Hum from pedalboard

[Linus27]

I seem to be getting an earthing hum from my pedalboard. I’m using a new Harley Benton ISO power supply which included the Euro plug and Uk adaptor. I’m using the power cables that came with it and patch leads that I bought separately.

 

The thing is, it doesn’t always do it, only at certain venues and when I touch my strings it stops. I’ve also tried different basses and no difference.

 

is there anything I can do to eliminate this? Anything I can plug in that will cancel the hum or is it a case of buying a better power supply.

 

Edited February 2 by Linus27

[Downunderwonder]

A hum that goes away when you ground the bass sounds like the first pedal and the basses have different grounds. No ground on your basses?

[uk_lefty]

12 hours ago, Linus27 said:

I seem to be getting an earthing hum from my pedalboard. I’m using a new Harley Benton ISO power supply which included the Euro plug and Uk adaptor. I’m using the power cables that came with it and patch leads that I bought separately.

 

The thing is, it doesn’t always do it, only at certain venues and when I touch my strings it stops. I’ve also tried different basses and no difference.

 

is there anything I can do to eliminate this? Anything I can plug in that will cancel the hum or is it a case of buying a better power supply.

 

I've got the same power block and use the EU-UK adaptor. Hum is quite rare, even in rooms with lots of interference.

[Skybone]

Maybe try a different plug adaptor, with a view to changing the plug to a UK one?

[sandy_r]

13 hours ago, Linus27 said:

I seem to be getting an earthing hum from my pedalboard. I’m using a new Harley Benton ISO power supply which included the Euro plug and Uk adaptor. I’m using the power cables that came with it and patch leads that I bought separately.

The thing is, it doesn’t always do it, only at certain venues and when I touch my strings it stops. I’ve also tried different basses and no difference.

is there anything I can do to eliminate this? Anything I can plug in that will cancel the hum or is it a case of buying a better power supply.

 

 

The PSU, in common with most small(ish) domestic adaptors, will be double-insulated for protection, not earthed - So the effective shielding of the pedalboard gear is entirely reliant on good earth continuity all through the pedal chain from Amp to Bass

 

If hum is only noticeable in some locations (but with all basses), then you need to do some more checking at one of the locations/venues where hum is an issue

 

If hum present with guitar direct to amp, try different amp

- still hum? Suspect ground connection at location

 - no hum on 2nd amp, Suspect ground connection in 1st amp

 

If hum present with pedal board powered up and all pedals switched to bypass

 - Suspect ground continuity on pedal board chain. Disconnect all in chain and add 1 pedal (and its patch) at a time

    - if hum follows pedal addition, remove pedal (and its patch) again. Add next in chain. Rinse & repeat

 

Check jack sockets & plugs on any suspect pedal/patch links, for rust/corrosion/damage

 

HTH

 

 

Edited February 3 by sandy_r

[Linus27]

Thanks everyone, will try all the suggestions. Just to confirm, with bass plugged direct into the amp, there was no hum. Back through the pedalboard and hum returned. I also got time to disconnect the Mooer Reverb and Bass Sweeper but the hum was still there so I'll try the others next time.

[BigRedX]

I see you have a thin lead going to the PSU distribution.

 

What is on the other end of that? A "wall-wart"? A transformer block with a mains lead? Captive or on an IEC socket? Might be worth taking a photo of this including the UK adaptor so we can advise further.

 

[Bassmidget209]

I have the same power supply and I have the zoom ms60b. There is a good chance that's your problem. Was with me anyways. The zooms are apparently very picky with their power source. You can get a wee power conditioner from Palmer that fits under your board. Run that between the power supply and the zoom and that could solve (some) of your problems. 

 

I have had zero issues with hum since I did that. The conditioner was just over 20 quid from memory 

[Linus27]

4 hours ago, BigRedX said:

I see you have a thin lead going to the PSU distribution.

 

What is on the other end of that? A "wall-wart"? A transformer block with a mains lead? Captive or on an IEC socket? Might be worth taking a photo of this including the UK adaptor so we can advise further.

 

 

@BigRedX This is the cable. It's the main lead with Euro plug that came with the power supply and uk adaptor that also comes with the power supply. When you purchase this power supply they always supply the UK adaptor as well.

 

[Linus27]

2 hours ago, Bassmidget209 said:

I have the same power supply and I have the zoom ms60b. There is a good chance that's your problem. Was with me anyways. The zooms are apparently very picky with their power source. You can get a wee power conditioner from Palmer that fits under your board. Run that between the power supply and the zoom and that could solve (some) of your problems. 

 

I have had zero issues with hum since I did that. The conditioner was just over 20 quid from memory 

 

That's quite interesting as I only use the Zoom MS60b for the Opto Compressor but this week I purchased an Ampeg Opto Compressor to replace it which actually arrived this morning. So I will be replacing the MS60b from now on so it will be interesting to see if the hum stays away or not.

