Check the listing for details. Symetrix 581 E Distribution Amplifier Powers On, Untested Electronics. Color: Blue, Condition: For parts or not working, Made in United States. Listed at 46.16 USD. Powers on, untested otherwise so parts only. NO RETURN The Symetrix 581E Distribution Amplifier is a professional-grade microphone preamp voice processor designed for audio professionals in the music industry. This rack-mountable unit offers analog and digital capabilities, with built-in effects such as a mic preamp section, expander, compression/limiting, and de-essing. With its compact 4U rack unit height and blue color design, this amplifier is a versatile and powerful solution for enhancing and processing audio signals. Made by the trusted brand Symetrix in the United States, this unit is ideal for musicians and audio engineers looking to achieve high-quality sound results.