expensive rack-mount gear controlled by automated test software that I developed) to test high-speed laser transmitter, and receiver modules.  In the late 90’s and early 2000’s, wave division multiplexing (WDM) was allowing for the transmission of tens, and hundreds of gigabits per second (Gbps) of data, and sending that kind of bandwidth through a fibre thinner than the diameter of human hair, and over hundreds of miles required very careful tuning, and characterization of the lasers and receivers.  We were measuring the eye pattern at the transmitting and receiving ends, and other parameters in the digital domain.

So to answer to your question, what I was doing at Lucent did not teach me about analog amplifier design at all. Studying EE was a good start, but the rest came from being a DIY’er, and building, tinkering, listening, and reading audio design books and various websites/forums.  Audio component design is not a ‘spectator sport.’  You need dive in, and start building designs, testing them on the bench, tweaking them, and most importantly – listening to the heck out of them to understand what is really happening with any given circuit.  The listening part is always the most fun for me, and the most rewarding when I finally obtain the sonic results that I am after.”

RA: Were you always a music lover? Do you play any musical instruments now, or when you were growing up? If so, did playing an instrument help instruct your abilities into designing your amplifiers sonic-reproduction abilities?

VR:  “I never played an instrument growing up.  Instead of music classes, I took art classes.  As a pre-teen and teenager, I was deeply involved with art, skateboarding, learning about electronics and cars  – but music was always playing while doing these things even though I never played an instrument.

It was during my pre-teen and teenage years that I became a music lover.  I grew up during the time of the alternative rock explosion, and loved many of those bands (Pixies, Throwing Muses, The Cure, Smashing Pumpkins, Nirvana, Radiohead, etc.), and I was big into the 90’s skateboarding scene, so think lots of 90’s Punk Rock, Rap, and even some Metal bands.  My father often played music at home, and in the car, and I was listening to music from his youth (Beatles, Santana, Sinatra) as well as a lot of Pop and R&B music of the 80s and 90s that he was enjoying (Madonna, Suzanne Vega, Whitney, Janet, Sade).  My mother practiced yoga and gravitated towards Classical, New Age / World music (Bach, Mozart, Enya, Dead Can Dance, Ravi Shankar).  My older sister was mostly playing Rap, and R&B in her teenage years.  So from all directions I was listening to different genres of music, but it wasn’t really until I was in college that I started tuning into the local jazz, folk, and electronica stations, and began getting more immersed with those genres while staying up late studying.  Listening to lots of music helped maintain my sanity during my college years filled with gruelling coursework that never seemed to ease up since my first day as a freshmen.”

RA: You’ve been focused on keeping your amplifier designs off the power grid for many years now. Many of your first designs were based around Tripath amplification chips, it was this work that was the impetus for the initial idea of isolating your audio equipment from AC power. How difficult was it 12 (or more) years ago to source the type of specialized technology you required to make your idea of battery-based amplification a reality? What were some of the biggest technical obstacles you had to overcome during the prototype development phase?


Red Wine Audio Isabella preamplifier, and Signature 57 power amplifier.

VR:  “All the Red Wine Audio product offerings were battery powered.  For the first five years, they were based on sealed lead-acid (SLA) batteries.  The last five years was a transition to lithium iron phosphate (LiFePO4) battery chemistry.

The early RWA products such as the Clari-T-Amp, and the original Signature 30 had a simple ON/OFF switch, and with the charger always plugged in, OFF turned off the product and began the recharge cycle.  Sourcing SLA battery packs, and chargers was quite easy.  The problem was when you forgot to turn off the product and the battery would deeply discharge.  At that point the battery was either dead or its lifespan was significantly diminished, and it needed to be replaced.  Luckily SLA’s were not very expensive, but it was a pain for my customers to deal with.  That is when I decided that I needed a circuit board that would monitor the battery voltage, and automatically turn off the product and begin charging if the battery voltage fell to low.  I called it the “SMART” board (Seamless battery Monitoring, and Auto Recharge circuiT).  This prevented deep cycling, but SLA batteries in general didn’t have a long lifespan used in products like the Isabella tube preamplifier and others that I was offering that combined DAC, preamp, headphone amp, etc.  It wasn’t uncommon to have to change the battery pack every year or two, so that obstacle needed to be addressed.”


Custom battery pack insert on Red Wine Audio Isabella.

