Check the listing for details. AEA TRP500 500 Series Microphone Preamp. Condition: New. Listed at 649.00 USD. Clean Gain for Your Low-output Mics The AEA TRP500 packs the company's vaunted TRP preamp into a convenient 500 Series module. Like its predecessor, the TRP500 excels on low-output ribbon mics and dynamic microphones. That said, engineers at Sweetwater have found this high-performance 500 Series module to be an outstanding pre for any mic — period. It delivers 85dB of quiet, DC-coupled JFET gain, with an ultra-high impedance of 100k ohms. Simply put, the TRP500 captures the full, vibrant resolution of your low-output microphones without adding noise to your mix. This mic pre also packs a switchable highpass filter, switchable phantom power, and polarity reverse. Anyone searching for a great-sounding mic preamp with loads of clean gain will get lots of mileage out of the AEA TRP500.