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Preamp Question/Real Simple

Ive been recording for awhile but I use an Emu 1820M with phantom power to power my Studio Projects B3 Mic.

Now I am going to feel like a total idiot for asking this, but here goes.

Lest say I have a sweet pre-amp, like an Avalon 737.
What good will that do if my mic is supposed to be phatom powered?

I guess cause I dont have the knowlege of preamps is why I ask. Ive never really had to worry about it because my Emu has phantom power.

I mean why would preamps matter for a condensor mic if it is sopposed to be phantom powered? Or am I wrong? Like do some phantom power sources sound better than others?

Or is it just the fact that the signal runs through the Avalon or other preamp, which may have tube or valve technology, which gives a certain charachteristic to the vocals? Which is why a good Preamp would matter.

Could someone explain.
Im talking about recording vocals only.



RemyRAD Wed, 03/07/2007 - 21:39
Dozer, they call it "Phantom" power, because it is electrically there while not being "electronically" or sonically there. While a bad phantom power supply can and does add terrible noise to a microphone signal. So, it must be carefully regulated, highly filtered and carefully electrically balanced between pins 2 & 3 with reference to ground on pin #1, and is supplied to pins 2 & 3 through .5% (mil spec) tolerance, 6,800 ohm resistors. Because the same voltage appears at both pins 2 & 3, which is a differential balanced input, the 48 volts actually electrically cancels out. It's simple math, which I'm really bad at but think of it this way: +48 volts into positive pin 2, plus +48 volts into negative pin 3 = 0 volts across pins 2 & 3, since it all canceled out in a differential circuit.

Non-polarized diaphragm condenser microphones generally require a full 48 volts. While "Back Electret" permanently polarized diaphragm condenser microphones can utilize a phantom power voltage of as little as 1.5 volts and so, some can be powered with a single AA battery, since the diaphragm is already polarized and you only have the power a single transistor in the circuit within the microphone. Otherwise, all phantom power should have no effect on sound whatsoever.

WARNING! WARNING! Will Robinson, ribbon microphones can easily be destroyed by phantom power! Dynamic microphones are less susceptible to damage from phantom power. On my API mixers and Neve consoles, I cannot individually switch the phantom power off for the microphones that don't require it so, I am always running a risk, every time I plug-in a ribbon or dynamic microphone. So far, no deaths in the family.

I'm really not hear. I have Phantpun power.
Ms. Remy Ann David

Hemophagus Tue, 03/06/2007 - 09:54
It's all about power...

Hi Dozen,

I think you're a little confused about what "phantom" power is...

Phantom Power (which is usually 48v, but not always) is a need for the microphones that use voltage for making it's acoustic-electronic transducer work, suchs as Condenser and many piezo and electret microphones.

Dynamic microphones do not need phantom power because they are based in a magnetic induction process, so the capsule movement is transduced to an electronic signal. In condenser microphones, for example, there's a need of voltage to apply on the capsule in order to get it work, so the sound pressure makes a thin metallic membrane move and transduces this to an electric signal.

Check out for the web to know more about microphone types.

Referring to the preamp's question, of course an Avalon 737 will be better than the Emu! It's like a comparison between a CAD microphone and a Neumann U87, they both are mics, but they don't sound similar in fact!! The Avalon is a nice preamp, with prime quality components inside and a nice PCB design... the sound you get from it will be definitively better than the sound you get from the Emu...

Cucco Wed, 03/07/2007 - 06:12
Dozer wrote:
I understand what your saying about the operation of phantom power.

It doesn't sound like you do.

Phantom power, for the sake of argument, has no effect on the quality of the sound.

(Before some of the techies jump in here and beat me over the head and further confuse the issue, let me state that I mean if all things are equal and the phantom power supply is generating a full and clean 48V)

In fact, phantom power is referred to as "phantom" for two reasons.

1 - if "on" it has no effect on mics that don't require it. They don't "see" the voltage.

2 - it has no impact on the sound.

Of course, for a condenser to work, it must have 48V (again, for the sake of argument here...)

Most preamps will supply 48V phantom power.

Where the sound quality comes in to play is NOT at the powering stage, but at the amplification stage, and any other stages (depending upon the type of pre being utilized.)

Some amplifiers (mic preamps) use tubes to amplify their signals. Some use transformers. Some use Integrated Circuits (ICs)/Operational Amplifiers/Field Effects Transistors (FETs).

This is the area of the mic pre which has the most impact on sound.

Other aspects which affect sound quality are:
Power supply (not the 48V phantom, but the actual 110/220V supply)
Quality of internal components or lack thereof
Amount of components and type of components used

FWIW, I don't like Avalon gear in general especially not the 737.

Cheers -


Dozer Wed, 03/07/2007 - 13:31
I understand that phantom power is just used to power the mic, like Hemophagus said.

I wrote in my first post.
Or is it just the fact that the signal runs through the Avalon or other preamp, which may have tube or valve technology, which gives a certain charachteristic to the vocals? Which is why a good Preamp would matter.

Which is more like the answer.

I only used the Avalon 737 as an example because I always hear people saying good things about it. Ive never used one.

Thanks everyone for your help.