Do I need an isolated power supply?

We've written a lot about isolated power supplies, what they are, and how to use them. But in this article, I'll answer the question of whether or not you need an isolated power supply.

Is it important if you have just a few pedals?

What if you have a lot of guitar pedals?

Compared to non-isolated power, is it important enough to have isolated power for the added cost?

We'll answer this question for multiple scenarios.

Need to buy one? Best guitar pedal power supplies

When would I use it?

When would you need an isolated power supply? There are some specific scenarios we can outline where it would be recommended.

If you Have Two or More Pedals

If you already have more than one guitar pedal, we would recommend using an isolated power supply. This is because shared power or "daisy chains" can cause noise and electrical interference in your guitar's signal. It essentially "dirties" the sound and can get worse over time in devices that share power.

You could also use individual power adapters or 9V batteries, but batteries run out quickly and simple 9V adapters can be cheap and can have noise issues as well, especially when you're using multiple adapters in one signal chain.

For planned expansion

The next scenario is if you only have one or two pedals but plan to expand your pedalboard in the future. As you add pedals, the need for an isolated power source increases.

We'd recommend adding an isolated power supply in anticipation of the new pedals you'll add in the future.

For reliability

Our third and - perhaps - simplest reason is for making your electric guitar rig more reliable. Isolated power supplies cut down on noise, run smoother, and are more reliable than any other power sources.

For Gigging

In the spirit of reliability, those who are gigging or playing live in any capacity should consider an isolated power supply. When you're playing live, you don't want to worry about noise issues or batteries running out, so it's extremely helpful to have an isolated power source on hand.

When would I not need it?

There aren't too many situations where we would not recommend an isolated power source, outside of the following scenario.

If you Only Have One Pedal

For guitar rigs that only have one guitar pedal and don't really plan on expanding, a single power adapter is a sufficient power source. You do not need a fully isolated power supply in this situation.

This is because one adapter - in and of itself - is a form of isolated power.

If you only need to plug one in and the power isn't shared between multiple pedals, there's no opportunity for electrical interference. Some people setup their rig with a single pedal, like a tuner or EQ, which means you don't really need a multi-pedal power source.

Using one 9V battery for a pedal is still considered isolated power.

What about multiple pedals with a separate adapter for each?

The problem with multiple adapters is that they're usually plugged into the same power source, perhaps a shared wall socket or a surge protector. While this is convenient, it's still not strictly isolated as the two or three adapters are coming from the same spot.

If You're Comfortable with Multiple 9V Batteries

On that note, if you don't mind the cost and limitations of 9V batteries, they do get you a form of isolated power. It's just not the most efficient way to do so. If that doesn't bother you, maybe you could put off the isolated power supply purchase.

The Problem with Multiple 9V Batteries

Some of the downsides with 9V batteries include cost, and the length of time it takes to run them out. With guitar pedals, they generally don't last very long (most guitar pedals are power hogs).

Is it the same as an "isolated PSU"?

Yes. You might see isolated power supplies described as an "isolated PSU" which is the same type of device.

How do I know a power supply is isolated?

While there are some pretty in-depth technical issues related to true isolated power, there are two non-technical ways that I recommend identifying it for guitar pedal concerns:

1. Naming conventions of the power supply/specs sheet
2. Price of the power supply

Most power supply manufacturers will state clearly whether or not their supplies are isolated. If they don't, it's safe to assume the power source is not isolated. You can see plenty of isolated language in the screengrab below for the Voodoo Lab ISO-5:

However, not all power supplies that claim to be isolated necessarily are.

The "fail-safe" I recommend using is simply the price.

Power supplies under $100 that claim to be isolated should be very suspect, and subject to electrical scrutiny. I rarely see a truly isolated power source come in under the $100 price point.

Most run between $150 and $250, powering anywhere from five to 12 guitar pedals.

Isolated VS non-isolated

For review, isolated power supplies insulate each power source from one another, despite sharing the same circuit. Non-isolated power supplies share the same circuit and the same electricity, increasing the propensity for noise and electrical interference in your signal.

Identifying: Isolated power supplies

Conclusion

In most cases, we would argue that an isolated power source is needed, especially if you're running multiple pedals. You can get away without it in limited context, but serious electric guitar players should consider adding isolated power to their rig. If nothing else, it'll help keep your noise levels low and give you room to expand your pedalboard if you choose to in the future.

Your Questions

Do you have questions about isolated guitar pedal power or something else we mentioned in this article?

If so, drop us a line in the comments section below and we'll jump in to help out.

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