- FiiO AM3B Headphone Amplifier Module for FiiO X7 and FiiO Q5
- 4.4 mm balanced output
- 3.5 mm output
- micro-USB charging port
The AM3B 4.4mm balanced/3.5mm single-ended output amplifier module is based on the AM3A,but has received key enhancements over it. Like the AM3A, which has proven to be a hit among audio enthusiasts, the AM3B also uses the highly-acclaimed AD8620 wide-bandwidth precision JFET operational amplifier in conjunction with two tailor-made OPA926 op-amps.
However, from here the differences begin. Exterior-wise, due to the extra length of the 4.4mm socket we could not use traditional layout techniques as this would result in the jack undesirably protruding from the rest of the amp module. In order to resolve this issue, FiiO engineers came up with some clever packaging involving two stacked PCBs that not only ensures we can fit a 4.4mm socket within our amp module, but also allows for further protection of the audio circuit contained in the module itself. In addition, a metal ring surrounding the 4.4mm jack also adds further strength to the connection.
Interior-wise, due to the two stacked PCB design's space savings the AM3B audio circuit design has some key enhancements over the AM3A. With the AM3B, we have been able to fully isolate the amplification and power supply sections, further optimize the power supply, and increase post-amplification stage operating voltage to 4.5V. All of these changes result nearly 100mW more of power in balanced operation.
Using the screwdriver included in the accessories of X7/X7 Mark II/Q5 to unscrew the T5 screws and exchange the headphone amplifier module. Although protection circuits are installed on the X7/X7 Mark II/Q5, it is still recommended to perform module exchange while the unit is turned off.
X7 Mark II (with AM3B) +F9 PRO: Due to physical size differences stemming from the 4.4mm jack, the AM3B does not fit into the X7 Mark II's original silicone case. Thus, included in the AM3B is a specially-made silicone case.