Output and input impedance

What is the output impedance of Khadas tone board?

What is the minimum input impedance required by the amplifier to which the board will be connected.Thinking of Topping headphone amplifie,but input impedance of the said amplifier is 2.5kiloohm.

@Texmo32 @Gouwa @Eric68 Please help this.

Hi, The output impedance of Khadas tone board is about 100ohm. About the input impedance´╝îI think the concept is used for the Amplifier´╝îthere is no input impedance exactly for DAC product, But I think you may ask the output stage called LPF is an Power Amplifier,it is just a part of DAC, the input impedance of LPF is about 1.6Kohm.