I purchased a Morrell 6-String Pro lap steel guitar after the Recording King lap steel I attempted to buy was back-ordered beyond my patience to wait. I am fairly happy with the Morrell guitar, but not entirely so. There was a slight hum when I played the guitar through any of my amps. The noise disappeared when I touched any grounded part of the guitar. Unfortunately, the bridge and strings were not grounded.
There are many sources concerning unwanted hum and grounding to be found on the internet. All agree that the bridge of an electric guitar should be grounded by running a wire from the bridge to the common grounding connection usually on the tone pot. This is in turn wired to the sleeve of the output jack.
Before doing anything drastic, I double checked to see if the bridge was grounded using my ancient, analog VOM (which still works fine for my needs).
I loosened the strings and removed the bridge. There should have been a hole with a ground wire under the bridge. There wasn’t.
There was no hole to the pickup cavity and thus no grounding wire for the bridge. I masked off the position of the bridge before removing it. I have to drill a hole to the pickup cavity from the bridge.
I was most worried about this part of the operation—drilling an angled hole so I could run a grounding wire from under the bridge. The drill bit might slip or I might not have set the angle shallow enough. But, in fact the hole was drilled without problem. I did start by going straight down a small amount before angling towards the PU cavity. That was so the drill bit wouldn’t slide across the surface of the guitar when I started.
I used thin, stranded copper wire for the ground. I pre-tinned the pot connection and the ground going to the pot before making the solder connection. The other end was spread to single strands of copper. The force of the bridge screws makes the connection between the ground wire and the bridge. There is no solder connection on the bridge end.
I used my VOM to check the connection from pot to jack sleeve and from bridge ground wire to jack sleeve before re-assembling the pieces. I checked again after screwing in the bridge, before screwing down the pickup cover. Everything seemed fine.
The final test was to tune up and plug in. This is where I got mixed results. There is still noticeable hum when the amp is on and guitar is just sitting without me touching it. However, as long as my hand is touching the strings or bridge, there is no hum. My hand is almost always touching the strings and/or the bridge when playing the lap steel, so there is almost no hum. But… there is still hum when I’m not touching a grounded part.
Was this worth it? Yes. I haven’t decided whether to dig further into the hum problem since under normal playing conditions it is fine.