I've got a tweed Fender Deluxe from the 50's. I've had it since about '89, played it on and off, and just pulled it out and played with it some more... So here's the odd bit. The label inside the cab says it is a 5C3, and it lists the tubes. A normal 5C3 has two 6SC7's, and that's what is printed on the label, but those are crossed out, and instead 12AY7 is written in. The amp actually runs 12AX7s. Opening up the amp, the circuit is for sure a 5C3, I've compared it to the schematic. The sockets and all wiring appears original (though I had some preamp caps replaced at one point). So has anyone heard of this happening? It's like a strange transition model between a 5C3 and a...5E3??? The 5D3 had 6SC7's as well. The amp has always been a bit woofy and woolly for me---too much umph and not enough kerrang or chime. I'm wondering if this frankenstein tube/circuit combo might be why.