Inputs & LEDs

The last PCB's are the Inputs and LEDs.
The Inputs PCB is a fixture for the USB-B connector with an ACTIVE LED that provides the control interface to the TAS3208 EVM, the optical audio receiver and the manual switch. This PCB is mounted at the back side of the shassis, next to the opening for the fans.
The 5V USB power from the USB host (PC) is only used to power the activity LED and provides a load to the USB host to keep the link active.
A USB-A connector is located on the INPUTS PCB looping through the data lines from the USB-B connector.
The USB power for that connector is provided by the 5.5V from the PAAS powersupply.
A standard mini USB cable is used to connect power to the TAS3208 EVM when in stand alone mode and support a USB host connection when a firmware update or remote control is needed.
The TORX AES/EBU optical link input is foreseen for future extension, its output is buffered by a SN74AHC1G125 buffer (IC2) and also powered from the PAAS powersupply.

The S1 manual On/OFF switch connections are routed to the ICC board.

The analog input cinch connector, mains switch and power cord inlet are directly mounted in the backside of the shassis.

The LEDs PCB actually contains two PCB's that are interconnected with a 40cm flatcable.
One half contains the LEDS plus driving logic and is mounted at the inside of the front of the speaker cabinet. The other half is mounted on the shassis.
In this way the shassis can be extended out the of the speaker cabinet without disconnecting the LEDs.
3mm acrylic rods are used to transfer the light from the LEDs through the 22 mm thick front of the speaker cabinet.
There are in total 4 LEDs on that PCB, A green "ACTIVE" LED, that is activated by the ICC board, a "DC error LED" and a "TEMP LED" that are controlled
by the Amp Fan Controller board and the "CLIP LED" that is an ORIng function (open collectors of the opto couplers) of the three power amp clip outputs
and the ADC clip output. For a longer lasting clip signal the duration the ON time of the "CLIP LED" was extended using a TLC555 timer (IC1)