The old Club 47 was the place to go in Cambridge seven or eight years ago. You'd walk down those outdoor iron stairs at 47 Palmer Street into a dingy cave that held about 50 people you couldn't see. You'd pay your quarter or half-buck, and Tom Rush '64 would be sitting there, growling away.

Rush used to play at a lot of places like the 47. He performed at the CYO Hall in Fall River before a couple of hundred people; he'd play at bars where the manager would love your music and pay you two dollars a night.

Rush was tough in those days. Toughness was his hallmark. There he'd be on an album cover: blue jeans, cowboy boots, striding down the railroad tracks playing his guitar. Or looking out over something with a cigarette dangling out of his mouth. He might sing Bo Diddley's "Who Do You Love?" ["I've walked 47 miles of barbed wire, use a cobra snake for a necktie...."] He'd sing songs like that in his guttural voice.

He was the Marlboro Man, and every now and then he'd turn kind of wistful and sad --the cowboy sitting by the campfire at the end of the day -- and sing a soft song about a place he'd visited or a girl he'd loved. But he'd always get back to toughness: ["Them big city women sure do make me tried. Got a handful of gimmee. Got a mouthful of much obliged."]. He didn't sing social protest songs like Pete Seeger or Woody Guthrie. He was scornful of things in general.

So when Tom went artsy-craftsy, he made some of his fans from the old days a little angry. He didn't record for a while, and then came out with a new album. The cover was pink. Not blue or gray or black. Pink. On the cover was this freaky-looking guy with all kinds of tight curls and a cute moustache.

The music was still pretty good, but Tough Tom began sounding like Sweet Baby James. If you had wanted Sweet Baby, you'd have gone to him in the first place. Tom had gone from Marlboro Man to Flower Child, from King of the Road to touchy/feeley. He was no fool: he knew the time had come and gone for the short-haired cowboy with the guttural voice and the glint in the eye.

His concert last Friday was at Symphony Hall -- a long way from CYO Hall. His hair didn't have the curls anymore, but it was long and parted in the middle. The moustache was still there. He was wearing the blue jeans and checked shirt of days past, but the jeans were bell-bottomed and the shirt had a flowered print sewn on the front. All this was bottomed-off by track shoes. He was two, two, two Rushes in one.

His singing, too, reflected both sides. He did some of his new, mellow songs like Mother Earth. His best (our prejudice, perhaps) was "Who Do You Love," done as gutturally as ever, with side-kick Trevor Veitch on the electric guitar.

It was Veitch's last concert with Rush. The two had teamed up four years earlier. Veitch had been playing in the two-dollar (or less) a night bars in Toronto and the Canadian backwoods when Rush found him.

Rush did the audience the favor of letting Veitch play a couple of songs of his own, both of which were good and came from Veitch's experience in the Canadian backwaters. In many ways, he is the sort of person Rush was before Tough Tom got famous. At any rate, Veitch should do well on his own, which may, he said, involve playing in "a band you know, but whose name I can't disclose."

Veitch feels that the change in Rush was not the result of any desire to play to the new trends. "We had been doing the old stuff for too long and decided we wanted to do something different," he said. "So we got a band together and did some electric music. Whether or not it worked, we had a good time doing it."

Veitch and Rush were clearly having a lot of fun Friday, though sometimes their fun came at the expense of the audience. The Symphony Hall crowd was idolatrous, applauding Tom loudly for everything, even his barbs at them. Introducing "Rockport Sunday," Rush talked about the town of Rockport, how it's "apt to get a bit touristy in the summer." But then, a quick look at the audience: "It's organic." Big thousand watt grin. Peace sign flashed at the audience. Audience applauds. Performer chuckles.

The audience started applauding before the song was over. Tom looked up scornfully as if to say, "Not now children." Then, song finished, he motioned to the crowd to applaud louder and louder. He and Veitch laughed.

The problem with Rush is to separate the showman, the man on the pink album covers, from the songs he sings and the way he sings them. The fact is that he sang good songs and sang them well on Friday. His renditions of "Urge for Going" and "Dear Abby" -- a song "loaded with social significance," said Rush -- were very good. Particularly effective, because Rush seemed to have his heart in them, were "Rockport Sunday," an instrumental inspired by the sounds of the North Shore, and "Child's Song," a sad tune about a young man leaving home.

Unlike Pete Seeger, Harvard drop-out with social conscience, Rush, Harvard graduate with Urge for Going, wanted to make it. He didn't want to play in little bars all his life. Like many folk musicians who came out of the folk boom of the sixties, he was torn between the folk art -- which except in times of boom doesn't sell -- and some kind of popular success. He chose the latter, although he did some good singing in the process.

This sort of criticism may be unfair, especially in light of Veitch's remarks. "You don't want to get boxed into an image," Veitch said. "Doing the same thing all the time can make you stale."

No one can claim Tom has done the same thing all the time. When the folk world called for a King of the Road, Tom was there. When he thought the mood was shifting and calling for a freakier kind of image, Tom was there too. Now he's up in New Hampshire, presumably having a good chuckle about the whole thing.