Electro Harmonix Synth9 Synthesizer Machine

I have tried many guitar to synth effects/emulators. Most of them use MIDI conversion and have horrible tracking or ghosting effects. The EHX Synth9 does the job properly: good tracking and no (not noticeable anyway) ghosting. I only notice that with program 4 (I think), the synth volume does not work properly: i.e. turning down the synth volume does not stop the effect. Like I said, that glitch is only with program 4, all other programs work properly.

Tried on bass: it works even on the low E string. Although, I think it sounds better on a guitar. Not sure why, personal preference I think.