Looping pedals off single supply

Barney · August 2023

I'm setting up a small FX board with 4 pedals on ...a EQ...Delay ...tuner and a drive ...I'm just wondering iff I can daisy chain the power supply and just a single 9 volt adapter .....

stickyfiddle · August 2023

Probably. Depending on the specific pedals you may run into issue with noise or not enough current meaning something doesn’t work. The delay is the only one likely to pose issues, in general, and then most of the time only if it’s something digital.

So.. which specific pedals?

Barney · August 2023

stickyfiddle said:

Probably. Depending on the specific pedals you may run into issue with noise or not enough current meaning something doesn’t work. The delay is the only one likely to pose issues, in general, and then most of the time only if it’s something digital.

So.. which specific pedals?

I have a boss EQ.. boss DD3 delay ....asmuse tuner and a Dumkudo drive

stickyfiddle · August 2023

I'm pretty sure the DD3 plays nicely on a daisychain. It might give you a tiny bit more noise than a full isolated supply.

I'd certainly start there and see how you find it before committing to spending more (assuming you already have a basic PSU)

Danny1969 · August 2023

The 9V adapter needs to be regulated ... otherwise it might be 9V into 100mA but then will fall in voltage with every extra pedal turned on.
It will also be higher in voltage if loaded less than it's rated load. So an unregulated adapter rated at 9V 150mA might be 12V when only 90mA is drawn for example.

All modern light adapters are switch mode design with a reference voltage which is referred to and matched by varying the pulse width (duration) of the switching cycles. These will keep the 9V steady regardless of load as long as you don't exceed the max current printed on it. Some of these are great but the cheapest ones are poorly filtered and decoupled so there's noise in the supply.

Older heavier adapters which are basically just a transformer in a box with 4 diodes are generally unregulated. This are still often supplied with some pedals .. I got one recently with a Soul Food.

I've never used a proper pedal board PSU, I've always just daisy chained off one decent SMPS.

english_bob · August 2023

^^^^ That.

The "industry standard" basic switchmode PSU is probably the Visual Sound One Spot. I used one for years and pretty much never had any problems with noise. Not very expensive, reliable and does what it's meant to do.

EricTheWeary · August 2023

I don’t imagine there’s a problem. If the delay creates a bit of noise might be easier/ cheaper to try a Joyo ZGP with it than look at alternative power supplies. Never heard anything but positives about how well those work.

ICBM · August 2023

*Properly designed* pedals do not need isolated power supplies. If they do, they aren’t.

OK, this isn’t going to help if it happens that your favourite pedal just happens to not be filtered and picks up noise from one of the others, but the idea that you need a fully isolated power supply that cost more than any of your pedals is overkill in most cases.

Barney · August 2023

Danny1969 said:

The 9V adapter needs to be regulated ... otherwise it might be 9V into 100mA but then will fall in voltage with every extra pedal turned on.
It will also be higher in voltage if loaded less than it's rated load. So an unregulated adapter rated at 9V 150mA might be 12V when only 90mA is drawn for example.

All modern light adapters are switch mode design with a reference voltage which is referred to and matched by varying the pulse width (duration) of the switching cycles. These will keep the 9V steady regardless of load as long as you don't exceed the max current printed on it. Some of these are great but the cheapest ones are poorly filtered and decoupled so there's noise in the supply.

Older heavier adapters which are basically just a transformer in a box with 4 diodes are generally unregulated. This are still often supplied with some pedals .. I got one recently with a Soul Food.

I've never used a proper pedal board PSU, I've always just daisy chained off one decent SMPS.

Thanks ..I just had a look it's 9 volt 850 ma ...do you think this will do ...I'm totally clueless on this type of thing

Barney · August 2023

ICBM said:

*Properly designed* pedals do not need isolated power supplies. If they do, they aren’t.

OK, this isn’t going to help if it happens that your favourite pedal just happens to not be filtered and picks up noise from one of the others, but the idea that you need a fully isolated power supply that cost more than any of your pedals is overkill in most cases.

I think probably the only one that it causing a bit of problem is the Asmuse tuner ...it seems when it's switched on by the by pass there is a high pitched oscillator type of sound ...not loud though .....the adaptor is 9 volt 850 ma

Danny1969 · August 2023

Barney said:

Danny1969 said:

The 9V adapter needs to be regulated ... otherwise it might be 9V into 100mA but then will fall in voltage with every extra pedal turned on.
It will also be higher in voltage if loaded less than it's rated load. So an unregulated adapter rated at 9V 150mA might be 12V when only 90mA is drawn for example.

