ToneShaper Wiring Kit, Gibson ES-335

Thanks for the great review Richard! Unfortunately, 335-style guitars are all over the map in terms of access to the control cavity. Many of these cavities are accessed from a hole under the bridge pickup - our experience is that most guitars of this style have some sort of access here, the controls are generally not expected to be inserted through the F-holes. Removing the bridge pickup will reveal any access the manufacturer has created.

But the access here varies quite a bit. We've seen guitars where the hole into the cavity is the same size as the bridge pickup itself, making it very easy to slip an entire control harness into the cavity. But we've also see guitars (an Epiphone Sheraton II comes to mind) where the access hole - while provided - was too small to admit even a single CTS pot, and it wasn't an easy hole to enlarge. In the case of the Sheraton the hole was slightly less than an inch square, so it didn't need to be enlarged that much. But it extended at a right angle from the bridge pickup cavity, towards the treble bout of the guitar, and it was nearly impossible to get at it with anything other than files or a rasp.

So every guitar will vary. Have a look under the bridge pickup, in most cases we think you'll find that you have some access to the control cavity, whether clear access or limited access. Either case would provide better access than the F-holes.