I am an imaging junkie. Musical images, properly recorded, must have realistic tonality, unwavering stability, a rounded aspect, and—whether vocal or instrumental—must be room-present. Dr. John Coolege, a writer for TAS once exclaimed, "The music has blood in it." Zesto Audio's new Leto Ultra preamplifier is bloody wonderful, and USA made! George Counnas, the award-winning innovative audiophile designer of Zesto products, used his vast knowledge and countless listening evaluations to create the most elegant preamplifier of the decade...and it's only 2020.
George created a preamplifier that is neutral with a bullet, remotely changeable to enhance lesser recordings or sources, has remotely adjustable outputs that provide unity gain with no editorializing, and uses fully balanced tube circuitry throughout...all on one normal-sized chassis. Plus, it is a 100% ultra-quiet advanced tube circuit super easy to roll. Joining the Bia amplifier and the Andros Deluxe phono, the new Leto Ultra preamplifier premiers in excellent company—the three most innovative and dramatic advances to date of AFFORDABLE state of the art musical reproduction in the home.
The Zesto Audio Leto Ultra Preamplifier is Zesto's third preamplifier design, and also its most expensive. At $9995, it needs to be a lifetime purchase, in my opinion, an heirloom design if you will, and it is that most undoubtedly. In addition to its good looks—thanks to talented and creative designer Carolyn Counnas—George gives the audiophile his dream machine.
According to the Zesto website, these are the "Top 7 NEW Features of the Leto Ultra Preamplifier:"
- New upgraded circuit topology delivers more musical detail with a tighter bass. It has a robust input design to handle higher output sources. Dynamic range is expanded by new circuitry that produces a higher output before distortion. Still 100% Analog tube circuitry throughout the signal path.
- New tube configuration with the 12DW7 allows for the smoothest transition from the input section to outputs, providing the cleanest and most musical path for your signal.
- New 3 gain positions—dB, 6dB, and 9dB—make the Leto Ultra one of the most versatile preamps available. It easily accommodates the many volume differences from all your sources such as a high output DAC, as well as a low output phono. Your preferred gain settings are saved on each input and can be conveniently adjusted "on the fly" with the Remote or Manual control.
- New 6 inputs for your many sources include 3 true dedicated transformer Balanced Inputs and 3 Single Ended. All are high quality, gold plated connectors for better conductance and less corrosion for the most reliable connection.
- New 6 Position Presence Control adjusts the harmonic balance in the mid and high frequencies allowing you to dial back what you may consider to be too bright, edgy or aggressive. This is an exceptionally useful tool that addresses the inconsistencies of mastering from any source. It's easily adjustable "on the fly" with your remote or manually for each piece of music.
- New 9 button Remote control to conveniently adjust "on the fly" settings including Input, Volume, Presence, Mute, Mono, and Gain. In case you misplace your remote, all features can be adjusted manually.
- New LED indicators on the front panel clearly display all your adjustments.
Other important features you may want to know about
- No solid-state devices are used for switching the signals, only relays. This reduces noise and provides the most musical detail.
- The wide frequency response allows you to hear the finest passages in your music.
- Left and Right ground switches allows you to control the grounding of the outputs.
- The low impedance output transformers prevent the Power amp from affecting the line amp, thus providing the strongest and cleanest signal to your power amplifier.
- Recessed RCA and XLR connectors are premium quality, gold plated, with an isolated ground.
- All connectors are durable and will hold up to the typical Audiophile who loves to change their configuration.
- Automatically goes to mute when turned on or off, preventing any pops which could damage your speakers or surprise the hell out of you.
- The remote Mono feature helps you to trouble-shoot your system, especially phase issues, center balance and sound stage.
- Each preamp receives 50 hours of factory burn in on all circuits and vacuum tubes.
- Elegantly designed 16-gauge zinc plated steel enclosure to help isolate the electronic "chatter" from nearby equipment.
- On/Off power switch conveniently mounted on the front side panel.
- Each unit is hand-built "Made in the USA."
Basic Specifications
- Frequency response 10Hz to 40kHz ~ 2dB
- Distortion ~ 0.013% with 1V RMS input
- Signal to noise ~ 100dB below operating level
- Non-inverting output polarity
- Cross talk >90dB
- 1% metal film resistors throughout
- Polypropylene capacitors throughout the audio path
Let us not forget the unique essential double-ground switches, premiered by Zesto Audio with the Bia amplifier, which guarantees silent operation in your system, maybe for the first time ever. I had cheaters on my mono-blocks to prevent hum. I was able to remove the cheaters and just flip one of the Leto ground switches to achieve silence. This is quite special! By the way, in Greek mythology, Leto is the mother of Apollo.
The use of the 12DW7, now made by JJ, is a combo tube that is half 12AX7 and half 12AU7. This tube effectively eliminates two tubes from the circuit reducing one-third of the wiring plus parts. Less is more when it comes to distortion. First used on the Andros Deluxe, this special tube now provides for a fully balanced circuit, more balanced inputs, and higher definition.
The Big Deal: Presence Control
Everyone is talking about this feature, and calling it a tone control. That is like praising Caruso because he had a nice hum. The six position Presence Control, also on the remote, is adjustable on the fly. The positions were chosen to be subtle, the way an audiophile would do it. George did all of this by listening, not oscilloscope.
