Vinnie Rossi L2 Signature Preamplifier (Part 1—The Line Stage)

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Oh my, what do we have here? A full featured preamplifier from Holden, Massachusetts’ Vinnie Rossi, replete with live easy modules for digital and vinyl. And it’s not only a standard tube preamp, but one of the few starring the grail of sonic tubes, the 300B. Gold plated and a matched pair, no less. 

As a good friend in the industry continues to say to me, ’there’s always room for a full featured preamp’. Full featured, yes, but the L2 Signature is far more than that. It is full figured. And that’s not the half of it with this tank-like, but sexy behemoth from the pen of designer Vinnie Rossi. 

Rossi has received raves for the first components from his eponymous company, the LIO series, featuring a highly customizable preamp and integrated, with add on modules aplenty. The new Signature series advances his art and design acumen considerably.

The L2 Signature Preamplifier review will take place over three instalments. First, here in its primary line stage guise, then a follow up on both the vinyl and digital modules. Rather than stretch these reviews out, they will follow from my desk chronologically. Workmanship and design of this quality deserve very close attention. 

The Line Stage  

The Vinnie Rossi L2 Signature Preamplifier is Rossi’s flagship design. The MSRP is $16,995. As is typical with Rossi designs, this preamplifier is customizable. Both a phono stage ($3495) and a DAC ($3495) may be added to give the owner complete front end control of their digital and analogue domains. Be sure to check back for the complete look at this very functional high end art piece. 

I first noticed Rossi by his ads in other publications—each ad was exquisitely produced with high style and featured kit that caught my eye on a beauty and function level. I’m an audiophile who loves both visual and aural aesthetics. Rossi is one of those designers who obviously insists on both. All his gear is styled in a slightly retro, industrial way, but with a sheen that oozes super fine quality. Fit and finish are exemplary. Buttons and knobs are rock solid. Have you ever tested a boutique high end piece of tube kit that you worried would blow up with all that unharnessed, raw power hovering about? No worries with Rossi gear. It’s bulletproof. Nothing will go bump in the night. In fact, the soft start mutes the L2 for 25 seconds ‘till those glorious tubes are heated. No diving for the gain.

Rossi’s superb style and eye for detail also imbues his website with some of the best component photography on the web (many manufacturers, please copy).

Rossi explains the design of his L2 Signature Preamplifier this way: 

The L2 Signature Preamplifier is our new flagship design that creates an effortless connection between the listener and the music. Compatible with the most cherished of 4-pin directly heated triode (DHT) tube families, L2 delivers an unmatched listening experience with its exceptional resolution, tonality, and “reach out and touch the performer” sense of realism. Superb linearity and extra-wide bandwidth recover delicate nuances and provide incomparable texture, layering, and spaciousness. And when it comes to bass response, L2’s articulation of each and every note is phenomenal.

At the heart of the L2 Signature Preamplifier is Vinnie Rossi’s latest Class-A, ultra wide bandwidth, DHT topology powered by patented Belleson super-regulated, dual mono linear power supplies.  L2 exemplifies elegant simplicity and finesse in communicating all the emotion and passion in the music.

Each L2 Signature Preamplifier is meticulously hand-built and tested by Vinnie Rossi himself. Its no-compromise construction and use of the highest-quality components assure the listener of reliable performance for many years.

Pretty fancy writing about some metal and glass. Let’s take a look at the features and specs and get into it. 

 Features

  • Vinnie Rossi’s latest Class-A, ultra wide bandwidth directly heated triode (DHT) preamplifier design, compatible with: 2A3, 45, 300B, PX4, 101D, 205D, and SV811 DHT families with one-switch filament voltage selection.

  • Dual shielded power supplies with in-rush current limiting.

  • Dual-mono layout using multiple patented Belleson super regulators for ultra-quiet linear voltage regulation of the L&R triode B+, L&R triode filaments, and power to the (optional) L2 DAC and L2 Phonostage modules.

  • Discrete, 64-step resistor ladder volume control using Pickering England silent signal relays.

  • True active balanced (XLR) and single-ended (RCA) inputs and outputs.

  • Dual 12V Trigger output jacks with on/off control switch on front panel.

  • Internal, “DHT bypass mode” switches (Replaces DHT stage with a Class A JFET stage).

  • Internal front panel display & LED brightness controls.

  • Yamamoto solid Teflon UX-4 tube sockets.

  • Solid, precision CNC machined aluminum chassis and “bank vault,” ball bearing control knobs.

  • Solid, precision CNC machined aluminum isolation base with Stillpoints ULTRA MINI feet.

  • Mesh tube covers for added noise shielding and tube protection, with matching mesh ventilation on top panel.

