This is one of the most common questions from guitar players the minute they reach the studio.
It is also a very common doubt for home-studio owners because many audio interfaces offer two or more inputs and a general phantom power. This generates the doubt because, for example, acoustic guitars do have a preamp that requires power, but they are (usually) powered by a 9-volt battery.
Will it harm the guitar to add the two power sources together?
And, can phantom power actually do damage to your guitar?
No, phantom power can’t do damage to your guitar. But you have to assure yourself you’re doing everything right. Here’s what you should know.
The first thing that you need to question is whether you are plugging the guitar in through a XLR cable or not. If you are going from your guitar into the audio interface with a ¼ TS guitar cable, then your guitar is just not picking up that extra voltage from the source.
For example, in my home studio, I have to make my demos an M-Audio Fast Track Pro and it has one XLR input and one ¼ input.
Many times I just set it up to sing and play and record both sources at the same time. To do this I have to turn on the phantom power for the condenser and plug in the pre-amp of my guitar with a common guitar cable.
My guitar just ignores the power from the interface and doesn’t hurt it at all.
Of course, what you need to always do is to check the owner’s manual and see what it says about the phantom power in the unit.
What Is Phantom Power?
Phantom power is an electrical current that can go through a cable to feed a microphone or any other connected apparatus.
There are some microphones, especially those that fall under the category of condenser that need electrical power to work. Those may not provide any other socket than the XLR input to receive it.
The phantom power that we know today is not a new invention. It has been powering microphones and telephones since 1919. The year 1964 was the release of the first commercial microphone to use this technology.
Since then, it has been virtually unchanged. You can benefit today from the same benefits of warmth that condenser microphones have been giving to music for decades.
If you look at a typical XLR cable, you will notice that it has three legs to plug it in. Two of those are positive and one is ground. This causes the XLR to have absolutely no noise regardless of the extension.
Phantom power is usually engaged from a little button present in all kinds of consoles, mixers, audio interfaces and Dis.
Nowadays, it is even possible to buy external phantom power sources to power a condenser microphone when there is no possibility in the console. Because of the phantom power, condenser microphones are capable of generating most of the warmth we hear on vocals and instruments.
Does My Acoustic Guitar Need Phantom Power?
For the guitar to be plugged into either an amp or a console (or an audio interface), it requires some kind of a pickup which is mostly combined with a prea-mp powered by a 9 volt battery.
Since the pre-amp itself has a power unit, the answer is NO, for most guitars.
This being said, most acoustic guitars are not recorded with a cable to a console but with condenser microphones such as the Shure SM81. This kind of microphone requires a phantom power unit to work, so indirectly in recordings you do hear it.
There are certain Gibson models featuring a passive pickup like the L.R. Baggs LB-6. It don’t have a pre-amp or a 9-volt battery, but does not require any kind of phantom power either. They can be thought as a regular electric guitar needing to be amplified.
To answer the above question, what we need to say is NO – your guitar does not need phantom power to work.
Is It Bad To Leave Phantom Power On?
Although today, we all make an effort to try and make the world a greener place. This means to rationalize the way we use the electrical power available in the planet. Hence, from environmental point of view, you should not leave on phantom power or any studio equipment that you won’t be using (or the toilet lights in any case).
If we want a better world, we have to start with the little things.
Will phantom power affect any instruments if we plug them in and it is on?
Well, bearing in mind that the voltage that phantom power is capable of generating mostly travels through an XLR cable only, it is kind of safe for guitars. That’s because it is very uncommon to plug them in with such a cable.
There is a very common, expensive and great sounding type of microphone known as red ribbon (RCA 77DX for example). In this case, it would be massively hurt if we plug it in and the phantom power happens to be on.
Most other microphones that do not require phantom power simply reject the voltage.
Finally, no console or audio equipment gets damaged because the phantom power is on for many hours. They are designed to endure long studio hours.
However, if you want to cut some expenses for your next electricity bill, I recommend you turn everything off when you are not working.
Does Phantom Power Affect Sound?
Well, there are two ways of answering this question that have opposite results. Let’s go through both of them.
It affects the sound positively on condenser microphones
The warmth of the sound that comes from recordings made with condenser microphones is a proof on how phantom power affects the sound positively.
There are legendary microphones like the Shure SM81, which is the one that you would use to record an acoustic guitar. It is rich in mids and lows whereas the SM57, the indicated one to record electric guitar, is more moderate in lows and more focused on the mids and the mid-high frequencies of your instrument.
In fact, it is so good in mids that you can capture a snare drum or even vocals.
This difference is not casual. The SM57 is a dynamic microphone and the SM81 is a condenser, needing phantom power. That drastically changes the sound.
Some users report hissing on recordings
While it is not 100% of the users, it is been noted by many of them that in some audio interfaces engaging the phantom power adds a hissing sound to the recordings as a back noise. A “phantom or ghost” noise.
The best way to check it is to just plug your favorite dynamic mic, turn off the phantom and look for the noise. If it is still there, replace it something else, like the XLR cable.
Otherwise, if you have a faulty phantom power unit, you might have to get it replaced.
Does Phantom Power Only Work With an XLR Cable?
The answer to this question is yes.
If you see some kind of equipment labeled with “Phantom Power”, you will very likely see an XLR connection available.
This will give voltage to the microphone through the cable. You can have bias power on your guitar or use a TRS ¼ plug cable.
Still, it is very rare to encounter such scenario. Phantom power is mostly found on XLR connections.
Do Guitar Amps Have Phantom Power?
There are several models that do have it. Some others don’t. Let’s go through the top 3 options:
AER Compact 60
IMO, there is no better option in terms of an acoustic guitar amplifier than buying an AER.
This brand has been manufacturing state of the art acoustic guitar amplifiers for elite players around the world for some time now. Most people say it is the best-sounding one in the market today.
It features twin channels and is perfectly tuned to work with the piezoceramic pickups.
The result is a crystal-clear and powerful sound. It has built-in phantom power, so it is suitable for condenser microphones.
Check it out on Amazon, here.
Next in line, counting the acoustic guitar amplifiers that sound the best, is Roland AC-60.
This good-looking amp is stereo with two 6.5” speakers giving some more life to the DSP built-in effects.
It has a technology to avoid feedback and maximize its volume without suffering any squeals or low rumble. This portable unit also has phantom power to accommodate condenser microphones.
Check it out in more details on Amazon, here.
Fishman PRO LBT-500
Last, but definitely not least, is this amp from the worldwide known acoustic preamp brand Fishman.
This amp is also 60 watts, like the last two. It also features onboard effects, 2 channels and phantom power as the rest on the list.
What the Fishman offers that both other ones don’t is Bluetooth connectivity.
This might seem as a minor detail, but the capability of playing the backing tracks from your cellphone without any cables to play along is great.
This feature is particularly handy for any performer or practicing musician. This good-looking gold and brown amp is very light and naturally tilted to be used as a monitor.
Check it out on Amazon in more details, here.
I hope this article gave you some valuable insights and information about this topic. If you enjoyed reading it, I’m happy about it.
Don’t forget to check out other interesting articles about various guitar topics and issues!
Cheers, and rock on!