I used the following $500 item to burn in my gear recently. I took speaker wire to connect the amp to the device. The device is used for headphones. My CODA #8 amp has power meters. I was able to see the meters move even without headphones connected to the device.
Ribbon/Amp Interface • RAAL-requisite (raalrequisite.com)
BTW - I have 2 of these and only need 1 these days.