Ultra Series
XPA U 358-70V

8x 35watts @ 70 volts

Status:

Active

Role:

Technical Resource / Systems Designer.
Power amplifier control systems, output filters, small signal stages and general system level logic and control.

Description:

This amplifier is a member of the newly introduced Ultra Series line of half rack amplifiers. All the amplifiers in this series have upgraded power and channel densities over their XTRA series predecessors yet retain professional grade THD+N and SNR figures, Energy Star qualification and power factor correction. Efficiency maximization was the cornerstone of this platform, which not only facilitated increased channel density but also eliminated the need for an empty rack space above the amplifier. This series includes low impedance, 70V and 100V and combo models. Other key features are <100ms wakeup time and less than 10W of standby power. The current Energy Star specification allows the standby timer to be disabled if standby power is less than 10W in amplifiers of this power class. As such, the timer is defeatable and the product remains within Energy Star standards.

Innovations:

Getting the amplifier to go in and out of standby quickly and quietly was a major design challenge. I devised a technique which allows the near silent power up and down of the amplifier stage. This was included in a pending patent titled Audible Noise Reduction in an Audio Power Amplifier for which I am credited as coinventor.

All Extron amplifiers utilize a patented technology called Class D ripple suppression. I improved the performance of this technology by retuning and optimizing the output filter that incorporated the ripple steering to increase the amount of loop gain possible, further increasing noise and THD+N performance without sacrificing ripple voltage.