Newbie question regarding strings/tuning

[Keith Bowns]

Maybe a dumb question ?
My Stratocaster has a locking nut. Without this, if you use the whammy bar, it will go out of tune.
The locking nut keeps everything perfectly in tune no matter how much you bend the strings.
What prevents a PSG from going out of tune when pedals & KL are utilized?
Thanks

[Bill L. Wilson]

The changer on a steel guitar, is basically taking the place of the locking nut. The strings are locked on the bridge end, instead of the nut end. Once the strings are stretched to pitch, you're good to go. I can wank my Strat w/a Floyd Rose, till the cows come home, and it will not go out of tune. I can tune my Emmons before a show, and it stays in tune all night.

[Pete Burak]

There is a small amount of detuning on a keyed guitar that is analogous to the whammy bar detuning issue.
For example, When you lower string-4 E to Eb on a keyed Steel, some amount of the string goes over the roller-nut to the keyhead side.
When you release the lower-lever, not all of the string comes back over the the roller-nut, and if you check on a tuner, it now appears to be sharp.
As soon as you hit the E to F raise lever and release it, it is back to E.
In the case of Pedal Steel, the string deflection is typically half or whole steps, and is self-correcting as you play by raising/lowering very precicely, so the out of tune-ness is not as drastic as a dive-bomb whammy-bar lick.
On a keyless guitar, this issue, typically reffered to as "Hysterisis, is pretty much eliminated, as there is little to no string on the left side of the roller-nut. Some Keyless brand/models, like GFI, don't even use a roller-nut, the strings just go over a bar.

[Donny Hinson]

Rollers.