RCA OP-6 and OP-7 tube microphone preamp and mixer. Both units recently serviced with NOS RCA tubes installed. The MIC input on the front panel of the OP-6 has been replaced with a more useful impedance switch, allowing you to select between 30 and 250 ohms. For the OP-7, Ch. 1 is set for 250 ohms, while 2 - 4 are left at 30 ohms. Includes original covers, and custom Cannon to XLR adapters made with Mogami cables. The power cables have also been updated with standard 3-prong IEC connectors.