All modern light adapters are switch mode design with a reference voltage which is referred to and matched by varying the pulse width (duration) of the switching cycles. These will keep the 9V steady regardless of load as long as you don't exceed the max current printed on it. Some of these are great but the cheapest ones are poorly filtered and decoupled so there's noise in the supply.

Older heavier adapters which are basically just a transformer in a box with 4 diodes are generally unregulated. This are still often supplied with some pedals .. I got one recently with a Soul Food.

I've never used a proper pedal board PSU, I've always just daisy chained off one decent SMPS.

Thanks ..I just had a look it's 9 volt 850 ma ...do you think this will do ...I'm totally clueless on this type of thing

With that small an output current I'm guessing it's ol skool transformer type .. heavy compared to phone charger ? If it is then the unloaded voltage when running just a drive or something on it's own will be higher, and although the transistors and opamps of drive pedals will happily take a much higher voltage you can't take for granted the coupling / decoupling caps are rated much higher, 10V and 16V being common values so if it's the older heavy unregulated type don't risk it.

A lot of tuners make a noise when engaged, my Polytune does but the Boss doesn't. As ICBM said some pedals just aren't that well designed in terms of noise in the supply.

Barney · August 2023

@Danny1969 it's a new power supply from Amazon ...do you think will maybe be getting a truetone 1 spot power supply or will this do ?

BillDL · August 2023

I use a TrueTone 1 Spot power supply with a 5-way daisy chain and it is a lot quieter than other generic "wall wart" switching power supplies.

Sassafras · August 2023

The 1 Spot's only about 25 quid and it works fine. Very quiet and reliable. It pumps out about 1700 ma.

Danny1969 · August 2023

Barney said:

@Danny1969 it's a new power supply from Amazon ...do you think will maybe be getting a truetone 1 spot power supply or will this do ?

I wouldn't use the one you have as it's not regulated

ICBM · August 2023

Sassafras said:

The 1 Spot's only about 25 quid and it works fine. Very quiet and reliable. It pumps out about 1700 ma.

This is actually what I don't like about them - that's too much. The problem isn't obvious until something goes wrong - if you accidentally connect it to the wrong polarity pedal, or something like an internal voltage regulator decides to die, the current capacity is so huge it will keep on feeding power into the protection diode or regulator without missing a beat, until the component burns up completely and then feeds the wrong polarity/excess voltage into other more expensive parts... ending up with an expensive pedal that's now beyond economic repair, whereas with a lower-capacity supply the supply shuts down and you just change the diode or the regulator and it's fixed.

OK, this is a *fairly* rare problem and if you're not using any reverse-polarity pedals it's even less likely, but I've seen it enough times to be quite wary of recommending them.

Danny1969 · August 2023

I have fixed quite a few pedals where the reverse polarity protection diode has been cooked into open circuit and then the rest of the circuit destroyed. If the diode was in series it wouldn't be an issue or if they used a biased FET as protection it wouldn't be an issue but in guitar land things that are done wrong originally have to be kept wrong for some reason.

What tends to happen is customer gets a pedal, doesn't have a battery so connects the adapter they used to run the radio or whatever and it simply doesn't occur to them pedals are neg centre and to be fair why would it ... nothing else is !

Barney · August 2023

Thanks everybody ...IV went and ordered the one spot transformer...hoping everything will be ok .... @Danny1969 I just blew a tube screamer pedal recently exactly the way you said

andy_k · August 2023

I'm running a couple of small boards from a 9v rechargeable, and usually only one or 2 of the pedals are on at any one time, just for home use.
Biggest I have is 5 pedals, Klone> Angry Andy>Blue Fool> Wrecktifier> Ghost Echo ( big Fuzzdog fan), usually the Ghost echo is on all the time, and often the AA and the Klone are on, I think I timed it once with all on, lasted 30 mins, obviously mains would be better, or an expensive rechargable PB, but I have no probs doodling at home for a while then simply making sure I charge up the 9v when I'm done.
Another board, if you can call it a board, is just a Klone into Angry Andy, and that goes for longer than I ever care to play.
I tune up before I start anyway.

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Looping pedals off single supply

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