  • Included tubes: EH300B Gold-Grid (matched pair).

  • Full-function aluminum remote control handset.

  • Designed and manufactured in the USA.

  • 10-year warranty.

Specifications

  • Frequency Response (with stock EH300B tubes): 2Hz – 500kHz (+/- 0.5dB); 0.5Hz – 950kHz (+/- 3dB)

  • Output Impedance (SE and BAL): < 100 ohms

  • Input Impedance (SE and BAL): Approx. 10K ohm

  • Voltage Gain: 8 dB (with stock EH300B tubes); 0dB (DHT Bypass Mode / Unity gain JFET buffer only) SNR (with stock EH300B tubes): -120dB (A-Weighted), SE IN/OUTSNR; (DHT Bypass Mode): SNR (DHT Bypass Mode): -140dB (A-Weighted), SE IN/OUT

  • 12Vdc Trigger Outputs: 12V (+/- 0.1V), 200mA max (each) with on/off switch on front panel

  • THD+N (with stock EH300B tubes): Less than 0.5% (unweighted), SE IN/OUT; THD+N (DHT Bypass Mode): Less than 0.0006% (unweighted), SE IN/OUT

  • AC Input: Factory configured for 110-120Vac -or- 220-240Vac (50/60Hz)

  • Volume Control: 64 steps (approx. 1dB per step) from -∞ to +8dB; Balance Control: 24 steps from L to R (approx. 1db per step)

  • Power Consumption (with stock EH300B Gold Grid tubes, L2 DAC and L2 Phonostage installed): Approx. 65W

  • Protections: Fused AC input; MOV (AC input surge protection); Output short circuit protection

  • Dimensions (With mesh tube covers and isolation base installed): Approx. 17.25″ wide x 14.5″ deep x 8.75″ tall (438mm x 368mm x 222mm)

  • Shipping Weight: 38 lbs (17.2 kg); 62 lbs (28 kg) including travel case

Rear panel  without  the phono and DAC modules installed. Look for photos of the installed modules in the following two reviews.

Rear panel without the phono and DAC modules installed. Look for photos of the installed modules in the following two reviews.

Delivery and setup

The L2 is was delivered in a military-grade, hard travel case. If your FedEx guy drops it, no worries. This thing is solid! Unpacking is easy and Rossi sent me truly idiot-proof, step by step instructions. He knows his musicians/reviewers.

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The solid metal baseplate is unpacked first and the main unit is screwed on to it. Feet (Stillpoints Ultra Mini) are adjustable. Everything is top quality and simple to setup. 

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The main unit is heavy, so lift with legs, or, even better, have a friend set it up with you. I used white ‘tube’ gloves to press the 300Bs into their sockets. The tubes are protected by a mesh cover which is the only part of the setup I was not fond of. Getting them absolutely vertical was difficult—the mesh always seemed a little off center. Eventually, they seemed straight enough. Rossi explained them to me this way after my ‘are these necessary?’ email:

To achieve the lowest noise/hum levels, they are necessary. Different direct heated triodes have different sensitivities to noise and hum pick-up in the L2 Preamp's circuit, but I have found that no matter which of the compatible tubes are used, the mesh tube covers ensure noise/hum is essentially eliminated. If you are not the type to put your ear up to the speaker to listen for hum when no music is playing, then you probably will not need them in place.

Mesh tube cover with the glowing EH300B Gold-Grid tube (one of a matched pair).

Mesh tube cover with the glowing EH300B Gold-Grid tube (one of a matched pair).

Electro-Harmonix Gold Grid 300B tube (x2).

Electro-Harmonix Gold Grid 300B tube (x2).

The unit comes with a superbly finished remote control. The same manufacturers mentioned earlier, please copy. If you have to charge a little extra to produce a beauty like the Vinnie Rossi, so be it. I complain every day to anybody who will listen about the absolute cheap and nasty plastic piece of nonsense that came with my $12,000 integrated amplifier. It doesn’t even have to be metal. Rega and Naim make superb, functional, very high quality, plastic remote controls. The metal Vinnie Rossi remote adds to the sense of pride owning such high quality kit. It’s a full functioning remote and can be used for the DAC and Phono modules, including switching cartridge loading and DAC filters on the fly. What a treat.

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My use

Rossi specifically asked me what amplifier I was going to use with his L2 Signature Preamplifier. I had a choice of three; Ayre, Prima Luna and my Jeff Rowland. Because I would have to use the bypass on my reference Jeff Rowland integrated, I thought I would borrow one of my buddy’s standalone amplifiers. It turns out, as I had suspected, the Jeff Rowland amp section of his incredible Continuum S2 Integrated Amplifier was a well nigh perfect match for Rossi’s 300B tube masterpiece. No blushes, either side. I used the Allnic Audio Mu-7R RCA Cable (review forthcoming) as bypass cables. Very high quality cables connecting very high quality components. 

