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NEW POWER TUBES
The
OptiBias™
circuit works best with tubes in the big middle section of the “bell shaped
curve” and so this is what we provide with your amps. This is also what we will provide
for you when the time finally comes to replace them. Therefore, we recommend that new
power tube sets only be bought from CAT.
DO NOT SUBSTITUTE DIFFERENT POWER TUBES! This will invalidate your warranty.
NOS DRIVER TUBES (SMALL TUBES)
We provide the best driver tubes ever made for your CAT amplifier. These tubes provide
the most natural sound quality, and your amplifiers have been designed around them.
However, feel free to experiment if you wish!
MECHANICAL GROUNDING
Your
amplifier is equipped with high loss visco elastic feet which do a very good job of
isolating the amplifier from structure born vibrations. In most situations these will be the
best sounding feet to use.
In cases where the floor is particularly vibration free, especially if the floor is on a
concrete slab, you may get slightly better bass definition by coupling the chassis directly
to the floor. This is best accomplished by using Audio Selection cones. Two are in the
back and one in the front. DO NOT remove the open cell foam on top of the foot, as this
prevents the chassis from chattering against the top of the foot. It is not necessary to
remove the protective layer and actually glue the foot to the bottom of the chassis. There
are other good devices available as well but under no circumstances should you use any
device which places a flat hard surface in contact with the amplifiers chassis. Such devices
always create mechanical resonances which are claimed to enhance “detail”. Your CAT
amplifiers are the most transparent amplifiers in the world. Mechanical noises which
masquerade as “detail” with lesser amplifiers are instantly revealed as false with your
amplifiers. If you must place a foot with a hard surface under your amplifier please put a
piece of felt between the cone and the bottom of the amplifier.
TUBE DAMPERS
Don’t use them
