Schecter Stiletto Stealth 4 - Hum and pickups grabbing body noise?

[bitzie]

I just got a new Schecter Stiletto Stealth 4 and love it so far. The weight, balance, and neck are all pretty much perfect for me.

I do have a couple issues though. When I first got it, there was some electrical hum which would go away if I touched the strings or the control knobs. If I touched the screws for the neck pickup, the hum would get worse. To get the protective plastic off the pickguard, I totally unscrewed it, took the plastic off, and just had a look in the control cavity to see if anything looked off. Nothing did, but when I put the guard back on, the hum was pretty much gone. Except for the bridge pickup which is extremely noisy. The neck pickup is fine, which for now works great because I like the tone from the neck pup more.

I've also noticed that the pups are picking up a ton of noise from the body of the guitar. I am only practising in headphones for now and if I lightly tap the body of the bass I can hear that amplified in the headphones. Even the creaking of my strap gets picked up.

Now I've heard that the electronics in Schecters can be pretty crap which seems to be the case here. I'm assuming that the hum problems stem from a grounding issue somewhere. Is the pickups amplifying body noise typical of active pickups or is it just the sub-par electronics? I had an Ibanez SR505 years ago and don't remember issues like this.

I am considering swapping over to a fully passive setup as I do love the sound of my P-bass, but my shoulder just can't take the weight anymore. So that would probably be one solution, but I'm just wondering if there's anything I can do in the meantime to deal with the hum and extraneous noise.

 

[dwizum]

The hum you are describing sounds like a classic indicator of bad shielding. When you fiddled with the pickguard and "fixed" it, you may have inadvertently changed something that impacted the shielding. I'm not familiar with that model of bass or how it's shielded so it's hard to say more without seeing photos at least. If you want to fix the pickup that's still humming you could try shielding it's cavity.

A pickup amplifying acoustic noise like you're describing is called a "microphonic" pickup. Basically the noises are causing the windings inside the pickup to vibrate in a way which creates a signal that gets sent to your amp. This is an unintentional phenomenon, your pickups are only "supposed" to pick up the magnetic signal from your vibrating strings. Ironically, early electric guitar pickup enthusiasts sometimes get excited about a microphonic pickup (you can talk into the pickups of some early guitars as if you're talking into a microphone) but practically speaking it's not a good thing. You can consider wax potting the pickups if they're not potted, or just replace them with something higher quality.

 

[bitzie]

Thanks dwizum! It looks like its just conductive paint in the cavity so I might look into beefing that up with some copper tape. As for the pickups themselves, I contacted a local luthier to see how much they would charge to convert it over to passive, but I'll also look into what it would entail to actually do it myself.