[BigRedX]

@Linus27 Thanks for that photo. Does the UK adapter fit over the pins of the Euro Power supply or does it plug in?

 

If it's the later then they are breaking UK trading standards as any electrical equipment supplied for to the UK must come either with leads with UK plugs or adapters that fit over the Euro-style plug and cannot be removed without undoing screws. Plug-in adapters are no longer allowed, and in that case the PSU should be replaced with one with a built-in UK plug.

[Linus27]

21 minutes ago, BigRedX said:

@Linus27 Thanks for that photo. Does the UK adapter fit over the pins of the Euro Power supply or does it plug in?

 

If it's the later then they are breaking UK trading standards as any electrical equipment supplied for to the UK must come either with leads with UK plugs or adapters that fit over the Euro-style plug and cannot be removed without undoing screws. Plug-in adapters are no longer allowed, and in that case the PSU should be replaced with one with a built-in UK plug.

 

It plugs in. You plug the Euro plug into the UK adaptor, sliding the two pins into the UK adaptor.

 

[BigRedX]

17 hours ago, Linus27 said:

That's nasty. My understanding of Trading Standards regulations regarding electrical equipment sold in/to the UK is that if an adaptor is required, it can no longer be of the simple plug-in variety like yours, but must be attached to the Euro plug by some method other than just the electrical connections. Normally for a Euro plug on a lead there is a special UK style plug which clamps over the Euro plug and is held in place by one or more screws. If it is not possible to supply a suitable adaptor, then a PSU with an integral UK mains plug needs to be supplied. I would complain to the vendor citing UK Trading Standards. If enough people complain they might just get the message and start supplying regulation standard plugs as standard.

 

While it may not be contributing to your hum problem this adaptor is another potential point of failure on your gigging equipment. However I have come across similar issues with equipment powered by PSUs with no earth connection on the PSU.

 

Unfortunately, there is no substitute for good old trial and error. Start by removing everything from the pedal board and disconnecting them from the PSU. Then try one pedal at a time. If each one individually produces no hum, then start adding devices one at a time in the order they will be in your final signal chain. I suspect the hum will re-appear when you add you first digital device. 

 

Good luck!

[StingRayBoy42]

Not sure if it'll sort your problem, but I got a replacement adapter for a Harley Benton PSU from myvolts.

It's great and their customer service is fantastic.

[Linus27]

30 minutes ago, StingRayBoy42 said:

Not sure if it'll sort your problem, but I got a replacement adapter for a Harley Benton PSU from myvolts.

It's great and their customer service is fantastic.

 

Brilliant, thank you, have found it on their webpage so will purchase one and a spare.

[StingRayBoy42]

32 minutes ago, Linus27 said:

 

Brilliant, thank you, have found it on their webpage so will purchase one and a spare.

 

Like I say, I can't promise it will sort your problem, but it is definitely less bulky and kickoverable.

 

It comes with a straight-straight polarity reversing adaption which didn't fit under my mini board.

 

When I asked if they sold an angled one, they sent me one for free.

 

Little things like that are why I'm recommending them!

[JapanAxe]

On 03/02/2024 at 16:44, BigRedX said:

@Linus27 Thanks for that photo. Does the UK adapter fit over the pins of the Euro Power supply or does it plug in?

 

If it's the later then they are breaking UK trading standards as any electrical equipment supplied for to the UK must come either with leads with UK plugs or adapters that fit over the Euro-style plug and cannot be removed without undoing screws. Plug-in adapters are no longer allowed, and in that case the PSU should be replaced with one with a built-in UK plug.

Yes, any adaptor should enclose the non-UK plug so that it can’t be accessed without use of a tool (eg a screwdriver to remove a screw). However this is unlikely to be the source of the hum, it’s just a way of connecting the mains in Class II equipment (no safety earth). The problem with 2-pin European plugs is that they look like you can plug them into a shaver socket, but if you do that it puts the pins under stress.

[BigRedX]

17 hours ago, StingRayBoy42 said:

Not sure if it'll sort your problem, but I got a replacement adapter for a Harley Benton PSU from myvolts.

It's great and their customer service is fantastic.

 

16 hours ago, Linus27 said:

 

Brilliant, thank you, have found it on their webpage so will purchase one and a spare.

 

It is really the vendor's duty to sort you out with a proper UK legal PSU. Since it appears to be Harley Benton that's Thomann and they should really know better.

 

While it might be quicker to just go out and buy a replacement PSU, it means that you are out of pocket buying something that should have been supplied in the first place, and it also means that Thomann are less likely to start supplying the correct electrical items for sale to the UK.