What's the oldest piece of gear in your system?

This site is here for the buying and selling of Audio equipment. This causes me to wonder if most of us have relatively new equipment. If most of it is new, what is the oldest piece of equipment still in use, and why are you still using it?

My oldest piece is a Sota Star Sapphire, but it has been upgraded. It was originally purchased as a Sapphire in the 80's, but was upgraded to a Star Sapphire about two or three years ago.

What's your story?
Well, i can say the oldest pieces on my gear are my vintage Pioneer hp's. They have more than 20 yrs.
All my equip is vintage. But how bout 1979ish DBX 3BX expander.1980 ess eclipse M102 (hiel tweeter) speakers.also 1983 polk RTA 12Bs speakers.an old think 90's parasound HCA 1200 amp.benched @ 286w @ 8 olms I estamite around 400w @ 4 olms
My original Stax SRM1 Mk2, Lambda Pros with ED-1 Equalizer. I upgraded to a tube Stax driver with Signature phones, but I keep the old Stax as back up. Also, my three Nak cassette decks probably pre-date the Stax but are relatively new in my system in the last few years.