“I started playing with the newer LiFePO4 battery chemistry.  They offered much longer cycle life, but required a circuit board installed on the battery pack that monitored the voltage of each cell, and kept them balanced (nearly equal voltage for each cell), and protected from over-voltage, and short circuit conditions.  Otherwise, they could become a fire hazard due to the fact that the lithium-based battery chemistry was more volatile than SLA.  I had my own battery pack designed that would be able to fit into our existing products that were running on SLA, and it contained a built-in circuit board that did the monitoring/balancing/protection of the cells of the pack.  The price was significantly more expensive, but well worth it because once we transitioned to our LiFePO4 battery packs, the longevity seemed to increase by 5x or more.  This paved the way for me being able to include vacuum tube buffer stages in our existing product range and future RWA products.  The LiFePO4 packs had no problem with the added load and also allowed for charging/playing at the same time (just like you can with a notebook computer).  This was most useful for those who wanted to play longer than the typical 5 – 6 hours per charge.  Some listeners want music playing all day, and night, so I included a switch that would allow for pure battery mode, or “AC” mode that allowed one to play/charge at the same time.”

RA: Red Wine Audio is a company you oversaw for many years. RWA produced well-reviewed, and fiercely-loved – by owners – pre, power, and integrated amplifiers, mono blocks, phono stages, and DACs. You used LiFePO4 battery cells for your power supplies, and a battery management system that I believe you called SMART. How did this power supply/battery management system transform into the current PURE DC-4-EVR that current LIO customers are enjoying?

VR: “Being a geeky kind of guy, I was reading about ultracapacitors (also known as “supercapacitors” or electric double-layer capacitors), and quickly realized that they had large advantages over battery power:

1) They could be cycled (discharged/recharged) nearly one million times as they are inherently electrostatic, not electrochemical like a battery.  Even the best LiFePO4 battery cells that I was using were not rated for much more than 2,000 cycles before their lifespan was significantly diminished. 

2) Being that they are electrostatic, ultracapacitors can be charged very quickly (using high amperage) compared to battery cells that need to be charged at slower rates to avoid instability issues.

3) Larger-sized ultracapacitors have super-low internal impedance (those used in the LIO each have only 0.002 ohms of impedance), so they are able to deliver extremely high output current.

The drawback to ultracapacitors is that they have a lower charge density compared to a battery cell of the same size, so they discharge faster.  But as I mention above, they can also be charged very quickly – so putting these two facts together gave me the idea to use two banks of ultracapacitors.  One bank charges while the other provides power to the audio circuitry in a completely isolated fashion from the AC mains charging.  Then they swap when the bank providing power reaches a low threshold voltage.  I worked with John Chapman of Bent Audio on developing this (before this, John provided me with remote volume control kits for various RWA products).  John worked tirelessly on the microcontroller code to handle the bank swapping while I worked on the hardware design and testing.  We have a patent-pending together on this power supply technology that we decided to name “PURE-DC-4EVR” because that is exactly what it provides – pure DC current – with no play time limitations!  The user also no longer has to be concerned with replacing battery packs over time due to the very high cycle life of ultracapacitors.   You simply press the power button on the LIO and you are always getting pure, isolated, high-current DC power to all the audio circuitry.  The ultracapacitor banks seamlessly swap as needed.  There is no AC-to-DC conversion even happening inside of the LIO as we use an external power adapter to feed DC into the LIO, so there is no noisy power transformer contained inside.”


LIO with DHT 300B line-stage module.

RA: The new LIO line of products you are currently designing, and building are garnering rave reviews around the world, not in the least for their modular approach to construction. How did you come up with this concept, and can you talk about the benefits that the LIO design/circuit topology brings to customers?


Modular “bays” on the rear of the LIO.

VR:  “Throughout my 10 years with Red Wine Audio, I have always tried to offer our customers upgrades to the latest versions of our products. A strong loyalty to my customers is very important to me, and while it is natural for a company to come out with new and improved product models, I understand that many customers want to be able to upgrade to the latest version with minimal cost and inconvenience.  The RWA upgrades involved the customer sending back their product to me, along with lots of time on my end performing the upgrade.  I knew there had to be a better way going forward and envisioned a “product platform” approach that not only allowed our customers to configure a unit with just the options that they wanted, but also allowed for quick and easy upgrading via the swapping of modules installed on a “backplane” (motherboard).

The benefits of this approach, and fed from PURE-DC-4EVR, are substantial:

1) Ease of future upgradeability means LIO does not become obsolete, and in most cases, does not even need to be sent back to us for an upgrade.  We send the customer the upgraded module for them to easily install, and test out (30-day refund policy applies), and not only that, we offer 100% trade-in of the previous module towards the upgraded module so our customers do not lose any money or have to be inconvenienced with putting previous modules for sale on the used market.  As far as I know, no other company in this industry offers such a game-changing solution for their customers.  On top of that, everything is backed by our 10-year warranty.”


PURE-DC-4EVR at the heart of the LIO.

“2) Having the modules installed on our motherboard means they all receive the clean, isolated ultracapacitor power from our internal PURE-DC-4EVR supply, and the signal paths are optimized to be as short and clean as possible.  This eliminates the need for multiple boxes, interconnect cables, power cables, and avoids ground loops and the like.

