Premier GA-8000 High End Tube Microphone
The GA-8000 microphone is a tube microphone equipped with a semiconductor
active cooling system that results in a higher signal-to-noise ratio
compared to most other tube microphones. It has a very high-quality
performance and modern sound character.
The GA-8000 uses a ROGERS ceramic circuit board that has superior insulation
parameters and offers a more stable performance. The coupling and bypass
capacitors are of a very high quality, resulting in a deep and exact low
frequency performance and a delicate and transparent high frequency
A semiconductor active cooling together with an external cooling
used in the GA-8000 to ensure that the GA-8000 has the highest
possible signal-to-noise ratio. The tube (a 6AU6) is mounted
in an aluminium casing, with the semiconductor cooling chip
being attached to the bottom of the case.
The temperature of the tube in the GA-8000 is effectively
kept down when the GA-800G is in it's working state, with the heat
generated by the tube actively dissipated. The heat that
the tube generates is transferred to the reverse side of the
semiconductor cooling chip and onto the outer aluminum
alloy heat sink at the rear of the microphone which then dissipates the heat
to the surrounding air.
A ROGERS ceramic gold-plated circuit board is used. This type
of circuit board is usually used in high-end aerospace
manufacturer with more than twenty years of microphone capsule
production experience are producing a capsule that has a
modern sound character and can
handle a high sound pressure level.
In order to ensure the tube will have a long life, we are
using a NOS CIFTE 6AU6 tube from France. The tube has a maximum
anode voltage rating of about 300V. The tube in the GA-8000 circuit
has an anode voltage of 90V and will generate more heat than
tubes used in many other tube microphones that typically uses
voltages between 35-50V.
The higher voltage used in the GA-8000 increases the heat
produced so the semiconductor active heat dissipation system is an
important element in the design.
The GA-8000 uses a modern power supply with solid state
rectifiers for the high voltage rail.
After a lot
of listening tests comparing a tube rectifying circuit with a
solid state one, we found that we did prefer the sound of the
latter so this is what we decided to use. The additional
advantage is that there is no need to worry about replacing
tubes in the power supply.