Coda FET Phono Preamplifier 06X - Manual (Page 9)

dESIgN PHILOSOPHy 9
diodes. The resulting voltage is heavily filtered and delivered to each stage through
independant class-a followers which completely decouples the stages. The resulting
non-reactive low impedance over an extremely wide bandwidth yields a perfect power
source for the individual circuits. The simplicity and absolute stability of the supplies
removes the chance of unpredictable interactions which may occur with the more elabo-
rate, high-feedback circuitry often used in similar equipment.
Most companies in the upper end of the audio industry use either sheet metal or formed
aluminum chassis. By contrast, the 06x has all structural parts made of machined extruded
aluminum. The advantage of this over an all-stamped chassis is that the machined
metal can be worked more precisely, allowing us to work on tighter tolerances and use
PC-mounted parts more easily. Moreover, such a design allows easier servicing either for
repair or for future upgrades. From the standpoint of appearance a machined surface
can be contoured in a far more pleasant manner giving the final product a more seam-
less appearance.
The amplifier’s chassis is made from heavy-gauge steel with a half-inch machined
aluminum faceplate. all exterior metal parts are anodized or powder coated for
durability.
Printed circuit boards are fiberglass epoxy with gold plating over a tin/nickel barrier.
The gold layer will not corrode, while the barrier layer prevents the gold from migrating
to the lower copper layer.
all resistors are precision metal film; 1% tolerance for 1/4-watt and 5% tolerance for
1-watt.
Capacitors have been eliminated wherever possible. No electrolytic capacitors are
used except in the power supply, where several high-capacitance electrolytics
provide outstanding filtering of the supply output.
all semiconductor devices are of very high grade. voltage gain is accomplished with
an extremely high-quality, matched dual FeT, chosen for it’s exceptionally low noise
characteristics.
all audio input and output connector contacts are gold-plated, and xlr receptacles
are manufactured by Neutrik of switzerland. wire is used as little as possible in the
signal path - only to connect the rCa jacks and speaker terminals to the circuit board
- and what is used is 141-strand silver-plated copper with silicone insulation.