The L2 unit was new with very few hours, so I played music casually for 20 or 25 hours before I began to sit down seriously. I will tell you, the preamplifier sang beautifully right out of the box. 

Because of tube warmup, etc, my protocol was the same as for the equally brilliant Allnic Audio H7000 Phono Preamplifier I reviewed a few months ago. I turned on the preamp as soon as I rose and turned it off last thing at night. The Jeff Rowland is on permanently as are the Mytek Manhattan DAC II, Antipodes Audio CORE Music Server and Sutherland Engineering DUO Phono Preamplifier (this last component doesn’t even have an on/off switch).

Before we get to the sound of the unit, a few words from our designer:

With the L2 monos being solid state, what was the thinking and choice behind the 300B for the preamp?

The L2 Signature Preamplifier is a "convertible," directly heated triode (DHT) design - the only one of its kind that I know of. By convertible, I am referring to how it allows for swapping of different 4-pin DHTs (e.g. 300B, 2A3, 45, PX4, SV811, 71A, T-100, 205-D, and others) via the filament voltage selection switch on the rear panel.

The primary goal was to use only the very best sounding of triodes (the 4-pin DHT families) in the linestage, where there is only one triode used per channel. No driver tubes.  No output transformers. No loading the tube with a loudspeaker, as these tubes are commonly assigned for in SET power amplifiers. No feedback. Just glorious, ultra-high bandwidth class A, line-level voltage amplification (~ 6 to 9dB of gain, depending on the tube used). It sounds simple and minimalist, but there is a reason why a design like this is not common - it is quite challenging to implement (especially with the incredibly low noise as the L2 Preamp).  We're talking super-regulated power supplies, 4-layer PCB design, and complicated grounding techniques that have taken a long time to perfect.  

The L2 Signature Monoblocks take this signal and give it the power to drive loudspeakers with a very linear, ultra wide bandwidth MOSFET stage that does not add the common solid-state sounding artifacts. The L2 Preamp is the heart and soul of the electronics chain. The L2 Monoblocks provide the muscle. So, unlike a typical SET power amplifiers, the L2 Preamp + Monoblock has much better power, bandwidth, dynamic range, bass impact and control—but with the attributes that I believe DHT's do better than anything else: a 'reach out and touch the performers' soundstage, rich tonality texture and spaciousness, realistic vocals (you hear a human body attached to them), top-end nuance, delicacy, and decay (better than the typical high frequency detail that any good amplifier can reproduce). 

Please let our readers know how you started in the business and your design/topology aesthetics?

I began Red Wine Audio in 2004, performing various modification services to components and also manufacturing a battery-powered, Class T amplifier (a variation of Class D using Tripath chipsets). My amplifiers that followed were class AB designs, and later they contained tube buffer stages on their inputs. The RWA product line also contained tube preamplifiers, DACs, Phonostages and headphone amplifiers—all of which were powered by internal battery packs and used external battery chargers.  

In 2014, I started the Vinnie Rossi brand with the LIO platform (a modular design topology using ultracapacitor banks), and in 2018 I introduced my flagship L2 Signature product line, which will include the upcoming L2 Integrated Amplifier (L2i) in the fall of 2019.

I have always strived to create highly innovative designs that compete sonically with more costly competition, and that are backed by stellar customer service and support. Each and every year I aim to raise the bar with my designs on multiple levels (e.g. sound quality, reliability, build quality, aesthetics, user experience), while keeping them manufactured in-house (Massachusetts, USA) and improving upon their quality and value to our customers. 

The high-end home audio design/manufacturing business has been and continues to be highly competitive. When you are a smaller company such as myself, it is very difficult to survive among giants unless you are deeply driven to create products the challenge convention and do things differently not just to be different, but because you believe that they communicate your passion and vision in this niche industry. It has already been 15 years for me (they do go fast), and while there are some days that I feel overwhelmed, there are more days that I feel like I am just warming up and there is so much more that I have in my mind that I am excited to bring to life one day.

Sound 

As Rossi suggests, the preamplifier is dead silent. No tube rush, nothing. A black background for the musicians to paint their sounds. During the break in, I had become enamoured with its sound during my standard sneak peeks. Warm, rich and refined, yet with incredible detail. All instruments shone with the most beautiful halo of vibrant sound. Vocals, too. Deep, rich, throaty. But with a harmonic ‘completeness’ to their presentation. Almost tactile. And definitely goosebump time. I could imagine the artists smiling and nodding with pride if they heard this type of playback. 

