Topic: Pre-amp? Battery box? What's the difference?

[evilchris]

I tried searching for an answer, but I couldn't find one that made sense to me from a source that I could trust.

What are the fundamental differences between a pre-amp and a batt. box?  I'm currently using a batt. box to run my mics line-in, but the batt. box has a gain control knob and bass roll-off options, so I have a little bit of control over what, exactly, is fed into the MD recorder.

What are the advantages or disadvantages of one type of gear over the other?

[Church-Audio]

I tried searching for an answer, but I couldn't find one that made sense to me from a source that I could trust.

What are the fundamental differences between a pre-amp and a batt. box?  I'm currently using a batt. box to run my mics line-in, but the batt. box has a gain control knob and bass roll-off options, so I have a little bit of control over what, exactly, is fed into the MD recorder.

What are the advantages or disadvantages of one type of gear over the other?

Hey Chris

The main difference between a battery box and a preamp is the preamp amplifies and can in some cases attenuate a signal, and should also provide power to your microphones. A battery box does one main thing, it provides power to your microphones, some also have a bass roll off option. So if you have a box that boosts your input signal then its not a battery box its a preamp. In most cases a battery box is all that is needed. Some times like when you want to connect a mic into a DV camera mic jack you need attenuation, a preamp can do that if it has a gain control with a wide range from 00 or off to a +db setting of some known level.

I feel that a preamp with attenuation and boost provides the most flexible amount of use you can get. There are times when a battery box is not enough. Some times you need a preamp to boost the signal conversely sometimes you dont need any boost at all just unity gain, a fancy word for the level that comes into the device is the same as the level going out.

A battery box is all that is often needed with really loud concerts going into the line input on a MD for example. So a battery box will get you thru most things but a well designed preamp will get you thru everything your likely to encounter when recording live shows provided that the preamp in question will attenuate and boost with a flexible level control.

[Evil Taper]

A microphone pre-amp boosts mic level signal to line level signal.  Line level is the level that gear operates at, mic signal is much weaker.  So your battery box is basically a simplified pre-amp making your microphones loud enough to properly record with.  In general though when you're talking about mic pre-amps you're talking about a pre that is capable of supplying phantom power (+48v) to condenser microphones, they can't operate without it. 

If you're running dynamic mics you don't need phantom power, you just need a way to convert the mic level to line level and that's what your battery box is doing.  That's the most basic answer i can give you without going into tons of detail.  More questions just ask.

[Church-Audio]

A microphone pre-amp boosts mic level signal to line level signal.  Line level is the level that gear operates at, mic signal is much weaker.  So your battery box is basically a simplified pre-amp making your microphones loud enough to properly record with.  In general though when you're talking about mic pre-amps you're talking about a pre that is capable of supplying phantom power (+48v) to condenser microphones, they can't operate without it. 

If you're running dynamic mics you don't need phantom power, you just need a way to convert the mic level to line level and that's what your battery box is doing.  That's the most basic answer i can give you without going into tons of detail.  More questions just ask.

A battery box is not a simplified preamp its a simple power supply. There is no pre-amplification happening at all. Its providing power to the built in mic FET transistor of the electret mic capsule, but the battery box it self is doing nothing for your signal except allowing the FET to operate because its getting a bias voltage provided by the battery box.

A Dynamic mic does not need phantom that's correct. But it also does not need a battery box. You may need an impedance converter IE a transformer or active circuit to convert the low impedance mic to a hi impedance line input.

A battery box does not convert impedance at all. It simply provides power, To power a microphone.

[knoxmallette]

With a battery box you will increase gain with the pre-amp built into your MD. I have a battery box with levels & roll-off also but you can't get much gain boost from the levels. The levels will reduce gain pretty effectively. A pre-amp will boost gain and most will do it a lot cleaner than an MD's pre-amp. I believe the general rule is if you are taping loud shows a battery box is okay- if you are taping a quiet event and you need to crank up the gain then a pre-amp is what you need. In addition, some pre-amps will provide 9v to your mics so you kill two birds with one stone....

[evilchris]

if you are taping a quiet event and you need to crank up the gain then a pre-amp is what you need.

I think that essentially answered my question, even if in a round-about way.    Most of what I tape is loud rock show stuff, so I've never had a problem with the battery box configuration ... I do sometimes have to set my line input level to 25 or 27 out of 30, though, so I can easily see a quiet acoustic gig needing more of a boost.

Thanks!  I'd give you a +T, but I'm still too much of a n00b to have any to give.