Isolated output on power bank

[tuckster]

Hi everyone,
I'm searching for a way to isolate an output of my Sanyo Eneloop 9V Powerbank.
My pedalboard has four pedals one is an EHX Looper which adds a lot of noise.
I noticed that there is something nice and shiny for a lot of money named "Cioks 4" which converts a lot of different input voltages from 5V to 12V (AC or DC) to 9V/18V DC.
But it's ways too expensive.
Would this little fella be enough for my needs? Mean Well SKMW06F-09 https://www.meanwell-web.com/content/files/pdfs/productPdfs/MW/SKMW06/SKMW06,DKMW06.pdf
Input 9-36V DC Single Output 9V DC 667mA. The shutdown Voltage is 5,6V so 9V as minimum should be fine.
My powerbank delivers 2A total.
It's a bit pricey but the cheapest option compared to Murata or Traco converters with this high output current.
Any other sugestions?
Thanks

[Rob Strand]

Have you tried powering the EHX Looper with its own supply.   There's a chance the noise won't change because the looper itself is noisy not the supply.   What I'm saying is how sure are you that isolation will solve the problem?  And if it does fix it why not just use two adaptors.  Two adaptors is cheaper than a supply isolator.

When you start putting in DC/DC converters you have to be prepared for the fact you might create new noise problems.
Also DC/DC converters are not 100% efficient so it could flatten you batteries much sooner.    There is generally an idle current on the converters which means power is being used with no effects connected.   There's a chance you could flatten the batteries by leaving it plugged into the converter.

Apart from my first comment you can do things like put 4.7 ohm to 10 ohm resistors between the common DC input -ve rail point and *each* DC output -ve rail which goes to each pedal.     For the looper you can add an electrolytic cap on the effects power rail.   There's other solutions as well like adding inductors.   For low power pedal you can use 10 to 47 ohm resistors but because the looper pulls a lot of current try the smaller values.

[tuckster]

Hi Rob,

I tested a bit with different combinations and it's always my Fuzz that causes the noise. Only when both pedals are connected at the same time.
Fuzz with different pedals -> silence
Looper with different pedals -> silence

So is it really the Fuzz? Is it the looper? How do I find out?

[anotherjim]

Make an adapter with this simple power filter. Put it in the feed to a suspect pedal. I made a multi-output adapter with this on all outputs and have never had an issue with pedals creating noise problems with the others on the supply.

[idy]

What kind of fuzz? Charge pump and PNP positive ground?

[tuckster]

Make an adapter with this simple power filter. Put it in the feed to a suspect pedal. I made a multi-output adapter with this on all outputs and have never had an issue with pedals creating noise problems with the others on the supply.

I remember having something in a box somwhere in the basement: Palmer Purifier

It never helped solve my noise issues but maybe this time

What kind of fuzz? Charge pump and PNP positive ground?

Aion FX Aperture (AMpeg Scrambler - the old one) https://aionfx.com/app/files/docs/aperture_documentation.pdf

[Rob Strand]

So is it really the Fuzz? Is it the looper? How do I find out?

You need to do to power the looper separately to see if it fixes the problem.  If not then it is unlikely an isolator will fix the problem.
- current power: pedals -> looper    --->  noisy
- looper powered separate in same configuration  ---> noisy or not?

I suggest using two of Jim's circuit with 4.7 ohms instead of 47 ohm.   One circuit powers the looper, the other supplies the rest of the pedal.    The idea is *not* to clean the supply.  The idea is to isolate the supply to the looper from the other pedals.

Digital pedals can put noise on the supply and grounds.  The single -ve supply terminal connects to each effect.  The pedals connect the -ve supply to ground.  The audio grounds connect via the external jack.   That means power can flow into the DC jack of one pedal through the audio ground then supply power to another pedal.  In effect putting power supply noise onto the audio.   You can't make audio flow down the audio cables and power down the power cables.  They are just wires and the electrons find what ever way to go.    Those isolation resistors try to prevent the power noise getting onto the audio ground.   It also stops noise on the +9V feeding back into other pedals.

[anotherjim]

Yes, it's the resistor in the power return as well as the +feed that makes the difference. 4R7 as Rob suggests will probably be better since I suspect the looper is quite power hungry and may not like too much voltage drop.