Asking Help! Source Output Too High for Headphones

I’m trying to find any opinion on the way to reduce the output from my source, a Sony XA5400ES CD player .I run the CD player to my headphone amp, either a iFi Pro ican, or a Woo WA22 amp. With any of my headphones.Which are high or low efficiency, high or low impedance, I can only turn the quantity up 1 or 2 notches, or below 9 o’clock.There is no volume adjustment on the Sony, unlike my Oppo 105D.
Can I put anything in-line to scale back the output?