I have one guitar with Sperzel Trim-lok locking tuners (Parker DF524). I love it.
They work differently from most others. No lock on the bridge or nut, it's all done at the machine head. Less than one wind of string on the post and a thumb screw behind the tuner to hold the string. You simply put the string in the hole, finger tighten the lock, and tune. The string never overlaps itself. Without multiple windings of strings, there is less give/take/binding of the strings wound on the post.
From Sperzel:This is the ultimate in tuning keys. The locking feature eliminates the need for multiple string wraps, and trem users no longer need a locking nut that deadens string sustain and all annoying Allen screws and wrenches (added weight).
My Parker is the only guitar I have with a whammy bar. The string path is straight from the Sperzel tuners to the ball end of the string at the whammy/stop mechanism (with the exception of the tilt of the headstock). It also has a Graph-Tech nut.
The Parker holds it's tune much better than my Gibson, Epiphone and LTD, and it is the only one I have with a whammy.
If I didn't have to re-drill holes, I'd put Sperzels on all my guitars.
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