Hi-Fi circuit noise reduction
The Ferguson Hill FH007 is the first mass market horn based speaker system that Ferguson Hill developed. It is a desktop computer speaker system with an unsual look and very intimate sound. In 2007 during a mid-cycle redesign the PCB layout was outsourced and the result produced an audible hum in the left channel that was unacceptable in this premium product. Audio3 was commissioned by Ferguson Hill to identify, characterize and eliminate the audible hum.
Audio Ltd. developed a bespoke measurement system that could simultaneously and synchronously monitor multitple points along the signal chain. The automated testing of multiple sample systems allowed us to swiftly characterize the systems including unit to unit variability. This technique allowed us to pin-point all the noise entry points, showing that 80% of the noise entered through one poorly placed trace. We developed a shielding retrofit to block the noise at the major point of entry and then helped define new manufacturing criterion for absolute allowable noise at the output. The whole project was completed quickly and ended with a cost effective solution that reduced the noise at output by 85%.