The SR500EPB Saga Continues

In the last episode of The SR500EPB Saga we discovered that Tim purchased a used Ibanez SR500EPB from Reverb, and it arrived in less than professionally setup shape. He sent it off to Guitar Center for a Platinum Setup Service, and it returned in less than professionally setup shape. So, with a little bit of research he set it up himself and was happy with the results.

Now, on to today’s episode!

So, I was never really happy with the sound of this bass, and with some experimenting over the weekend I realized that the mids on the bass were dead. It wasn’t putting any mids out. I’d turn down everything on the EQ but the treble, pluck a note, and hear it. Do the same with the bass, I’d hear it. Do the same with the mids, almost no sound came out. So I popped out the pickups, opened up the electronics cavity, and did some snooping. I discovered that one of the mini solderless terminals was plugged in at an angle, so that only one side was making connection. I plugged it in completely, and viola! The mids passed the EQ test I described above, and the bass sounds great now.

Except for one thing, and this has been happening ever since I got it: if I sit too close to my PC, I pick up a bunch of interference through (I think) the pickups. I don’t seem to get it from anywhere else but the PC; I’m sitting under neon lights, right next to a little refrigerator and an air purifier, but it’s only when it’s close to the PC that I’m picking up… well, honestly it almost sounds like a broken up modem tone.

This leads me to believe it’s a shielding problem. While I took a year of ITT Technical Institute and am no dummy when it comes to electronics, I’ve no idea how to troubleshoot a shielding issue in an electric stringed instrument… assuming it is, in fact, a shielding issue. It’s not a grounding issue, that I’m sure of.

Any thoughts or ideas on what to look for or how to insure it’s properly shielded?



I’m no expert either, but what I do know is that all shielding parts need to be connected. So, if the cavity is lined with copper tape, each piece of tape needs to be connected to the other ones. I think people punch little holes in the parts that overlap to create the connection. Of course, if your bass has a pick guard that is shielded on the inside, that shielding needs to connect to the cavity shielding as well.


In my opinon you are dealing with another broken wire or some sort of bad contact. Shielding needs a proper ground to work. To start t/s I would suggest to remove the battery and check resistance of the wiring with an ohm meter first. Wire for wire from point to point.
If ok, you can plug an instrument cable and messure the resistance of the whole electric system (still w/o battery!) . In passive mode resistance should be some 10k Ohm but not much more. If the resistance is significantly higher, it points to an open connection or cold solder joint. An open circuit may make the shielding work like an antenna.
Moving or tapping at the wiring and solder points while a ohm meter is connected to the instrument cable can help to locate your troublemaker.
Hope that helps…


Yes, start with insuring bridge and other grounds are all properly connected.
Then worry about shielding.
PCs generate a TON of noise, esp USB cables.
Take a step back or move your PC/USB cables if you can, mine are under my desk.


Just for sh!ts and giggles, when you are near the PC disable all wifi and bluetooth communication to see if this alters the interference at all. And if its a laptop unplug it from the wall and run it on battery only.

I had a similar problem with a bass plugged into a BOSS GT-1B plugged into a laptop. When I removed the ground path the problem disappeared.

Another guess is the preamp is faulty.


Thanks, everyone, for the replies. But… I don’t think this is an actual problem any more. At least… not solely with the SR500EPB.

I just tried each of my other basses (Ibanez SR300, Carvin LB20) within a foot or two of the PC, and they’re ALL picking up the same noise. I guess I just never noticed on the other basses, I guess the SR500EPB is just a bit more sensitive to it than the others. Or maybe I was listening with a more critical ear because of the other issues with the SR500EPB.

So… yeah. Huh.

1 Like

I noticed a light hum but only if my laptop was plugged into power. Running off battery the hum is gone. Running a MacAir with no wired connection to Yamaha 504/Fender Rumble. Stepping a foot or two further away from the dreaded power cord also solved the problem (but then Josh was far away…)

1 Like

Hopefully it’ll all work out for you and you find the joy you want in the bass you wanted.

1 Like

This is not unusual. My PC generates a ton of EM output too, and basses can pick it up and amplify it. Switching to passive mode sometimes helps a little.

It’s happened across all my basses and also happened to my guitar. PC’s can simply be extremely noisy in the EM spectrum.

It can often be the cabling as others have mentioned as well.

1 Like