What power conditioning/filtering for home?

OnTheHunt

Hello.  At home I run a few amps, a couple of 'wall wart' PSUs for individual pedals and a brick for multiple 9vdc pedals.  When plugging straight into an amp, nice and silent.  When I go via any pedal I get a hum, which I assume to be mains hum.  Doesn't matter whether I'm using the brick PSU, or one of the dedicated PSUs, or going via an extension cable or straight into a mains socket, always the same hum (hence my assumption it's mains and not anything to do with my PSUs/pedals).  So 2 questions:

1.  Why don't I get the same hum when going direct to amp?  Is it something to do with the transformers in the PSUs?  Is it actually 'transformer hum' I'm hearing?  (If there's such a thing!)

2.  What to do about it?  I'm thinking of 2 things....first something like the Furman M-10 LX E for powering things which take IEC connections - amps, monitors, i/o interface etc.  Second, is there an equivalent of the Furman in an extension lead format?  I'm thinking a 'silent' extension cable to plug the brick and my PSUs back into - or in this scenario would I be back to 'transformer hum'?

Also looking at a new brick as I'm conscious the outputs on mine aren't isolated.  That said, I get the same amount of hum with just 1 pedal as I do 6, so I think that's mains again, as opposed to interference between devices.

Any advice greatly appreciated!

sgosden

are you using an amp fx loop?

OnTheHunt

Nay, no fx loop. 

ecc83

Since the 'Mains Supply' is common to all states of the gear it follows that it is not the cause of the hum!

UK mains is very stable, very clean and not prone to 'spikes'. You do NOT need any filters or conditioners on it. IF you have crap on a mains supply it is the DEVICE PRODUCING IT that needs filtering (ever seen the BMthr filters in a MW oven supply?) .

You could have an earth loop, (aka, ground and hum loop) . You might be using more gain than direct into the amp. One common problem is that external 'line lump' PSUs themselves tend to radiate hum quite badly, keep them a mtr away from sensitive kit and leads.

It is a fact of electric guitar life that the things are noisy bstds, prone to picking up hum and other radiated crap. The more gain and gear you put in the signal path, the worse it gets.

Dave.

Rocker

Does the problem go away if you use batteries to power the FX pedals?

OnTheHunt

ecc83 said:

Since the 'Mains Supply' is common to all states of the gear it follows that it is not the cause of the hum!

UK mains is very stable, very clean and not prone to 'spikes'. You do NOT need any filters or conditioners on it. IF you have crap on a mains supply it is the DEVICE PRODUCING IT that needs filtering (ever seen the BMthr filters in a MW oven supply?) .

You could have an earth loop, (aka, ground and hum loop) . You might be using more gain than direct into the amp. One common problem is that external 'line lump' PSUs themselves tend to radiate hum quite badly, keep them a mtr away from sensitive kit and leads.

It is a fact of electric guitar life that the things are noisy bstds, prone to picking up hum and other radiated crap. The more gain and gear you put in the signal path, the worse it gets.

Dave.

It isn't a gain issue, I get the buzz with just a reverb pedal in the chain, regardless of whether it's on or off.  Likewise with OD, exact same buzz regardless of whether pedal is engaged.

Earth/ground/hum loop - how does one address that?

OnTheHunt

Rocker said:

Does the problem go away if you use batteries to power the FX pedals?

It does, yes.  Just but a battery in a Boss pedal, works fine and nice and quiet - soon as you plug the PSU in the buzz is immediate.

lasermonkey

Rocker said:

Does the problem go away if you use batteries to power the FX pedals?

This is definitely worth trying. I've encountered a fair few pedals that have no or poor PSU filtering and this can lead to hum, especially with cheap, switch mode power supplies.

Some digital pedals are extremely picky about power supply too.

OnTheHunt

Just doing a bit more tinkering here and narrowing it down some perhaps.  Delay pedal has a 9vdc centre +ve supply, it is silent.  I have another 9vdc psu with switchable polarity, set it at centre +ve with the delay and it's got that bzzzzzzzz going on... it's this 9vdc supply which normally powers my reverb (9vdc centre -ve), plus it buzzes with other pedals.  So, it certainly looks like that PSU is a culprit.

But, if I power the reverb (or another other 9vdc centre -ve box) from my power brick, I also get the same buzz.  I also have an OD which runs its own 12vdc and it too is silent.  

So could it be both my wall wart 9vdc and brick PSUs are buzzy things which I should swap out?  The fact my delay and OD run silently on their own PSUs, plus silence when guitar direct to amp, confirms mains is fine and it's the PSU end where problems lay - that be right?

Cheers!

UnclePsychosis

You almost certainly just need a proper isolated power supply.

