Three of my pedals just died!

[Pea Turgh]

Luckily not my gig board, nor my brand new Zoom MS70, but I have a cheap “messing around” board with 4 pedals (tc analog Tailspin vibrato, Echobrain delay, Drip digital spring reverb) and an Ammoon looper, all powered by a Nordell Audio power supply.

All seemed fine - had a loop just playing while I was searching for a patch cable.  Then the  looper just stopped playing.  Power supply still lit up.  The only pedal that seems ok is the digital reverb, the other three will no longer function!

Any ideas on how the hell that happened?  Please?!

[Chiliwailer]

Were you using a daisy chain with an exposed output that wasn’t being used? I heard years back from a pro tech that can cause issues if it touches a metal pedal casing. 

Edited January 17, 2021 by Chiliwailer

[Pea Turgh]

No daisies were involved.  Each pedal had one lead going to the power supply.

Just wondering if there was a spare plugged in but not connected to a pedal, actually.  Oh, man - such a small thing but it’s really rained on my parade!

Edited January 17, 2021 by Pea Turgh

[Chiliwailer]

Very annoying 😡

Perhaps some kind of short unfortunately. 

[rmorris]

On 17/01/2021 at 15:58, Chiliwailer said:

Were you using a daisy chain with an exposed output that wasn’t being used? I heard years back from a pro tech that can cause issues if it touches a metal pedal casing. 

Yes - with a typical (for guitar stuff) centre negative dc jack the outer barrel is V+ and a metal case is OV. So touching can short out the PSU - although often the paint on the pedal will avoid that happening,

That may damage the PSU if it isn't protected against - but not the pedal since no significant current reaches it.

[rmorris]

On 17/01/2021 at 16:07, Pea Turgh said:

No daisies were involved.  Each pedal had one lead going to the power supply.

Just wondering if there was a spare plugged in but not connected to a pedal, actually.  Oh, man - such a small thing but it’s really rained on my parade!

I looked up the supply on Google/Amazon. Seems its outputs are individually protected.

It's possible that the problem is with failed PSU outputs rather than the pedals ?

Have you tried the pedals on other knowingly good supplies ?

 

[Pea Turgh]

The power supply’s wall wart is effectively a single psu (centre negative, 9v dc) - first thing I did was pull it all apart to start problem solving. One of the four pedals (digital reverb) still works, but the two analog pedals and the (digital) looper only show power, but pass no signal.

I was going to try batteries, as I had a wah many moons ago that would only work with a 9v.

[Andyjr1515]

Try taking one out of the loop at a time.  Might be that the bypass signal isn't getting through either because of a pedal or faulty patch lead/jack.

[Pea Turgh]

23 minutes ago, Andyjr1515 said:

Try taking one out of the loop at a time.  Might be that the bypass signal isn't getting through either because of a pedal or faulty patch lead/jack.

I pulled the lot off the board so I could test individually, using two leads I know work, and a power supply I know works.  No joy!

[LeftyJ]

19 hours ago, Pea Turgh said:

The power supply’s wall wart is effectively a single psu (centre negative, 9v dc)

If it runs on an external power supply, it's very unlikely its outputs are fully isolated. All the 9V outputs probably run a common ground. Ideally you'll want a multi-tap transformer on the power supply itself, when going from 230V to 9V. The Nordell is a rebranded Joyo JP-02, which is sold under many names. It has an external switching power supply, and most definitely does not have isolated outputs. True electrical isolation requires a transformer with separate secondary windings for each output section and this is why the products from Voodoo Labs, T-Rex, and others are more expensive (and also why they are a bit bigger and heavier.) The T-Rex Fuel Tank Chameleon has a transformer with 5 independent secondary windings and 5 voltage regulators. The Joyo product in contrast has only 2 voltage regulators: One for all of the 9v outs and one for the 12v out. (The 18v out comes straight off the wall-wart voltage.)

That would explain why more than one output failed at the same time. It only has some sort of short circuit protection.  

This site offers an excellent and rather in-depth comparison of most power supplies on the market today: https://stinkfoot.se/power-supplies 

I don't know enough about electronics to understand how it could have damaged your pedals. Your TC pedals require a minimum of 100mA, and the looper draws 94mA. The 9V outputs of the Nordell are 100mA each, so that should be just enough. The external power supply gives 18V at 1000mA. 

Edited January 20, 2021 by LeftyJ

[Pea Turgh]

I’m just glad my gig board wasn’t involved!

[Andyjr1515]

6 hours ago, Pea Turgh said:

I pulled the lot off the board so I could test individually, using two leads I know work, and a power supply I know works.  No joy!

So all three of those pedals don't work at all?  OK...that's weird

[Pea Turgh]

Three dead, one survivor.  Yes - weird!

[LeftyJ]

22 hours ago, LeftyJ said:

Your TC pedals require a minimum of 100mA, and the looper draws 94mA. The 9V outputs of the Nordell are 100mA each 

Come to think of it, I think this might very well be your problem. If the output transformer of the Nordell is straining to provide more current than it is capable of (the 100mA limit per output) the output voltage may drop and this may cause your pedals to either not work, or for things to get damaged by underpowering them. Your power supply needs to provide a higher current than your pedals require, so they can draw as much from the output as they'll need. TC Electronics only specifies the minimum current rating, but not the maximum so it's hard to tell how many mA they'll draw at their peak.

The switching power supply can also be an issue, as these often don't like mixed loads. 

Edited January 21, 2021 by LeftyJ

[Pea Turgh]

It’s worked for so long though!  I’ve had it for a few years, and had many different pedals - 8 at a time sometimes.

Sticking with my Zoom MS70cdr (on batteries) for now!

[rmorris]

On 21/01/2021 at 09:23, LeftyJ said:

Come to think of it, I think this might very well be your problem. If the output transformer of the Nordell is straining to provide more current than it is capable of (the 100mA limit per output) the output voltage may drop and this may cause your pedals to either not work, or for things to get damaged by underpowering them. Your power supply needs to provide a higher current than your pedals require, so they can draw as much from the output as they'll need. TC Electronics only specifies the minimum current rating, but not the maximum so it's hard to tell how many mA they'll draw at their peak.

The switching power supply can also be an issue, as these often don't like mixed loads. 

Errr...No. realistically, semiconductors handling small signals don't get permanently damaged by being underpowered.  It's just not a 'thing'.

 

Edited January 25, 2021 by rmorris
Clarification of technical detail.

[John Cribbin]

The only thing I can suggest is some form of voltage spike which has blown the circuits.

For at least the last 20 years, all my electronic stuff has hooked up to the mains behind 'surge protector' plugs. Cheap way to add a bit of electrical safety.

This kind of thing, available everywhere:.

https://www.screwfix.com/p/masterplug-13a-4-gang-unswitched-surge-protected-extension-lead-2m/8068g