I shot a wedding with Sennheiser ew100 connected to audio output of mixer, the signal leaving the mixer from the dj was very strong.We reduced the signal to the Sennheiser ew100-30db signal and everything looks very strong.Today I bought a mini mixer Behringer 502, I install this mixer is in the dj mixer and Sennheiser ew100.
So I hope I can control the signal comes directly ew100 and not distort the audio, right? anyone tested this mix?
Thank you and sorry for English :-)

Normally the ew100 is set to mic level (-50db) If you feed it line level, -10dB or +4dB, you would likely overdrive the transmitter's input stage, regardless of the sensitivity setting. You should make up a cable with a (1/8 in.) 3.5mm TRS mini-plug where the (hot) + signal is wired to the connector's "ring", cable shield/ground to sleeve and leave the "tip" unterminated or tie it to ground. This allows feeding the transmitter -10dB's without overdriving (distorting) the input stage. You should use the Behringer's RCA tape out, assuming it's 10dB. If you are feeding it a true +4dBu you may need an additional in-line pad.
I believe this was discussed a while back, searching this forum may yield additional info.

Thanks Rick, I test mixer. ew100 are only 30db-up