Power bricks and daisy chains and so on can work great, but in some scenarios they'll give you noise. I lived with a daisy chained one spot for years without any problems at all, then I moved house and discovered hideous noise issues. Isolated supply fixed them. 

brucegill

Having just been in the same situation, a voodoo lab power supply sorted all my problems.

ecc83

OnTheHunt said:

ecc83 said:

Since the 'Mains Supply' is common to all states of the gear it follows that it is not the cause of the hum!

UK mains is very stable, very clean and not prone to 'spikes'. You do NOT need any filters or conditioners on it. IF you have crap on a mains supply it is the DEVICE PRODUCING IT that needs filtering (ever seen the BMthr filters in a MW oven supply?) .

You could have an earth loop, (aka, ground and hum loop) . You might be using more gain than direct into the amp. One common problem is that external 'line lump' PSUs themselves tend to radiate hum quite badly, keep them a mtr away from sensitive kit and leads.

It is a fact of electric guitar life that the things are noisy bstds, prone to picking up hum and other radiated crap. The more gain and gear you put in the signal path, the worse it gets.

Dave.

It isn't a gain issue, I get the buzz with just a reverb pedal in the chain, regardless of whether it's on or off.  Likewise with OD, exact same buzz regardless of whether pedal is engaged.

Earth/ground/hum loop - how does one address that?

It's tricky because a hum loop is formed when two pieces of kit have two 'earth' paths. In the simplest scenario, pedal A feeds signal hot and cold, earth, to pedal B and hence to G amp (which is earthed?) PSU feed 9V (say) DC  and the earth is common to both pedals. If each 9V output was completely isolated there should not be a problem but since guitar forums are awash with these problems, clearly it ain't necessarily so!

Said it before, Twere I, I would make up external packs using AA cells, per pedal.

Dave.

NPP

I recently had the same problem, after switching amps. Amp quiet on its own, with delay powered by its own dedicated PSU, and with pedals powered by batteries, but very noisy with some pedals powered by PSU. A new (old) PSU for the pedals cured it. It somehow makes sense - PSUs are always the cheap-and-nasty component in your rig ... 

OnTheHunt

Thanks for the help all.  So, I'm considering something like one of these:

https://www.andertons.co.uk/guitar-dept/electric-guitar-accessories/pedal-power-supplies/strymon-zuma-effect-pedal-power-supply

This will power my 9 and 12vdc pedals, all isolated.  For the one pedal I have which is centre +ve, I'll use something like this:

https://www.andertons.co.uk/guitar-dept/electric-guitar-accessories/pedal-power-supplies/t-rex-polarity-inverter-cable-orange

That all sound about right?

John_A

There are much cheaper options around that will do just as well. 

https://www.andertons.co.uk/bass-dept/bass-guitar-strings-accessories/pedal-power-supplies/truetone-1-spot-pro-cs7-power-brick

https://www.andertons.co.uk/guitar-dept/electric-guitar-accessories/pedal-power-supplies/decibel-eleven-hot-stone-smd-multi-pedal-power-supply

Gadget

OnTheHunt said:

Thanks for the help all.  So, I'm considering something like one of these:

https://www.andertons.co.uk/guitar-dept/electric-guitar-accessories/pedal-power-supplies/strymon-zuma-effect-pedal-power-supply

This will power my 9 and 12vdc pedals, all isolated.  For the one pedal I have which is centre +ve, I'll use something like this:

https://www.andertons.co.uk/guitar-dept/electric-guitar-accessories/pedal-power-supplies/t-rex-polarity-inverter-cable-orange

That all sound about right?

If you can afford the Zuma, do it. It's a great supply.

OnTheHunt

Gadget said:

OnTheHunt said:

Thanks for the help all.  So, I'm considering something like one of these:

https://www.andertons.co.uk/guitar-dept/electric-guitar-accessories/pedal-power-supplies/strymon-zuma-effect-pedal-power-supply

This will power my 9 and 12vdc pedals, all isolated.  For the one pedal I have which is centre +ve, I'll use something like this:

https://www.andertons.co.uk/guitar-dept/electric-guitar-accessories/pedal-power-supplies/t-rex-polarity-inverter-cable-orange

That all sound about right?

If you can afford the Zuma, do it. It's a great supply.

Reviews seem good indeed.  Between that and the Voodoo Lab Mondo - generally £50-60 more expensive than the Zuma, but this place has 'em at £232.  No 18V as standard but Voodoo do a voltage doubler cable which combines 2x9 or 2x12, not that I've any 18v pedals anyhoo so no great shakes.

https://www.musicstore.de/en_GB/GBP/Voodoo-Lab-Pedal-Power-Mondo-/art-GIT0026231-000?campaign=GShopping/UK&gclid=EAIaIQobChMIts7TrLLI2gIVDCjTCh20rwAnEAYYAyABEgLLsvD_BwE