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P a g e
Hookup, Settings and Adjustments
Before you start you will need:
RCA or XLR Interconnect cables from your sources and to your power amp.
Proper Care of the Leto Ultra Preamp
Very Important Read This First
The simple rule to remember is to “turn on the preamp before turning on your
power amp and turn off the power amp before turning off the preamp.”
Note:
Turn on your power amps after the Preamp LED’s have turned on. Not
doing so may create a very loud noise that could damage your speakers or other
equipment.
It is customary for vacuum tube equipment, when it is first turned on, while the
unit is powering up, to have a brief initial “hum” coming from the unit, not from the
speakers.
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 it on
Turn on the preamp using the ON/OFF switch located on the front left side. After
a few seconds the LED’s will illuminate and approximately 1 minute for the four
tubes should start glowing. The amber glow of the tubes as well as 4 LED’s
(mute, input, gain & presence) on the front panel will be the visible indication that
the unit is turned on.
Turn on your power amps after the Preamp LED’s have turned on.
If the LED’s don’t turn on, then turn off the unit at the power switch and unplug
the power cord. After waiting a few minutes unplug each vacuum tube in turn
(using the glove provided) and make sure that none of the pins are bent. If they
are please contact Zesto Audio for instructions.
