Hammond AO-10 D Preamp B2 C2. I’m not sure if it’s in working condition. It’s been on the shelf for 10 years. It was working when it was pulled to upgrade to an AO-28. It’s being sold as is for parts. 1 or the octal sockets was replaced at some point with an aftermarket socket. I’ve included an original used socket that could be wired in. Any questions please ask. Thanks for looking.