Amplifier manufacturer QSC is known for its lightweight, live sound/touring amps. However, the company has added installation/contractor amps to its line of products with the introduction of the CX series. The CX168 ($2,450) promises to shake up the class with a feature-laden, value-oriented amp package.
Product PointsApplications: Contractor/installation
Key Features: Eight-channel; multiple channel configurations; DataPorts; QSC PowerWave technology; security cover
Contact: QSC Audio at 800-854-4079 Web Site
The CX168 is an eight-channel amp in a two rack-space chassis. Each channel has its own separate attenuation control, signal present LED and clip LED. The channels are grouped in pairs that can operate in bridge or parallel mode and each pair has a bridge and parallel LED indicator. Input connections are via detachable, high-density Euro connectors and QSC DataPorts. Speaker outputs are via detachable high-density, high-current screw plugs that accept stripped wire ends.
The CX168 is, in some respects, similar to other QSC amps (such as the Powerlight and PLX models) that utilize the PowerWave switching power supply; it consumes just two rack-spaces and weighs only 21 pounds. All of the PowerWave amps are known for their excellent power delivery, low sag, inherent absence of AC hum, efficiency and reliability.
There are some areas where the CX is starkly different from its PowerWave stable mates. For one, this amp has eight independent channels. They can be configured as eight mono, four stereo, four bridged, or variations combining these modes. With eight channels providing a claimed 140 watts at 4 ohms (measured at 1 kHz, 0.1 per cent THD with all channels driven), the CX168 is capable of delivering ample power to multiple zones. (See bench test for actual power measurements).
Need more power for one zone or speaker? Just bridge a channel pair (1/2, 3/4, 5/6 or 7/8) and you have a 260-watt (8 ohms) channel with six others still available.
In a conventional amp design – with all these channels plus bridging capability – there could be problems. Since all the channels operate from a single power supply, potential exists for a bad channel to take out the whole amp.
QSC solved this potential problem by giving the CX isolated transformer windings and individual fuses for each channel. Each channel uses QSC’s “AC-coupled,” DC fault blocking system. This safeguard prevents DC faults from reaching the load – regardless of the fuse status and without shutting down the main supply. Also, the fan speed is dictated by the hottest channel, ensuring that thermal problems will be minimized.
The CX168 also has four DataPorts that allow access to information regarding output voltage, output current, operating temperature, clipping and protect activity, bridge mono and parallel status, power supply voltage and power standby status.
The CX168 can also accept audio inputs via the DataPorts and a multipin cable can connect the CX to a CM16a amplifier network monitor for remote control. The DataPort enables the user to utilize other accessories such as digital signal processing (crossover, limiting, filtering and delay). The CX168 also has four DIP switches blocks (one for each channel pair) similar to those found on other QSC amps. These switches allow you to control functions, such as stereo/parallel/bridge mode, clip limiters and low-frequency filters.
When it comes to fixed installation applications, the CX168 goes for the brass ring. With features such as variably configurable channels, small footprint, on-board limiting and filtering, ports for external DSP and remote control, this amp is a contractor’s dream. Add in the security cover and QSC’s watt-per pound ratio, and the amp is nearly perfect.
Restaurants, museums, theme parks, schools and bars are just a few of the locations this amp is designed for. I even used the CX to power multiple monitor mixes for a jazz group. I used bridge mode to power four 200W monitor cabinets that were loaded with 12-inch Eminence woofers and one-inch horn drivers. In all my uses, the audio was clean and never harsh, with tight bass and clear treble.
At $2,450, the QSC CX168 is a best-buy contractor amp that is loaded with innovative and useful features. With QSC reliability, it is a safe bet that the amp is destined for numerous installations. Wish they would make a high power, multi-channel version for live sound as well.