The Audio Research EC-21 is a vintage two-way vacuum tube electronic crossover that lets you bi-amp your speakers like it's 1980 all over again. This isn't just a piece of gear; it's a ticket to audio nirvana for those who crave that warm, tube-driven sound.

S/N: 30212004

• Tested all tubes (Hickok 605a)
• Cleaned control contacts
• Verified operation
• Replaced feet screws