Hi, I'm new to Stax, got some Lambdas and now looking to get some Sigmas. I've had a normal bias pair offered to me for about £650, is this a fair price for Sigmas? Thanks

Hi,   I've inherited some very old STAX Lambda earspeakers and they sound great...but they are falling apart.   Does anyone know where I can buy replacement parts for these vintage cans? I need a new headband and new earpads.   Any help would be greatly appreciated.