Semi Acoustic pickup gurgling sound...

seachto7

Another techie question. I seem to have this intermittent problem with my pickup. It's a Fishman prefix pro, and when I play a chord or note, I sometimes get a gurgling sound "behind" the note or chord. I can hear the note or chord I've played but it's accompanied by a gurgling type sound as well.
I've changed the battery, had the wiring checked etc. I'm not sure what it could be and the fact it only happens from time to time is baffling. Any ideas?

spoonbadger

seachto7 wrote: »

Another techie question. I seem to have this intermittent problem with my pickup. It's a Fishman prefix pro, and when I play a chord or note, I sometimes get a gurgling sound "behind" the note or chord. I can hear the note or chord I've played but it's accompanied by a gurgling type sound as well.
I've changed the battery, had the wiring checked etc. I'm not sure what it could be and the fact it only happens from time to time is baffling. Any ideas?

Well lets start by ruling out the obvious...

1. Could it be fret noise?.
2. Could it be buzzing in the nut/saddle?.
3. Do you hear anything similiar when playing unplugged?.
4. Has it been exposed to temperature/climate changes recently?

Next...

1. It's a fishman, so i'm guessing it's a piezo?.
2. Does it happen less if the pickup volume is turned down?.
3. Do you get a similar sound by tapping/knocking on the guitar body/bridge/pickup?.
4. Is the pickup loose in any way?.
5. Does it happen on certain notes/chords/strings more than others?.

seachto7

howdee,

ok, i can answer some of those Q's straight off. When it happens, it is usually on the lower notes, if I fret the 7th fret on the A string, you hear it, sometimes if I strum a C chord it's fairly noticeable, the higher up the fretboard I go, the less it sounds. It doesn't happen unplugged at all. I would only really notice it in a quiet situation with the guitar plugged in. Tapping the pup doesn't do anything and it hasn't been exposed to extreme temp changes. Out of curiosity, how would that affect it?

My gut tells me it could well be the saddle, but again, unplugged it's hard to tell.

The pup is't loose either...

Eoin Madsen

Battery would have been my first guess. Next guess would be a component failure in the preamp, but I wouldn't rule out the pickup itself without knowing more. Intermittent faults are usually degenerative in any case, so I'd be thinking about replacing some parts.

seachto7

http://www.dguitarparts.com/images/fPrefixOnBlender.jpg

This is the pup I have in the guitar. I'm not sure about replacing it...yeearrrrghhh....:o

Doctor J

Can you record the noise? You should be able to run a signal from your guitar into a PC.

Fingers Mcginty

If you have the blend slide all the way to the left so that mic only is selected do you still get the strange noise...and likewise with the slider to the piezo position?????

spoonbadger

seachto7 wrote: »

howdee,

ok, i can answer some of those Q's straight off. When it happens, it is usually on the lower notes, if I fret the 7th fret on the A string, you hear it, sometimes if I strum a C chord it's fairly noticeable, the higher up the fretboard I go, the less it sounds. It doesn't happen unplugged at all. I would only really notice it in a quiet situation with the guitar plugged in. Tapping the pup doesn't do anything and it hasn't been exposed to extreme temp changes. Out of curiosity, how would that affect it?

My gut tells me it could well be the saddle, but again, unplugged it's hard to tell.

The pup is't loose either...

Well, if it happened while tapping the pup/top, it might suggest that the pup assembly is loose/rattling. It could also suggest some form of microphonics, but that's considered an important part of piezo pickup .

Temperature change could result in shrinking/expanding, which can lead to fret noise or internal buzzing.

If it doesn't happen when the guitar is unplugged, this kinda rules out fret/saddle/nut noise. But since piezo pickups have a nasty habit of picking up *every* little vibration, it might still come down to some kind of buzzing.

Fingers Mcginty wrote: »

If you have the blend slide all the way to the left so that mic only is selected do you still get the strange noise...and likewise with the slider to the piezo position?????

This is actually very helpful!. Good thinking fingers .

And like the good Doc. said, get us some sound clips.

seachto7

i'll get some sound clips up later hopefully..cheers folks

seachto7

shame on me folks. I posted the wrong pickup pics..

http://www.fishman.com/uploads/products/images/39.jpg

it's the Prefix Plus, so no blender on it. I was thinking earlier "have I got a blender really...??"

anyways, I plugged it in, recorded something, and I've got a loud hum in the background. I think I must have left it down while the lead was plugged in the other day. The jack input is at the back, and maybe something is loose in there. So , once I get that sorted, the gurgling sound is the next thing. You can still kind of hear it, but the hum is drowning it out, so no point posting sound clips on here just yet. It is more noticeable through a speaker for some reason...Does that make sense? Or maybe it's just me convincing myself...