I was using the Telex 5x5 in the ERJ. Take the headset to Radio Shack, show it to them, and ask for a volume adaptor. It kind of looks like those lamp cords that have the little rotating thumb switch built into the cord. You will also need to buy a plug adaptor for it also. The whole thing will run you about $10-15. It will get rid of the ear-piercing chimes and alerts in the cockpit.
If you want to adjust the gain, do what Skyway said with taking off the clip and adjusting the screw.
After that, it should work pretty good!!