Trouble with pedalboard - buzzzzzzzzz

[Revok]

Hello Hive Mind, 

 

I need some help / advice regarding my pedal board. During lockdown in 2020 I decided to upgrade my old board and add in a few new pedals, namely the envelope filter, compressor and mono synth. I also upgraded the power supply to the fuel tank.

 

It sounded fine to begin with, but when I was listening through headphones I could hear a distinct 'hum' coming from somewhere - not particularly noticeable when listening just through the amp. 

 

I took my bass (a Sire U5) to a Luthier who checked all the connections and put shielding inside the cavities.... still no luck! 

 

I then changed the power supply to the 1-spot and disconnected all the pedals other than the essential ones which worked for a while until a gig this weekend when....... the buzzing came back. It wasn't there when I was touched the strings but otherwise..... yep you guessed it.......it was sounding like a swarm of p*ssed off wasps.

 

I really don't know what the issue is - whether its a specific pedal, a grounding issue or an electrical supply issue. I was fuming at the weekend at the gig and if i'm honest, it felt really amateurish with me apologising for the umpteenth time to band mates with "sorry about the buzzing, that's me again".

 

I don't quite know where to go with this one - any ideas or suggestions would be greatly appreciated! Pedalboard pic attached 

 

thanks

 

[cheddatom]

If the buzzing goes away when you touch the strings, that'd normally be a grounding issue on the bass wouldn't it? I guess it's always there, but when using your pedals, or just turned up to gig volume, it becomes particularly noticeable. 

[Revok]

yeah I thought it was a grounding issue too - it seemed to be ok when i first got the guitar back from the guy who did the shielding and checked the connections, but the problem seems to be i don't know when or where it will happen - so you can't plan for it.

[Downunderwonder]

Put it all back how it was before the upgrade. See if the noise goes away. Then you can troubleshoot one thing at a time.

 

One time I added some new pedals and an old pedal started to be noisy when it was on, even when the newbiea were off. Some pedals just don't like other pedals.

 

It was suggested to me that I needed a proper isolated power supply for each but I never found one that worked as advertised.

 

The old pedal lost instead as the new one that turned out to be the secret agitator was so sexy and there were plenty of alternatives for the old one.

 

Put it all back as it was before and change one thing at a time.

[A.G.E.N.T.E.]

IME, using a isolated power supply is mandatory. My pedalboard runs smoothly except when I add some digital effects using a non isolated psu. I'd try to test removing pedals one by one to see if the noise comes from a particular pedal. 

[garyt]

Try and identify the source.

if you have 2 basses, try this sequence

with both basses.

Clean bass first, bass direct to amp. Is that OK? 

Then try one pedal at a time to see if you have an offending pedal.

Then start with one pedal, and introduce one pedal at a time, until you hear the noise.  When you hear it, take that pedal out and see if it clears. 

Its a bit of trial and error, but easy way to fault find.  Could even be a lead or connection. 

Once you have found the problem, and sorted it, housekeeping helps.  Check every cable, every connection.  Tidy up your routing.  Spray the connections with some Deoxit. 
It doesn’t look like your PSUs are overloaded, and Daisy chaining shouldn’t be a problem, but isolated power supplies do eradicate any potential hum caused by Daisy chaining. 

[Downunderwonder]

1 hour ago, garyt said:

Try and identify the source.

if you have 2 basses, try this sequence

with both basses.

Clean bass first, bass direct to amp. Is that OK? 

Then try one pedal at a time to see if you have an offending pedal.

Then start with one pedal, and introduce one pedal at a time, until you hear the noise.  When you hear it, take that pedal out and see if it clears. 

Its a bit of trial and error, but easy way to fault find.  Could even be a lead or connection. 

Once you have found the problem, and sorted it, housekeeping helps.  Check every cable, every connection.  Tidy up your routing.  Spray the connections with some Deoxit. 
It doesn’t look like your PSUs are overloaded, and Daisy chaining shouldn’t be a problem, but isolated power supplies do eradicate any potential hum caused by Daisy chaining. 

See my experience above. The test one thing at a time thing is a good general rule but it doesn't catch all.

[rmorris]

On 10/05/2022 at 09:00, A.G.E.N.T.E. said:

IME, using a isolated power supply is mandatory. My pedalboard runs smoothly except when I add some digital effects using a non isolated psu. I'd try to test removing pedals one by one to see if the noise comes from a particular pedal. 

 

Top advice in general. But not the issue here where touching the strings / metalwork makes the noise go away.

[rmorris]

On 09/05/2022 at 13:59, cheddatom said:

If the buzzing goes away when you touch the strings, that'd normally be a grounding issue on the bass wouldn't it? I guess it's always there, but when using your pedals, or just turned up to gig volume, it becomes particularly noticeable. 

 

The noise going away indicates that the bass itself IS 'grounded'. But the screening of control cavities etc may not be good enough. A pedal with gain may amplify (literally) the problem.

Another possibility is a break in the cable screens or power grounds. It will still 'work' but is likely to be more susceptible to induced noise.

[Downunderwonder]

4 hours ago, rmorris said:

 

The noise going away indicates that the bass itself IS 'grounded'. But the screening of control cavities etc may not be good enough. A pedal with gain may amplify (literally) the problem.

Another possibility is a break in the cable screens or power grounds. It will still 'work' but is likely to be more susceptible to induced noise.

The takeaway I got from the last time around this mulberry bush is it's semantics. The bridge grounding grounds the player from acting as some giant inductive antenna.

[rmorris]

2 hours ago, Downunderwonder said:

The takeaway I got from the last time around this mulberry bush is it's semantics. The bridge grounding grounds the player from acting as some giant inductive antenna.

 

Basically yes. Same sort of thing as when you can get better radio reception by putting your hand near the aerial.