I am the original owner, purchased new from Vintage King in 2021. It's in excellent shape and sounds great. Jensen transformers, comparable to API 312 pre. Serial 2738. -Made using Avedis 1122 opamps -Supplied with Jensen input and output transformers -Switches have gold contacts for long life -High impedance direct input for guitar and synthesizer -Separate front panel switches for phantom power The 312A 500 series module is super fast and punchy, allowing transients to pass easily, making them a favorite for drummers. Made with the highest quality parts including Jensen input and output transformers and the Avedis 1122 opamp. The 312A also includes a high impedance DI for instruments.