Thank you for viewing. This is a listing for a set of 4 JRC4558DD dual operational amplifiers! Operation confirmed!! These are from around the early 2000s. They were removed and stored for modification purposes. 4558DD 8A01 x 1 4558DD G266A x 1 4558DD 2038B x 1 4558DD 8281B x 1 All ICs are used, but the operation has been checked using an IC check device (headphone amplifier). I have removed as much solder as possible, but some may remain. How about for the production, modification, or research of distortion or overdrive pedals? Shipping will be via Click Post, wrapped in aluminum foil and protected with air cushioning. Thank you.