After 10 weeks of British rehearsals, then 10 North American dates, the Who was surely primed and ready to rock Philadelphia last night.

So too was the crowd of 55,000 fanatics that packed Veterans Stadium for the first of two sold-out Who dates here (the second is tonight). The showgoers were howling and waving banners a good half-hour before the rock legends hit the stage at 8 p.m., and they didn’t budge till 11:40 p.m., as the last notes of “Summertime Blues” were ringing in their ears. (At the echoey Vet, the concert sound always rings in your ears, unless you’re lucky to be positioned down front near the stage.)

Getting the most obvious business over with first, the Who launched the night with a spirited rendering of “Tommy,” their 1969 saga of the deaf, dumb and blind kid who’s exalted as a messiah. It’s a work the group grew tired of years ago, but it raised Pete Townshend, Roger Daltrey, John Entwistle and (the late) Keith Moon to the level of superstars in the United States.

Last night’s reading was abridged to 40 minutes (from the album-length 75 minutes) but managed to touch on most all the hits, from “It’s a Boy” to “Amazing Journey” (with Daltrey tossing his corded mike and kinda catching it, just like the old days). “Acid Queen” was nailed hard by new drummer Simon Philips (Moon would be pleased), and “Pinball Wizard” seemed improved with a jazzy five-piece horn section and bassist Entwistle’s cute allusions to the Beatles’ “Day Tripper.” Lacing “Wizard” more, a giant silver pinball balloon suddenly materialized over the heads of the audience.

Biting the bullet, the band even did “Welcome to the Camp” (a “Tommy” number Daltrey swore he wouldn’t perform), then “See Me, Feel Me” and the finale of “We’re Not Gonna Take It,” with the bathed-in-white-light audience singing along at the top of its lungs, almost drowning out the band. That was no small feat, given the massive speaker stacks the group had hidden behind rotating pop-art murals.

While their reading of the rock opera was certainly tight and tuneful, the augmented (15-piece) Who seemed to enjoy themselves more in the material that followed. Appropriate to the 25th-anniversary celebration theme that’s made this summer reunion possible, there were lots of glances back to the early days of the band, before it had made much of a name on this side of the Atlantic.

“In those days we didn’t have any originals, so we’d copy Chicago blues songs,” Daltrey explained before launching into a gutsy blues wailing of Bo Diddley’s “I’m a Man.”

Just as at the Who’s Glens Falls, N.Y., preview performance on June 21, Townshend traded in his acoustic guitar for an electric six-stringer at this point of the set. Moreover, he started to “windmill” strum and hit screechy high-neck notes just as he

[PHOTO CAPTION] Pop-art murals concealed megaspeakers as Roger Daltrey (left) and Pete Townshend performed at the Vet GEORGE REYNOLDS/DAILY NEWS

[PHOTO CAPTION] Pete Townshend: guitar wizard used to do as a showboating youth of 20.

(A couple of months ago, you might recall, the now 44-year-old Townshend proclaimed he “couldn’t play electric guitar any more because it hurt his ears. So he lied. Or he’s making a supreme sacrifice. His hearing loss is your entertainment gain. About the only thing Pete isn’t doing anymore is using a

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