Jason is right. Telefunken will do the job nicely. Should you go hunting on ebay look also under ECC83 Telefunken. If lucky, you will find German sellers, who are usually reliable and still have good merchandise. NOS Telefunkens are rare and very costly. But if you are offered old ones with good measurements I would grab them. They are built to last, even in difficult circuits, which the Paragon is not to my knowledge.
