You need about a 10dB pad. A suitable method, about 50 ohm in and out (view with fixed font)
High drive output
R1 Low drive input Out + --------- /\\/\\/\\/\\ --------- In+ / / R2 \\ \\ R3 / / Out - -------- /\\/\\/\\/\\ ------------- In- R4
Where R2 = R3 = 62 ohm R1 = R4 = 68 ohm
Vin -> 0.4Vp-p, Vout -> .125Vp-p, Rin = 47.2 ohm, Rout = 47.2 ohm
Cheers
PeteS