Would taking the preamp out of my bass solve my hissing issue?

[Dr. Turkey]

tl;dr: My 6 string started hissing recently and I'm not sure why, since the pickups are passive and I almost never mess with the onboard eq I'm wondering if just taking the preamp out would make my life easier.

So about 9 years ago (damn) I got a schecter stilleto 6 for dumb reasons (I wanted a low f# to match my 8 string guitar) and modded the hell out of it for dumber reasons (I had a habit of impulsively stuffing unnecessary crap into instruments just for the sake of making changes). I took out the EMGHZ pickups and preamp, had it routed for a music man PU with a series/parallel switch in the bridge, a P PU in the middle and a nordstrand DC 6 in the neck connected to a varitone switch (useless in 2 positions), and had an aguilar 3 band eq installed in place of the emg preamp.

Not too long ago I found one of the batteries corroded so I switched them both out, and even more recently I switched the strings to labella gold flats and for some reason it was very shortly after the string change that the hissing started. It's less noticeable on bridge pickup when it's switched to parallel and practically not there at all on the neck but when the bridge is in series it's pretty bad and even worse on the middle pickup. It goes away as I turn down the treble nob but that obviously changes my sound. Dialing the eq on my amp doesn't seem to affect it as much for some reason.

Anyway, since I typically keep the eq knobs in the neutral position anyway, would taking the preamp out and just making it fully passive solve my problems, or is there something else I should trouble shoot first?

 

[eniac]

Sure does sound like the preamp, assuming no wiring inside the control cavity has been disturbed.

A side note: Hiss can sometimes be a symptom of preamp oscillation. And if that's happening, the cause could be a component inside the Aguilar preamp has drifted. But those things are potted, right? If so, can't troubleshoot it anyway, so.....

Yes, I would pull the preamp out of there if you're not using its EQ. Just remember that the instrument's pickups will lose their buffering, and may sound a bit less crisp into a relatively low impedance load like a passive DI. Into a typical amp, though, I'd expect little to no change.

 

[tom-g]

Before taking out the preamp, I‘d try to find the reason it is hissing which it did not do before.

 

[mambo4]

Corrosion on batteries can sometimes crossover onto the electronic components that the battery is attached to. I would check the connections of the batteries to make sure that corrosion is not also on the receiving end. toothbrush and vinegar can clean up corrosion on small electronic components.

 

[newfuture]

I don't know if the preamp is causing the issue, but I think the solution is clear. You need more pickups in that thing!

 

[_One//Man//Mutiny_]

Do also happen to have a Nordstrom’s Acinonyx, it may be jealous.

Joking aside, interesting that the battery was corroded and also the string change made it worse. Looks like a solid bass plate on the bridge but did you have to make any set up adjustments? Or have someone else do it? Maybe something was done to make the ground wire for the bridge come loose.

 

[Five or Six]

How long was that wonky battery in there?

 

[smurfco]

Just to make sure - hiss or hum?

 

[lowplaces]

Try a different cable yet ? Try it into another amp ?

 

[tpaul]

I would try removing the snakes first.

 

[eniac]

Just to make sure - hiss or hum?

I sure hope it's hiss, because he said it goes away when he turns the preamp treble down. If it is hum and it actually goes away when the treble is turned down, then there's something truly satanic going on and I don't want any part of it!

 

[Topkat13]

If you're hissing I would start with and Ear, Nose and Throat specialist.

 

[Element Zero]

One of my basses had some weird hiss that started when I tried a set of LaBella White Nylon strings. Went away once I switched back to normal strings.

 

[Dr. Turkey]

How long was that wonky battery in there?

Embarrassingly, I can't say for sure. For a variety of personal reasons, until recently, I hardly got a chance to touch my instruments in the past 5 years so I didn't catch it until some months ago

Just to make sure - hiss or hum?

Definitely hiss, distinctly different from my my single coils.

Try a different cable yet ? Try it into another amp

Yeah to both, tried getting further away from power outlets/strips too

One of my basses had some weird hiss that started when I tried a set of LaBella White Nylon strings. Went away once I switched back to normal strings.

That's unfortunate. I really like these strings, I haven't heard about anything like this happening

Sure does sound like the preamp, assuming no wiring inside the control cavity has been disturbed.

A side note: Hiss can sometimes be a symptom of preamp oscillation. And if that's happening, the cause could be a component inside the Aguilar preamp has drifted. But those things are potted, right? If so, can't troubleshoot it anyway, so.....

Yes, I would pull the preamp out of there if you're not using its EQ. Just remember that the instrument's pickups will lose their buffering, and may sound a bit less crisp into a relatively low impedance load like a passive DI. Into a typical amp, though, I'd expect little to no change.

That's good to know. I've never played a Music Man style pickup without a preamp so I wasn't sure if it was an important part of the sound. I guess my best choice is to take it to an expert and hope they can sort it out.

Corrosion on batteries can sometimes crossover onto the electronic components that the battery is attached to. I would check the connections of the batteries to make sure that corrosion is not also on the receiving end. toothbrush and vinegar can clean up corrosion on small electronic components.

I was worried about this too when I saw the battery but I checked the cavities and connectors and didn't see anything. Wouldn't hurt to take another look I guess

 

[J Wilson]

Only worth it if it does it with several known good guitar cables into an amp or amps that don't hiss with a different bass.

In other words, troubleshoot everything in the signal chain, prove it's a problem in that bass before heading into surgery.

 

[newfuture]

One of my basses had some weird hiss that started when I tried a set of LaBella White Nylon strings. Went away once I switched back to normal strings.

Had a similar issue with fender tape wounds and Roto88 (also tapes). It was due to the tape also being an insulator and preventing my fingers connecting to ground.

 

[Dr. Turkey]

That might explain why it's not as prominent when I have my hands on the strings... These aren't tape wound but maybe the copper alloy is causing an issue? Was this happening with an active bass?