What is this effect??

At the very beginning of the Stevie Ray Vaughan song Couldn't Stand the Weather, Stevie uses this effect that I'm dying to know what it's called. He uses it in the intro and also on the lead guitar throughout the song. Does anyone know what it is? Is it a pedal effect or is it from an amp setting or what? Listen to the lead guitar especially in the intro and please someone tell me what that's called. There are many other songs on which SRV did it, but I know for sure it's in this one. Tin Pan Alley is another one. Can anyone help me?

[This message has been edited by BarryS (edited 09-26-2000).]

I'm not 100% sure, but my best guess is that effect is either a Tremelo pedal, or possibly he's playing through a Leslie cabinet.
If you're not familiar with Tremelos, they're pretty easy to learn to use. The function basically like a Chorus pedal on steroids. I've got one by DOD that sounds great, especially when playing a Strat set up semi-clean with the neck pickup. I think Stevie's choice was a Roto-Vibe pedal ... but I may be wrong.
You can pick a Tremelo pedal up for under a $100.00 and play around and experiment to get that "Stevie" sound ......

Leslie cabs are sweeeeet... kinda hard to find one with a rotary thats fully working... i know a guy that plays a Korg M1 thru one... talk about sweet sounding.

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