Isolated vs Daisychain Power Supplies Part II

In a previous video I covered how noise can be passed between effects pedals when using a daisy chain power supply. Several people complained it was not a fair test because I used a battery for the isolated supply. But does it really make a difference to this issue?
In this video I redo some of the tests, and we measure and listen to the results to see if there is any difference. As before, after the tests we explain the reasons behind why we got these results.
Part 1 - Isolated vs Daisy-chain Power Supplies - • Isolated vs daisy chai...
Current wars II - AC vs DC pedal-board power supplies - • Current Wars II. AC vs...

[@kimgaugemusic]

had this issue recently. I'm currently daisy chaining a Tc Triple delay, Splash Stereo+ MK3 reverb and a Zoom ms-70cdr pedal with no audible problems, but as soon as I introduce either the Meris Mercury 7 or the MXR 300m reverb, I get that high frequency switching problem. Until I saw this video, I didn't know that it was high frequency switching that was the problem. I always thought it had something to do with a ground loop being setup somewhere in the chain. Thanks for the helpful information!!

[@housemachine509]

Awesome follow up. One spot solved all my issues. Trex was a noise bucket.

[@rossbrigolimusic]

A valid test for daisy chain would be to use the same blue power supply, and use a daisy chain cable power all pedals from one output. I think you will be surprised.

[@stanislavvartanyan9430]

Dear James, Thank you for your excellent videos on power supplies - very instructive. I have a few questions regadgin 529. First, the unit markings... There are two explicitly indicated groups of power outputs if you look at the unit itself. One is four 150mA outputs, that are kinda graphically grouped together, and explicitely marked as ISOLATED. Which is fine. But then there's the 5th 500mA output socket... which is not market ISOLATED. Why? I assume it is also isolated, given that the other 4 out of 5 are lol, but could you pls shed some light on this. The second question is somewhat silly maybe, but still: can I daisy-chain 2-3 pedals on low current outputs, provided that I am still within the 150mA limits? For instance, I have an all-analog boost pedal (Xotic), and a couple of signal routing switches that only use power for LED indication, and an active expression pedal. Their total combined current draw would max out at around 70mA, so would I be fine? And third, is it safe to use current doubling cables with 529? The reason I am asking is that I have two pedals on my board, which require 300+ mA. Can I feed one from a dedicated 500mA socket, and then use a current doubler cable (yes, I think I know the difference between current doubler vs voltage doubler cables)?

[@JamesLebihan]

The 500mA output is a separate circuit. Since it is only a single output, it is isolated by nature. You can daisy chain multiple devices to a single output as long as you do not exceed the current limit for that output. Note that these devices will no longer be isolated from each other (although they will be isolated from devices on the other outputs). By 'current doubling' do you mean you want to connect two outputs on the 529 in parallel to a single device to increase the current available to that device? If so, then yes, this should work.

[@stanislavvartanyan9430]

James Lebihan, thank you for your prompt reply. That’s all I needed to know. Sure, I realiz that daisy-chained devices on a single output will not be isolated from each other, but since I am planning to carefully group them so that digital pedals are on their own outputs - should be fine. And yes, I was referring to connecting two outputs for combined current supply. Glad to know it will work.

[@exceptions9263]

James - I'm shopping for a new rig, and I was thinking of using a supply like a 1-Spot with a Gig Rig Isolator. The Gig Rig seems awfully small compared with the usual isolated supply. Is it possible that it's just as good or is there something else at work?

[@JamesLebihan]

I don't have personal experience of the Gig Rig Isolator so you may want to check with the manufacturer, but from the published specs, I don't see why this wouldn't work. Each output is rated at 135mA which is not enough for large digital pedals such as some Strymon or Eventide devices, but if you are just using low power pedals it should be OK.

[@Yupppi]

Now seeing that 60 cycle hum repeatedly coming from the amp in these videos, is it not feasible to filter that hum out? Since it is a very old phenomenon, but it seems like it persists to this very day. Also is it different in Europe for the 50 Hz? If you could filter it effectively, you would have to have different amp versions or a switch or built-in "smart" system to accommodate it and touring around the globe with your own rig would be more work, wouldn't it? Or maybe I'm getting the whole picture fundamentally wrong for not really understanding a lot of it. And then there's the clock in analog delays that is either filtered with loss in high frequencies or left in with clicks. Can that cause funny side effects with digital pedals or compromised power conditions?

[@JamesLebihan]

This AC noise is dependent on the frequency of the AC supply. It will be 50Hz in locations where that is the frequency of the supply. It's not really a matter of filtering in 'out' it's more filtering it 'down', which it already has been in the devices used in this demo. Filtering is done in stages and each stage gets harder and more expensive. Products will only go as far as appropriate for the use case and price point.

[@Yupppi]

@@JamesLebihan thanks for the response. I assumed it had to be something like diminishing returns. Looking forward to the pedal power supply series future episodes, really liked the content so far. Hopefully this channel gets some visibility, you see people asking the exact questions answered on these videos day in, day out.

[@androidgameplays4every13]

If I use all analog pedals then using a daisy chain would be ok?

[@JamesLebihan]

In most cases a diasy chain power supply is fine for analog pedals as long as the power consumption of all the pedals added together is less than the maximum output of the supply. Some pedals that have an analog audio path might still have digital components in them that can sometimes cause noise so you can only be sure by trying it.

[@egogreen2045]

1:48 you didn't activate the pedals not as in non battery 2:30. Why

[@JamesLebihan]

The noise we are measuring here is switching noise passed over the power cable. This is present as soon as the devices are powered up. It's present whether the effects themselves are bypassed or not.

[@apkhazavagiorgi]

is it any chance to make isolated power supply from a non-isolated ? (rebuild it)

[@JamesLebihan]

We have something in the works

[@apkhazavagiorgi]

@@JamesLebihan any schematic ??? Isolated are expensive ... All i have non isolated junk... :(

[@JamesLebihan]

We are working on a device that will connect to a daisy chain output and isolate it. It should be fairly low cost. I cant share the schematics I'm afraid. Sorry.