a friend of mine gave me a ‘66 Deluxe Reverb that was original. It needed an electrolytic cap job and a going over. I played it on my bench for days using a Reverb spring I keep in my shop. All is well, everything great. Put the chassis back in, plugged in the original tank and played. Reverb signal WAY lower. Put my tank back in, Reverb fine again. So, I know tanks are just coils and transducers and values won’t drift as in resistors. But the old tank is seriously cold. What do you think? Have you heard of cold Reverb tanks? Just a bad one from the factory? It’s been in there 50 years. I’m going to give him my spring.