3) With LIO’s modular “system approach,” our customers can configure a LIO that meets their current needs today, and easily add features later as their needs change (e.g. if you later get into spinning LPs or headphone listening, you can easily install the LIO Phono stage, and/or LIO Headphone Amplifier modules at any time).

4) Since all of the modules (the audio circuitry) inside LIO are fed from LIO’s isolated, PURE-DC-4EVR power supply, there is absolutely no need for any power conditioning products, upgraded power cables, etc.  They have no influence on the sound because the sound you experience with LIO is always powered from an isolated ultracapacitor bank.  You can have the noisiest AC power imaginable, and it will have 0% influence on the sound quality of any of LIO’s modules.  This is another game-changer for our customers!”

RA: Is there a limit to how much output your designs are capable of producing? Some audiophile consumers are of the “more is better” school when it comes to watts (I’m not one of them), so I wonder if there’s any pressure on you to continue to push the limits from a power output standpoint? Is current a more crucial factor to you in amplification design than wattage?


Modular, off-grid, incredible tone, dynamics, and transparency to source: The LIO.

VR:  “Well, the output current of PURE-DC-4EVR is virtually unlimited as far as speaker amplification applications are concerned.  However, we are running on a 24V rail, so this limits maximum output power if the design is left as is.  I am currently working on a more powerful “LIO MOSFET AMP 2.0” module that uses custom autoformer outputs that convert current to voltage and I am looking to deliver around 75wpc RMS into 8-ohms and > 100wpc into 4-ohms.”

“LIO customers that need more power can also use the preamp outputs to drive external power amplifiers (e.g. our VR120 stereo power amplifier or mono blocks).  The majority of our customers find LIO’s MOSFET AMP acts like it delivers more power than the specifications suggest, and are pleasantly surprised by this with their speakers.  So while there hasn’t been much pressure for more output power, I believe offering more power as an internal option for LIO will help lure in customers who would like to see higher power, and it would still be a high performance Class AB MOSFET output stage.”

RA: All of your previous RWA designs have people’s names (Lilianna, Bellina, Isabella, etc.) can you talk about this convention, and does LIO stand for anything?


Vinnie with daughter Isabella.

VR: ” Isabella is my first daughter.  Liliana is my second daughter.  My wife’s name is OiWah.  So when coming up with a name for this new Vinnie Rossi platform in 2014, I decided to use the letter of their first names and came up with LIO (pronounced “Leo,” like the constellation).  I just had another daughter last November, Lucia, so I’ll have to figure out how to incorporate her name into the mix at some point!  L2IO?  :-)”

RA: What’s next for Vinnie Rossi? Can you talk about any new products you have coming out or that are in the prototype stage? The MINI PURE-DC-4EVR comes to mind, can you explain the concept behind your latest creation?


Mini PURE-DC-4EVR at RMAF 2016.

VR: ” The MINI PURE-DC-4EVR uses our patent-pending PURE-DC-4EVR design in a smaller, scaled down version that allows users to power devices that operate in the 3.3V – 12Vdc range (2.5A max continuous current).  As with LIO, the MINI’s DC output power is fully isolated from the AC Mains.  Devices such as the Sonore microRendu, Auralic Aries, and many others that come with a cheaper “wall wort” ac/dc power adapter can deliver greater performance when fed with our clean (Belleson super-regulated), isolated DC power.

I am currently exploring a larger power supply that would use a scaled up version of PURE-DC-4EVR feeding a DC-to-AC conversion (pure sine wave) stage and regenerate clean 120 or 240VAC power for those who are using products that only accept AC mains power.  This would actually be the world’s first fully isolated, ultracapacitor-powered AC regeneration product.

For LIO, new modules are always in the works.  Two of them are specifically designed for the upcoming Spatial Audio X1 Uniwave open baffle loudspeakers: 1) A four-channel amplifier module with fully active crossover and EQ (all in the analog domain) to feed the Spatial X1 drivers, and 2) A four-channel, line-level version of (1) above for those using external amplification.  These should be available starting later this month.

An even higher-performance “LIO DSD/PCM 2.0” DAC is coming this spring, as well as the higher power “LIO MOSFET AMP 2.0” that I mentioned above.  Beyond that, we are looking into offering a streamer module for LIO (e.g. something like a microRendu, but built onto an internal LIO module) and a few other secret projects.

Thank you for this opportunity to answer your questions and share my response with your readers.  See you at the next audio show!”



Thanks again to Vinnie Rossie for his time on this interview.

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4 Comments on Vinnie Rossi interview: The man behind LIO, PURE-DC-4EVR, and the iMod

  1. SlickWilly // February 11, 2017 at 8:50 PM //

    Poor Carl. Poor, poor, miserable Carl.
    The wood box you must be referring to is clearly your head.

  2. What a constructive comment! His ‘cutting edge’ is the stuff not in the wood box…

  3. Carl Engeb // February 10, 2017 at 4:38 AM //

    UL listed? electronics in a wood box, is hardly cutting edge

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