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Warning and Caution 

  
WARNING: 

The  triangle  with  the  lightning  flash  symbol  displayed  on  the  unit  advises 

the user of dangerous uninsulated voltage inside the product’s enclosure. 
  

CAUTION: 

To reduce the risk of electric shock, do not remove the cover. There are no 

user-serviceable  parts  inside;  it  is  recommended  that  only  qualified  personnel  service 
this component. 
  
1. 

OWNER’S MANUAL: 

Before powering up the equipment, read all safety and 

operating instructions and follow them as instructed. Retain the safety and operating 
instructions for future reference. 

  
2. 

ATTACHMENTS: 

Use only those attachments recommended by the unit 

manufacturer, as others may cause hazards. 

  
3. 

ACCESSORIES: 

Do not place the unit on an unstable cart, stand, tripod, bracket, or 

table. The unit may fall, causing injury to a person or damage to the unit. Mount the 
unit according to the manufacturer’s instructions 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 pool, bath tub, wash bowl, kitchen sink, or laundry tub) or in a damp 
environment (like a basement or outside in the rain). 

  
6. 

OBJECT AND LIQUID ENTRY: 

Do not push objects of any kind into the unit through 

openings as they could touch dangerous voltage points and short-out parts, possibly 
resulting in a fire or electric shock. Do not spill liquid of any kind on the unit. If water 
or any metal object (such as a paper clip, coin, or staple) accidentally falls inside the 
unit, disconnect it from the AC power source immediately and contact Zesto Audio 
for further instructions. 

  
7. 

HEAT: 

Position the unit away from heat sources such as radiators, heat registers, 

stoves, or other units (including amplifiers) that produce heat. 

 

8. 

VENTILATION: 

Slots and openings in the enclosure create ventilation to protect the 

component from overheating. All of these openings must remain unobstructed. Allow at 

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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