What are Preamps? at DVinfo.net

Ben Hillier · October 17th, 2007, 07:47 PM

Sorry for stupid question, but, have searched with no joy....What are preamps and why would I want I good premap (in a mixer say) instead of straight to camera? Thanks.

Ty Ford · October 17th, 2007, 08:15 PM

Hello Ben,

Mics don't put out much electricity. They need a circuit to amplify their output. Thats a preamp. You can spend from $1.00 to over $1000.00 on a preamp. Depending on the mic you are using (and other stages after that) you may or may not notice the difference.

If you really can't hear well or make sense of what you're hearing, you probably won't be able to tell much difference.

Preamps in good mixers can make a noticeable improvement in your audio, but some cameras put line level mixer levels through their mic inputs by padding down the line level input to mic level and running it thorough the mic preamps on the camera anyway. WHY? Because i's cheaper than designing an input with separate mic and libne inputs.

Hope this helps.

Regards,

Ty Ford

Gerry Gallegos · October 17th, 2007, 08:23 PM

A pre-amp is an electronic device which gives either attenuation or amplification or both but not "both at the same time" to a signal actively (for amplification) and either passive or actively for attenuation before another active gain stage. do you need one? perhaps... if you need to boost or cut a mic's signal before it get to your camera's input. this depends on the source you are recording. if youre recording bird in the trees you might want one to raise the recording level of your microphone to match the recording level of your camera. if youre recording a live concert you might want to attenuate the signal before it get to your cameras input to reduce the chance of distortion. it is basically a way to control recording levels more accurately than the "auto gain " controls of your camera. a good preamp can raise levels alot quieter that your camera can (less hiss) and reducing the level on a loud signal with a preamp can make the auto gain adjust work less (therefore quieter) than with out.

Mark Utley · October 18th, 2007, 01:27 AM

Quote:

Originally Posted by Ty Ford

some cameras put line level mixer levels through their mic inputs by padding down the line level input to mic level and running it thorough the mic preamps on the camera anyway.

Something interesting I came across the other day:
http://www.sounddevices.com/notes/fi...h-line-inputs/

Ben Hillier · October 18th, 2007, 08:35 AM

Thankyou friendly people for your explantions....UNDERSTOOD!

October 17th, 2007, 07:47 PM	#1
Ben Hillier Regular Crew Join Date: Jun 2007 Location: Cali, Colombia Posts: 46	What are Preamps? Sorry for stupid question, but, have searched with no joy....What are preamps and why would I want I good premap (in a mixer say) instead of straight to camera? Thanks.

October 17th, 2007, 08:15 PM	#2
Ty Ford Inner Circle Join Date: Nov 2004 Location: Baltimore, MD USA Posts: 2,337	Hello Ben, Mics don't put out much electricity. They need a circuit to amplify their output. Thats a preamp. You can spend from $1.00 to over $1000.00 on a preamp. Depending on the mic you are using (and other stages after that) you may or may not notice the difference. If you really can't hear well or make sense of what you're hearing, you probably won't be able to tell much difference. Preamps in good mixers can make a noticeable improvement in your audio, but some cameras put line level mixer levels through their mic inputs by padding down the line level input to mic level and running it thorough the mic preamps on the camera anyway. WHY? Because i's cheaper than designing an input with separate mic and libne inputs. Hope this helps. Regards, Ty Ford __________________ Ty Ford's Audio Bootcamp Field Guide Ty Ford's Audio Video Blog

October 17th, 2007, 08:23 PM	#3
Gerry Gallegos Major Player Join Date: Oct 2007 Location: Houston, Texas Posts: 262	Preamp A pre-amp is an electronic device which gives either attenuation or amplification or both but not "both at the same time" to a signal actively (for amplification) and either passive or actively for attenuation before another active gain stage. do you need one? perhaps... if you need to boost or cut a mic's signal before it get to your camera's input. this depends on the source you are recording. if youre recording bird in the trees you might want one to raise the recording level of your microphone to match the recording level of your camera. if youre recording a live concert you might want to attenuate the signal before it get to your cameras input to reduce the chance of distortion. it is basically a way to control recording levels more accurately than the "auto gain " controls of your camera. a good preamp can raise levels alot quieter that your camera can (less hiss) and reducing the level on a loud signal with a preamp can make the auto gain adjust work less (therefore quieter) than with out.

October 18th, 2007, 08:35 AM	#5
Ben Hillier Regular Crew Join Date: Jun 2007 Location: Cali, Colombia Posts: 46	Thankyou friendly people for your explantions....UNDERSTOOD!