Convert 10dbU to 4dbV with attenuation

Hiya,

I have two devices:

One professional DAC converter with a output impedance of 51 ohms, 4dbU output which can be balanced TRS or unbalanced TS jacks, whichever is easiest for this.

A consumer-grade amplifier which is 10dbV standard with 20k input impedance.

I want to build an attennuator to convert the levels and add 35-40dB attenuation as well, to the signal.

Been looking at a H-type attenuator, but not too sure on the resistors needed etc.

Any pointers for the best way to do this?

Thanks