Specifications

I60 Owner’s Manual Ver 1.2
9
Maintenance
Periodically dust and clean your amplifier of the grime of daily living. Unplug
your amplifier from the wall before cleaning. Do not use liquid cleaners or
aerosol cleaners – just a clean, dry cloth. Do not use abrasive pads,
scouring powder, or solvents such as alcohol.
Adjusting the Bias
Your amplifier should give you years of trouble-free service. Re-biasing the
vacuum tubes will not be necessary unless you change the valves. However,
we have provided a simple means to do it.
The bias adjustment controls the amount of current flowing through the
tubes. Proper adjustment is crucial to the performance of the amp, and also
to the life of the tubes. The wrong bias setting will result in excessive
distortion and also shorten the life of your tubes. Do NOT listen to the guy in
the corner store who tells you that running the tubes “hot” will give you more
“slam”.
On each side of the I60, you will see a set of 5 little holes. Three of
the holes are for the probe of a multimeter, and two that give you
access to a little screw. Each set of holes is used to adjust the bias for
the two output tubes of a single channel (left or right).
You will need a multimeter that reads to 2V DC, and a small, flat-
bladed screwdriver. 2V DC is about as dangerous as playing with an
AA battery so don’t worry
about electrocuting yourself as
you do this.
Poke the red probe of the
multimeter into the hole
labeled (+) and the black
probe into the hole labeled (-).
Make sure that your usual
speakers are connected
securely, and then turn the
amplifier on if it is not already.
Using the small screwdriver,
turn the little screw between
the two probes slowly until the
multimeter reads 2 V. If you
have a very accurate digital