Presence Control Specifications
- 6 position remote or manual Presence control
- Presence 0,-1, -2, -3, -4, -5 (low pass shelf)
- 0 = Not engaged
- -1 = 13kHz and above
- -2 = 8kHz and above
- -3 = 4kHz and above
- -4 = 2kHz and above
- -5 = 1kHz and above
- When the unit is turned on, or you switch inputs, the presence control will go to "0"
- Presence control defaults to 0 which disengages from the circuit
This is not a scratch filter of old. It sounds to me like a gentle roll-off in the high band. The most gentle position is almost inaudible. Still plenty of air, you hear a bit of diminution in the highs and a slight solidifying of the mid-band. The second position is the most important to me. I found recordings that are bright like vintage EMI, Mercury, and Phase 4 to be about perfect at this setting with ideal balance and more definition. My friends, this is the adjustment we have been waiting for in this hobby.
The third position is more severe, and I did not find many of the records or CDs I usually played where this is needed. It clamps down rather notably on the mid-band. I did like a vintage Columbia Bernstein LP here...I set position three and turned up the volume a bit. It gave the Columbia more bass, and the overall presentation was more balanced. I never found a use for positions 4 or 5, but you might. The control resets to off/out of the circuit when changing sources or switch off.
Even when I thought the LP or stream was perfect, I tried position one or two anyway. I often kept it in the circuit. The Presence Controlled source just sounded more like real music in real space.
More More More
The remote control is a dandy. It mutes, engages mono, and more. All functions of the preamp are in your hand. It was not very particular about aiming and worked at a distance of 25 feet, which is where the Leto was placed in my listening room. The Leto was sitting at a severe angle to my listening position, and the remote always worked. I must compliment Zesto on the manual included with the Leto Ultimate. It is very thorough, and written in plain English. Very nice not to have to print one out.
Leto Ultra...the Sound
You already have a good idea of the musical performance of this preamplifier. I am mightily impressed. Using the outstanding new Cardas Clear Beyond XL power cord, I dropped it into the system with all of the same cables used with my reference. I did add the spectacular Audioquest Dragon power cords to my mono amplifiers.
The overall definition was as good as it gets. The highs are well extended and pure. The mids are dynamic and realistic. The bass is precisely an extension of the mids, right down to the center of the earth. It is very tight and percussive. The Leto Ultra tracked the sources preserving their integrity, which is what it is supposed to do. The sonic differences and manners of the new Grado Epoch 3 cartridge, the amazing Audios Mammoth Gold cartridge, and the Stein Aventurin cartridge were all easily distinguished and maximized by the Leto Ultra.
The Leto Ultra soundstage is grand. From ceiling to floor and wall to wall, and front to infinity, the speakers disappear and the music flows. With a state-of-the-art source, expect a state-of-the-art performance from the Leto Ultra.
The Leto is as quiet as if it were passive. No hums, no pops, no buzz—just silence. Ergonomically and musically it is beyond criticism. I tried to find some way to get it to reveal a problem, or blemish, or musical flaw, but it has none. When something musical popped up, a VTA adjustment or loose connection upstream fixed it. The Leto Ultra is a straight wire with lots of gain.
Tube Rolling (Warning, turn OFF the preamp before pulling tubes!)
Tube rolling could not be easier with the Leto Ultra. First up, I replaced the JJ 12AU7s with Mullard NOS. The Leto Ultra transformed to a warmer, richer, more liquid performer. The mid-band was more authentic, with piano and percussion becoming more fleshed out. Colors were bolder, and images had more shape. The highs were less noticeable and smoother. The records where I used the Presence Control required less adjustment, or none at all with Mullards. It was a different preamp, but equally stunning.
The bass lost some of its definition and power. It was big and bold, but not as continuous with the mid-range. I did like the double bass sound better with the Mullards, as I heard less string pluck and more box resonance. The Leto Ultra was more balanced with this instrument, particularly on jazz recordings. I did lose some of the skin sound on drums and hi-tops became brassier and less silver. Swapping out the JJs for the Mullards was a big change and easy to hear.
Next, I replaced the JJ 12DW7 with GE NOS. I put back the JJ 12AU7s to better isolate the tube differences. The GE tubes on the input of the Leto were only $25 each and made unpredictable changes. The exacting neutral nature of the stock Leto was preserved, unlike what happened with the lush Mullard swap, but the GE tubes doubled the dynamics, slam, and excitement. The definition was enhanced and clarity improved over the stock tubes without any degradation or added distortion. Musical colors were unaffected. Focus was sharper. I liked the GE tubes.
Finally, I tried both the Mullard and GE swap simultaneously to assess if this was the magic cocktail. It was not. The Mullards tended to smear the GE's energetic approach and create an unappealing cocktail. I would recommend either tube set on its own, but not together. What fun!
Summary
The Zesto Audio Leto Ultra Preamplifier is Zesto Audio's ultimate statement of preamplifier perfection. It is made 100% in America. The all-tube unit is chock full of useful and creative features a dedicated audiophile and music lover will enjoy, styling which would be right at home at MoMa, a flexible remote control without flaws, and Zesto's best overall musical performance to date. Sonically superior to anything solid state I have ever heard, you would have to spend a ton more to equal its high definition and many features in the tube world.
No tube preamp at any price is quieter or has better facilities to manage hum and noise in your entire system like the Leto Ultra. The Leto Ultra is one superior innovative product, and right at home in the Zesto line. My highest buy recommendation!
Leto Ultra Preamplifier
Retail: $9995
Zesto Audio
International Sales and Marketing
Carolyn Counnas
805.807.1841
