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5 | 

P a g e

 

 

least six inches of clearance above the unit, 0.5 inch below and an opening behind the 
unit for airflow. Do not place the unit on a bed, sofa, rug, built-in bookcase, or rack 
without adequate ventilation. 
  
9. 

GROUNDING OR POLARIZATION: 

As a safety feature, the unit may be equipped 

with a polarized alternating current line plug in which one blade is wider than the 
other and has an additional grounding blade. This plug will fit into the power outlet 
only one way. If you cannot insert the plug fully into the outlet, try reversing the plug. 
If the plug still will not fit, contact a licensed electrician to update your outlet. Do not 
defeat the safety purpose of the polarized plug. 

  
10. 

POWER SOURCES: 

Operate the unit only from the power source indicated on the 

marking label on the back of the unit. If you are unsure of the type of power supplied 
to your home, consult your unit

 

dealer or local power company. 

  
11. 

POWER CORD PROTECTION: 

Arrange power supply cords so that they do not 

suffer from foot traffic or pinching by items placed on or against them. Pay close 
attention to cords where plugs enter the AC outlet and where they exit from the unit. 

  
12. 

LIGHTNING: 

For added protection during a lightning storm or when the component 

is idle for long periods of time, unplug the unit from the wall outlet. This will help 
protect the unit from lightning and power line surge damage. 

  
13. 

POWER LINES: 

Do not locate an outside antenna system in the vicinity of overhead 

power lines or other electric light or power circuits. When installing an outside 
antenna system, take extreme care to avoid touching the power lines or circuits; 
contact with them could be fatal. 

  

14. 

OVERLOADING: 

Do not overload wall outlets, extension cords, or integral 

convenience receptacles as this increases the risk of fire or electric shock. 

  
15. 

REPLACEMENT PARTS: 

When replacement parts are required, be sure the 

service technician has used replacement parts specified by the manufacturer or 
those having the same characteristics as the original parts. Unauthorized 
substitutions may result in fire, electric shock or other hazards. 

  
16. 

SAFETY CHECK: 

Upon completion of any service or repairs to the unit, ask the 

service technician to perform safety checks to ensure the unit is in proper operating 
condition. 

  

Summary of Contents for Leto Ultra

Page 1: ...wner s Manual Please read carefully before installing and operating this equipment Zesto Audio 3138 Calle Estepa Thousand Oaks California 91360 805 807 1840 www zestoaudio com Email george zestoaudio...

Page 2: ...about sound That s a good thing Each unit is built by hand with precision and pride to produce the most enjoyable listening experience for you I am proud to put my name on it and honored to share this...

Page 3: ...l Controls Page 10 11 Remote and Manual Controls Page 11 Vacuum Tube Layout Page 12 Hookup Settings and Adjustments Page 13 14 Tips and Tricks Page 15 16 Warranty Information Page 17 What s in the box...

Page 4: ...tructions with the suggested mounting accessory 4 WALL OR CEILING MOUNTING Do not mount the unit on a wall or ceiling 5 WATER AND MOISTURE Do not use the unit near water for example near a swimming po...

Page 5: ...on or against them Pay close attention to cords where plugs enter the AC outlet and where they exit from the unit 12 LIGHTNING For added protection during a lightning storm or when the component is i...

Page 6: ...ing code Questions about cables inside of walls should be directed to a qualified custom installer licensed electrician or low voltage contractor 18 RECORDING COPYRIGHT Recording of copyrighted materi...

Page 7: ...und lift switches on the left and right outputs Presence 6 position remote or manual Presence control Presence 0 1 2 3 4 5 low pass shelf 0 Presence feature is not engaged completely disconnected from...

Page 8: ...ctory installed 220V or 230 240V AC 50 60Hz Standard 3 pin 15 Amp IEC power connector ON OFF power switch conveniently located on the side panel Two internal high quality linear regulated power suppli...

Page 9: ...BAL Outputs 4 sets Two sets of RCA SE 2 sets of XLR transformer balanced outputs Left and right Ground ON OFF switch Connects or disconnects the ground to the Single Ended outputs Gain push button sw...

Page 10: ...en you change inputs Presence can be adjusted manually by turning knob or with the remote control Mono is adjusted by Pushing in this knob do not turn to adjust The Mono function indicated by the LED...

Page 11: ...tion Don t turn the knob to manually adjust Mute that will change your inputs Gain LED s will cycle through the three gain positions 3 dB 6 dB and 9 dB Adjust with the remote on the fly The Manual Gai...

Page 12: ...e Mute Preamp defaults to Mute every time it is first turned on and momentarily when you change inputs Mute yellow LED is located on the front panel with the input knob Press the Mute button for ON OF...

Page 13: ...s Warm up Allow at least 10 to 30 minutes for tubes to warm up to get the best performance from the preamp Power Carefully plug in the AC power cable to the preamp first then to your main power Turn i...

Page 14: ...it will sound terrible and wear out the tubes prematurely The sockets are labeled in order to correctly plug in the right tube in the right socket Using the glove provided unpack and carefully plug i...

Page 15: ...struments It does not boost or cut the bass or boost the treble but gently reduces the treble in the range that can become unpleasant The intent of the Presence control is to keep the essence of the m...

Page 16: ...for the output tubes Any damage caused by tube rolling is NOT covered by the manufacturer s warranty Mono for System Set Up I recommend using the Mono function primarily to help you setup and trouble...

Page 17: ...ers the use of12DW7 s and 12AU7 s in their proper positions To return the product it must be packed in its original packaging and returned to Zesto Audio or its authorized representative via insured f...

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