n00b alert: What is pre-amping?
Apr 1, 2006 at 11:14 PM Thread Starter Post #1 of 4

gsk3

New Head-Fier
Joined
Mar 13, 2006
Posts
30
Likes
10
Was playing around with the tube amp simulator in foobar and the pre-amp setting reminded me that I don't know what the heck pre-amping is. I assume it's a smaller amp that bumps up the signal before going into a larger amp in a speaker setup. I've never heard anything about pre-amping a headphones, except that I remember from a long time ago that a headphone amp is basically a pre-amp with a few modifications? Am I totally off here?
The bigger question is: why pre-amp? I assume for the quality, not the volume (can't imagine a larger amp couldn't get the signal to where you want it.

Thanks,
Ari
 
Apr 1, 2006 at 11:29 PM Post #2 of 4

hciman77

Headphoneus Supremus
Joined
Feb 25, 2004
Posts
2,890
Likes
12
The term pre-amp has a number of different meanings depending on the context.

In the old days amplifiers mostly consisted of two parts - a pre-amplifier (or control amplifier) and a power amp. The pre-amp had all the inputs, volume and tone controls and output a signal to the power amp which then applied more power to the signal and output it to the speakers. The power amp applied a fixed amount of amplification and the pre-amp determined the size of the signal it received. My understanding was that the pre-amp here cut the signal down from the full 1 - 2 V rather than amped it up - but I may be wrong on this

To confuse things not all inputs are line level - turntable cartridges output a very small signal with a really naff frequency response - to get a listenable sound you have to apply a eq to the cartridge signal - the infamous RIAA curve - the old pre-amps would have a dedicated eq and step-up circuit for this. Many modern amps however do not cater for turntable inputs so you sometimes need another pre-amp for the phono input.

As for software pre-amps - the metaphor breaks down here.
 
Apr 2, 2006 at 1:46 AM Post #3 of 4

gsk3

New Head-Fier
Joined
Mar 13, 2006
Posts
30
Likes
10
Thanks. Makes much more sense now.
Ari

Quote:

Originally Posted by hciman77
The term pre-amp has a number of different meanings depending on the context.

In the old days amplifiers mostly consisted of two parts - a pre-amplifier (or control amplifier) and a power amp. The pre-amp had all the inputs, volume and tone controls and output a signal to the power amp which then applied more power to the signal and output it to the speakers. The power amp applied a fixed amount of amplification and the pre-amp determined the size of the signal it received. My understanding was that the pre-amp here cut the signal down from the full 1 - 2 V rather than amped it up - but I may be wrong on this

To confuse things not all inputs are line level - turntable cartridges output a very small signal with a really naff frequency response - to get a listenable sound you have to apply a eq to the cartridge signal - the infamous RIAA curve - the old pre-amps would have a dedicated eq and step-up circuit for this. Many modern amps however do not cater for turntable inputs so you sometimes need another pre-amp for the phono input.

As for software pre-amps - the metaphor breaks down here.



 
Apr 2, 2006 at 1:15 PM Post #4 of 4

john_jcb

This is a customized witticism.
Joined
Mar 27, 2002
Posts
5,684
Likes
14
Quote:

Originally Posted by hciman77
The term pre-amp has a number of different meanings depending on the context.

In the old days amplifiers mostly consisted of two parts - a pre-amplifier (or control amplifier) and a power amp. ...........................



This is still how it works
icon10.gif
. Most often both units are housed in one enclosure and it is referred to as an integrated amp. Many higher end setups still keep the two separate.
 

Users who are viewing this thread

Top