I’m guessing the 25 hours break in made a difference; it had to, right? Buggered if I know. The sound was so glorious after a few hours, I was already convinced and captivated. While playing digital files, I remember thinking ‘this preamp makes my digital sound like vinyl’. That sounds a little cliché, but there it was.

Albrecht Mayer’s oboe, for example, on a FLAC file of his new DG recording Longing for Paradise with all the air and presence I expect from good vinyl pressings. The overtones that make an oboe sound distinct (and often shortchanged on digital files) were heard in a timbre as thick as clotted cream with melodies phrased as beautifully as during his weekly Berlin Phil performances. I’m not sure whether it was Mayer’s playing or the Rossi presentation of his sound, probably both, that made me fall in love with this album? The recording also has some subtle orchestration—Elgar’s ‘Soliloquy’ orchestrated by my father’s instrumentation prof, Gordon Jacob, and played exquisitely by the Bamberg Symphony. Nothing escaped the Rossi’s musical embrace. Whether the most beautiful and moving nuance or the slightest stress on a note to make a musical point. Listen to the opening movement’s First Subject flute solo in Kirill Petrenko’s new Tchaikovsky Pathetique on the Berlin Phil’s own label to hear clearly what I mean (it’s on Qobuz in HiRes). The player makes the most subtle (and beautiful) change between the two imitative phrases at the very top of the second phrase. You won’t miss a thing. And like all great components, it draws you closer to the musicians’ intent.

The L2 enhanced my very fine digital setup, and considering the preamplifier section of the Continuum S2 (basically, a Jeff Rowland Capri II preamplifier) is outstanding and an obvious match for its connected amplifier section, it couldn’t better the gorgeous sounds the 300Bs were portraying. For sure, a completely different topology, but the way Rossi has his tubes singing is very persuasive.

It’s been my experience that some tube preamps let the side down during thunderous piano performances. No fears, here. Martha Argerich’s famous Berlin/Abbado/DG (vinyl reissue) of Prokofiev’s Piano Concerto No. 3 was overwhelming at times. She's a powerhouse; a force of nature. And all her power was unsullied and heard to astounding effect. Piano fans will love this preamplifier. Yet, at the other end of the dynamic spectrum, the Rossi retrieved even more subtlety from John Bingham’s playing of Schubert Songs arr. Liszt on Meridian vinyl than I’m used to. I use my late friend’s playing as a test for quiet pianism; pedal, bell tones, touch, ppp voicing, etc. This was pretty miraculous as a musical experience. The LP is available on Discogs. 

But what of the audiophile eschewing bigger and better boxes. A DAC/Streamer with volume, a Qobuz account and a set of powered speakers and I’m good to go. I’m afraid in their haste to downsize, they’re missing a lot. Maybe being that skinny works for them. But great preamps like the L2 add so much to a system. Audiophilia’s Karl Sigman had the same reaction after inserting his PS Audio BHK Preamplifier (from the mind of Bascom King) into his system. ‘How is it doing that?’. Why is it doing that?’. ‘What happened to a straight wire with gain?’. The same for my digital research of late—both Tidal HiFi and Qobuz sound so much better through my Antipodes CORE Music Server’s Roon Core than through the highly regarded Mytek streaming card add on module to the Manhattan DAC II and other streamlined digital setups I’ve heard (several at the recent Munich show, where skinny was good). Possibly, think of it as a journey between two points—one in a Chevette, the other in a swish ride. The L2 Signature is like adding a Rolls Royce to your system. 

The L2 was a lovely match to my recent build analogue system—starring the Bergmann Audio Magne Turntable. However, digital or vinyl, the Vinnie Rossi fit right in and highlighted the significant qualities of both formats. I think no matter your predilections and kit, the L2 will be an easy adjustment for your reference gear. I would suggest, though, quality needs to be matched with quality in this business. Why do you think Rossi was so interested in what amplifier I was going to match with his flagship? I’d have asked the same question. 

So, check back to see if the line stage played as beautifully with its phono and DAC add on modules as it did with my reference boxes.

Summary 

Adding this fantastic bit of kit will elevate your musical experience into regions you have yet imagined. Sure, it’s expensive, but did you see that parts list? However, it’s the sum of the parts and their implementation that produces the sublime sounds.

I have not heard stellar and expensive preamps from the likes of Audio Research (the REF6 at $14,000; I’m hoping to get one in for review this year) or high end extremes like Boulder Amplifiers (the legendary 2110 at $55,000; I may get to hear one at the end of this month), but I expect the L2 should placed on the same dance card. It could live in my system happily. Forever. Very highly recommended. 

Further information: Vinnie Rossi