Keep jamming, kids. Take it from Randy Bachman.

True story: American Woman started as a jam in the key of "E. Takin' Care of Business was a jam in "C" and You Ain't Seen Nothing Yet was a jam in "A." They just, you know, grew from there. He calls the latter pair of BTO hits his "two greatest mistakes." You could buy a house and a garage to jam in with royalties from just one mistake.

"I have a few keys left," Bachman laughs, "So I can try for another couple of hits."

But not just yet. He's no fool. Neither is Burton Cummings or the rest of the Guess Who, who perform tonight at Skyreach Centre. They know the most dreaded phrase heard at classic rock concerts, the words that strike fear into the baby boomer's heart: "We're going to do a few songs from our new album now."

Generally speaking, a fan's desire to hear new material from an old band is inversely proportional to how many years it's been since the band's last hit. Multiply that by how many hits there were - "lots" to be precise, in the Guess Who's case. Ergo, no one is interested in hearing new Guess Who songs - and you won't hear any tonight.

"No, in fact, we have to leave out about eight or 10 songs that people want to hear," Bachman says.

"We have enough hits to go out and play this voluminous amount of material that everyone recognizes - that's our focus."

When old bands insist on bulking up their shows with new songs, he goes on, the tours tend to bomb. Recent offenders: Supertramp and Jefferson Airplane.

As Bachman puts it, "When I pay my $50 and stand in line, which I do, and park and get in line like cattle to get in that door to see Neil Young, I do not want to hear eight songs he wrote last week. I want to hear Cinnamon Girl, Down by the River, Old Man."

This is not to say there's a rule against old bands recording new songs. Shortly before the Guess Who reunited at the 1999 Pan-Am Games in Winnipeg - a "one-off" that turned into a reunion tour which turned into the present full-blown American Woman world tour - Bachman was mulling over his future. He decided to learn how to be a songwriter, funny as that sounds from Mr. Hit Machine. He went to Nashville to learn how to write country songs and to London to learn the latest pop tricks. He claims he's written more than 100 songs in the last three years, and was planning a behind-the-scenes life in production and artist development when the Guess Who reunion beckoned.

He and Cummings probably have enough material for a new triple-CD set of Guess Who songs, he says, but there's no point yet. "It's like going out and buying a suit for a wedding and you haven't even met the girl yet."

When the time comes, "We'll be ready. I think I'm a way better songwriter than I was way back then. All the studying and the writing I've done, I can't help but be better. I'm going to bring that to the table and Burton's going to bring his rebellion. He hates the Nashville songwriting scene. I love it. So we'll get together and there'll be this push and pull and tug and shove and something really good will come out of it. That's what we did before. I was the more conservative guy and he was the young teenage rebel. Together, it was like a McCartney-Lennon. We temper each other's extremities."

No signs of the old animosity, either.

"Things are much different than they were in the old days. We're older, wiser. We realize that each other is not such a jerk as we thought. It's what you realize about your own father. Five or 10 years after you leave home, you realize, 'He was just a guy like me, he was trying his best, and maybe I was a jerk, too.' "

So Bachman says it doesn't matter if people perceive the Guess Who in 2001 as being on the permanent reunion tour.

He waxes heroic, "You could call it a reunion, you could call it a resumption, you could call it a bunch of guys saying: forget all our stupid, petty differences, our music is suddenly appreciated by everybody everywhere and isn't it amazing that all these songs we wrote when we were kids are now becoming anthemic songs. So let's go and celebrate. We're alive, we can rock and this a moment in time we never, ever thought would come. Let's go and live it to the fullest.

"We do that every day. Before every show, we shake hands and hug each other and say, 'I'm glad to be here.' God has blessed us."

Tickets to the Guess Who with Joe Cocker are $69.50, $55.50 or $39.50, on sale at Ticketmaster (451-8000).