June 2021: The QA451 is out of stock. Given the limited availability of parts right now, we're trying to determine when another build can happen.
The QA451 is the replacement product for the QA450. The QA451 is designed for high-speed testing of amplifiers. If you are testing at the module level (with modules designed for single supply operation), the QA451 allows the on/off control and current measurement of the supply rail. If you are testing finished amplifiers (eg amplifiers that plug into a wall), then the QA451's programmable loads can enable fast automated testing when combined with the QA401 audio analyzer.