The funny thing is that Celestions at the time were considered to be crap. They improved over time as the market took off, but they were just cheap-ass speakers you could get for a couple of bucks.
When Peavey went to make the Sheffield, they wanted to make a vintage type. They actually had to outsource parts, as their own were manufactured too well to emulate a mid-60's Celestion.
No- there is a reason the market for Celestions took off. They happened to sound effin great for guitar. That's what Peavey has tried to recreate with the Sheffield. They wanted it to be as close as they could get to the original.
I didn't mean to imply anything negative about the Sheffield, for sure. Back then, tolerances were just looser across the board, that's all, and speaker manufacturing was not up to today's standards. Not as many companies made speakers just for guitar or pro audio. There were no PAs, no transistor radios, no Marshall stacks, no Mesa Boogies, no subwoofers.
Perhaps the Sheffields are modeled after the old 25 watters?Never liked those as much they reminded me of the EMC's,too loose for me..Different strokes