Audiophilepure

https://www.headfonia.com/topping-dx9-discrete-review/2/

There are a few technical limitations worth keeping in mind regarding the processing window. Over USB and IIS, PEQ is supported from 44.1 kHz to 192 kHz at 16-bit to 24-bit. Coaxial, optical, and AES share this same range, while Bluetooth supports PEQ up to 96 kHz and 24-bit.

I also appreciate the memory logic Topping implemented. By default, the unit remembers the last-used PEQ configuration for each individual output. It then automatically recalls that profile the next time you switch back to that output, which is useful if you frequently alternate between headphone jacks and preamp outs. For those who want fast access, you can assign the PEQ toggle and preset selection to the knob press or to remote buttons to avoid menu-diving. Topping also included a crossfeed function with multiple modes, which is a welcome addition for headphone listeners.