Zesto Audio Leto Ultra II
The Leto Ultra II comes with Zesto's new ESP power supply which is available as an upgrade for all Leto preamps
What is the ESP (Energy Source Power) Supply?
Zesto named it the ESP Supply because it anticipates the energy needs of the music. The new ESP Supply unlocks the true potential of the circuit, so it is at ease and doesn’t have to work as hard. It allows more music to flow through with more detail. It also creates a more dynamic presentation, the quiet passages are quieter and louder passages have more punch. The sound quality is an improvement throughout the frequency spectrum, so you have better clarity on the bass, midrange, and highs.
Here are the top 8 improvements:
- The transformer changes from an IE to a Toroid design, which generates significantly less noise because it does a better job of concentrating the magnetic field
- The high voltage increases by 17% from 250 V to 300 V which provides more headroom
- Dynamic range is increased from 2 dBV to 11 dBV, so the quietest parts are quieter and the louder parts are louder
- The ESP Supply is designed with bigger, fewer and heftier parts, which delivers more power with improved reliability
- The rugged design of the ESP Supply makes it more resilient to power surges.
- Both the high and low voltage supplies provide more current, so it’s less restrictive to deliver more music
- Maximum output level before clipping is increased up to 3 V RMS, depending on the unit to allow more punch
- In the Phonostages, the noise level is 5 dBV quieter, which increases the black levels considerably
The goal of the Leto Ultra is to deliver the most pristine signal from your audio sources to your power amps, without coloration. It offers lots of inputs and a variety of gain settings, and every adjustment is remote or manually controlled.
A unique feature of the Leto Ultra is the Presence Control, which was born out of the designer's frustration after finding some of his favorite recordings became unlistenable the more resolved his system became, regardless of the source. This new feature deals with the harmonic balance of the mid and high frequencies. Now you can easily adjust the balance for every song.
With the Leto in your system it will allow the sonic detail to come through, so you focus is on the music and the hardware will seem to disappear.
1. 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 features 100% analog tube circuitry throughout the signal path.
2. 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.
3. Three new gain positions 3 dB, 6 dB, and 9 db 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.
4. Six new inputs for your many sources include three true dedicated transformer balanced inputs, and three single ended. All are high quality, gold plated connectors for better conductance and less corrosion for the most reliable connection.
5. 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.
6. New nine-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.
7. New LED indicators on the front panel clearly display all your adjustments.
- 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 allow 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 troubleshoot 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 front side panel.
- Each unit is hand-built “Made in the USA”.
- 6 inputs with remote or manual controls
- 3 sets of true transformer balanced inputs (pin 2 hot) with an impedance of 10K ohm
- 3 sets of single-ended inputs with an impedance of 100K ohm
- Maximum input level of 7 V RMS
- 4 line outputs
- 2 sets of true transformer balanced outputs (pin 2 hot) with an impedance 150 ohm
- 2 sets of single-ended outputs with an impedance 150 ohm
- Maximum peak output level of 10 V RMS
- 2 independent ground-lift switches on the left and right outputs
- 6 position remote or manual Presence control
- Presence 0,-1, -2, -3, -4, -5 (low pass shelf)
- 0 = Not engaged
- -1 = 13 kHz and above
- -2 = 8 kHz and above
- -3 = 4 kHz and above
- -4 = 2 kHz and above
- -5 = 1 kHz 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
- 3 remote controlled gain settings of 9 dB, 6 dB, and 3 dB
- Manual gain switch on rear panel
- Gain setting is saved on each input
- Remote control Input, Volume, Mute, Mono, Presence and Gain settings
- All adjustments can be operated manually (just in case the remote is misplaced)
- Frequency response 10 Hz to 40 Khz ~ 2 dB
- Distortion ~ 0.013% with 1 V RMS input
- Signal to noise ~ 100 dB below operating level
- Non-inverting output polarity
- Cross talk >90 dB
- 1% metal film resistors throughout
- Polypropylene capacitors throughout the audio path
- Power consumption 28 W, 0 drain when off
- Voltage 110/120 V AC 60 Hz
- Standard 3-pin IEC power connector
- ON/OFF power switch conveniently located on the side panel
- Two internal high quality linear regulated power supplies, 250 V and 12 V
Vacuum-tube complement: 2 x gold pin JJ ECC82/12AU7, 2 x gold pin JJ ECC832/12DW7
Dimensions (WDH): 17” x 12” x 5”
Weight: 28 lb