Fiio am3 balanced amp module for x7 the am3 is a replaceableupgraded balanced amplifier unit that you can use to change the sound quality of your fiio x7 the balanced type am3 is designed for use to drive balanced headphones it has the 25mm trrs balanced output for balanced headphones earbuds as well as the 35mm single ended output for more common use the am3 has utilized the newly launched amp opa1622 from ti which is exclusively aimed at audio products the opa1622 is the newest additi