Introduction

Classé updated their Delta power amplifier series in late 2010, including the CA-M400 which is now the CA-M600. The entire amplification signal is conducted on a single circuit board, and they have introduced a new cooling system called ICTunnel™, which utilizes a fan in the front at the air intake where the cover is flush with the front panel. The air flows around an offset cover plate and past specially spaced fins which are inside the chassis and which provide about 31 square feet of surface area, which makes the cooling system very efficient.

The air does not flow over the circuit boards, because this would result in dust from being pulled onto them, which would degrade performance over time. The circuit boards attach to the outside of the cooling tunnel and air passing through the tunnel draws heat away from them into the fins. In use, I found the fan to be whisper quiet, with just a gentle breeze coming from the front amplifier port. This kept the entire chassis cool, but also, the temperature of the circuit board is electronically controlled by adjusting the fan speed, to optimize the performance, which turned out to be stellar.