User Manual GC Audio 500 RACK
Thank you for purchasing the GC Audio 500 RACK.
We hope you have as much fun using it as we had designing it !
The GC Audio Rack 500 is a high-end 10 slot chassis with external power supply, compatible with all standard 500
series modules. The external linear power supply has a total capacity of 12 Amps (6A for the +16V circuit and 6A for
the -16V circuit) which makes it the most powerful 500 rack on the market. It easily powers the most demanding
modules by regulating them and filtering noise and parasites generated by the 50/60Hz AC current. The chassis is
made of 1.5mm thick steel, 50% thicker than other 500 racks on the market, offering excellent shielding against
electromagnetic radiation for optimal isolation of the 500 modules it receives.
Rack 500 is also available without external power supply.
Description :
External power supply for 2 Racks 500
GC Audio Rack 500 is delivered with an external linear power supply equipped with a 225VA toroidal transformer
followed by a 10A diode bridge, with ultra low noise, deported in an external steel case for a minimal electromagnetic
radiation. The power of this rectifier stage is necessary to support the high inrush current of the high capacity
capacitors that are required for a perfect smoothing of the AC voltage. Then, power transistors are added to put the
voltage regulators following the capacitors on steroids. This arrangement guarantees a very low residual ripple, a high
current capacity and an important resilience to inrush currents.
In addition to a very clean DC voltage and a high power availability, the "inductive" reserve of the circuit (typical
characteristic of linear power supplies with a large toroidal transformer), allows a very fast current response which
allows a high fidelity in the restitution of repeated fast transient signals, like with a drum.
Whether for the external PSU or for the Rack 500, the routing of the power supply rails has been established with the
greatest care (no autorouting!) with reasoned track sections and the necessary spacing to avoid capacitive effects. An
input too close to an output can quickly turn into a link of a few Pico Farads and lead to oscillatory phenomena at
high gain. Manual routing allows to avoid this kind of phenomenon. But also an optimized Top/Bottom ground plane
has been realized with screw feedthroughs to break all ground loops.
The external PSU has 2 outputs to power a 2nd GC AUdio Rack 500, which avoids the purchase of a 2nd power
supply. When using a second Rack 500, the total current available becomes 6 Amps for each rack which is more than
comfortable and remains the most powerful Rack on the market.
The Rack 500 contains two ground / lift switches which allows you to choose whether the ground (of the input and/or
output) should be connected to the chassis or to the Analog Ground. This function allows to break a possible ground
loop that can be created in any audio installation.
The linear power supply is equipped with internal safety devices to ensure safe operation. There is of course a fuse on
the mains side but also a fuse on the +16V circuit and another one on the -16V circuit. These protections can be very
useful when switching on a DYI module for the first time! A 110V / 230V switch makes it compatible for all countries.
Independent power on
The Rack 500 and the external power supply are each equipped with an independent power switch. It is therefore
possible to switch off the Rack 500 without switching off the external power supply. This allows the temperature
stability of the power supply to be maintained without unnecessary power consumption.
The front panel of the Rack 500 has a premium quality backlit power switch with a metal body and IP67 rating. This
means it is sealed against dust and moisture, ensuring a long service life. Metal body LED indicators for +16V, -16V
and +48V power supplies are also present.
Uncompromising construction
GC Audio's Rack 500 design starts with a more robust construction than the norm. Its chassis is made of 1.5mm steel,
solid as a tank! The thickness of the sheet metal is 50% thicker than the average and offers an excellent shielding
against electromagnetic radiation for an optimal isolation of the 500 modules it receives. It is coated with satin paint
for the front and back and a double layer industrial paint for the chassis. In addition to the studio application, its
