-
The logo is preatty cool but is too much sophisticated and with wrong dimension.
You need to work on composing the logo better with just the element you have. The guitar is too high you will find a lot of problem placing it in other design, on a t-shirt etc. And then in my mind you should try to have less color. Try to make this on black background and then try to invert it on white background. Use 2 color. Or at least try.

thanks for your advices... the guitar has now gone from my concept as the client don't like. I kept the s with a socket cable idea and I made the logo more dry. It will still need some tweeking but I like it more than the original concept