Snom PA1+ to a Bogen Amp

Hello, I am connecting the PA1+ to a Bogen TPU35B. I am using the little connector piece that comes with the Snom in the line out port. I have that connected to the mic terminals on the amp and out of the amp on 70V and Com terminals. I am getting audio to the speaker but it sounds really bad. I saw a post somewhere and it mentioned using a STP-1 attenuator in between the Snom and amp. Has anyone done this before or have any suggestions on how to clear up the audio? Thank you for your time and input!