[briggleman]

I will add my 2 cents worth of "experience" opinion.

If you have the ES version 1.0, 1.1 and 1.2 (more so with version 1.1, 3 volt, 2 SB transducers and 1.1, 9 volt, 2 SB transducers) the K4 is the way to go to fully realize the full potential and allow effects boxes into your guitar playing. Version 1.2 had a redesigned pre-amp and only 1 SB transducer. All ES version 1 systems (all versions) also utilize a mag. pickup at the neck body position. ES version 2.0 does not use the mag. pickup and is a vertical piezo system designed by Taylor placed at the bridge.

If you have the latest version which most have dubbed version 2.0, then no, I do not think it is a worthy investment.

Version 1 ES iteration through all its forms was a balanced system. The K4 was made for that. ES Version 2 is an un-balanced preamp found in most all other brand systems and therefore the K4 is way overkill for tweaking your EQ and adding effects.

My recommendation if you have a version of the ES 1 series, go with the Pigtronix Keymaster. Its Cheaper, allows the use of effects, and keeps the signal, impedance issues at a non-think about level. ES version 2 will work with every EQ system out there so think bang for the buck with version 2.

Brad