What is a preamp and what does it do?

I just googled "NuForce Icon HDP" and found this page of info at the NuForce website.

There it says the Icon HDP has a preamp output which makes sense to me. You question should be "What is a preamp output and what does it do?". :)

This will be what is often called a line level output. The signal level will not be altered by the gain (volume) control on the NuForce amplifier.

This is there so that you can connect the NuForce Icon HDP to, maybe, a Hi Fi system, something like that. That "preamp output" is a standard-ish level that is the same as the output from a source like a CD player or a Tuner or a DAC.

Historically those sources in a regular Hi Fi would be plugged into a preamp and then that would be connected to a power-amp which would drive your loudspeakers.

That separation of preamp and power amp has sort of been disappearing a bit. Often now you have amplifiers that simply do both tasks in one box, and in fact there is no separation in their circuitry between a preamp and a power amp.

The advantage of having that "preamp output" as Nuforce describe it is that you could use the DAC in the Icon HDP with a regular Hi Fi amp or a different headphone amp. I think that is useful and personally if I were getting the Icon I would get the HDP one.

I think that Nuforce might be better if they used the more commonly used "line out" description for that output.

Quote:

Originally Posted by p a t r i c k 

I just googled "NuForce Icon HDP" and found this page of info at the NuForce website.

 

There it says the Icon HDP has a preamp output which makes sense to me. You question should be "What is a preamp output and what does it do?". :)

 

This will be what is often called a line level output. The signal level will not be altered by the gain (volume) control on the NuForce amplifier.

 

This is there so that you can connect the NuForce Icon HDP to, maybe, a Hi Fi system, something like that. That "preamp output" is a standard-ish level that is the same as the output from a source like a CD player or a Tuner or a DAC.

 

Historically those sources in a regular Hi Fi would be plugged into a preamp and then that would be connected to a power-amp which would drive your loudspeakers.

 

That separation of preamp and power amp has sort of been disappearing a bit. Often now you have amplifiers that simply do both tasks in one box, and in fact there is no separation in their circuitry between a preamp and a power amp.

 

The advantage of having that "preamp output" as Nuforce describe it is that you could use the DAC in the Icon HDP with a regular Hi Fi amp or a different headphone amp. I think that is useful and personally if I were getting the Icon I would get the HDP one.

 

I think that Nuforce might be better if they used the more commonly used "line out" description for that output.

i dont understand this,.. it only makes sense to me if youv got a combo - a dac and amp in the same box, then i can understand why youd want a "pre-amp output", if indeed its just a line out for using just the dac. but why would anyone need it otherwise? whats the point of connecting a dac, into a pre-amp and from there to the power amp? why would i connect a line-out, into a different box, that also outputs a line-out?

Quote:

Originally Posted by adamlr 

i dont understand this,.. it only makes sense to me if youv got a combo - a dac and amp in the same box, then i can understand why youd want a "pre-amp output", if indeed its just a line out for using just the dac. but why would anyone need it otherwise? whats the point of connecting a dac, into a pre-amp and from there to the power amp? why would i connect a line-out, into a different box, that also outputs a line-out?

What NuForce describe as "pre-amp out" is I think possibly one of two things. It could be a "line out". This is standard-ish output level that is the same as the output from a CD player or a Tuner. The headphone volume control will not change the level of that output so you can plug it into an amplifier the same as you would a CD player. This means that you could use it as a DAC.

The standard setup in the olden times was:

CD player -> preamp -> power amp -> speakers

In this, the preamp will have a gain control. So, it takes a line level in, and outputs a variable level to the power amp.

So if you wanted to use the NuForce as a DAC it would go:

NuForce HDP -> preamp -> power amp -> speakers

Here you would use the "preamp out" connection if it is the standardised line level suitable for inputing to a preamp.

The other thing that NuForce HDP could mean by "preamp out" is not a line level output, instead the level is adjusted by the gain (volume knob) on the NuForce HDP, in which case they would intend it to drive a power amp directly. In that case the NuForce HDP would be behaving as a preamp.

Since my earlier post I am increasingly thinking it might be this second option because "preamp out" makes more sense as a name for that.

Which it is I don't know as I have no experience of the NuForce HDP.

Quote:

Originally Posted by p a t r i c k 

 

 

What NuForce describe as "pre-amp out" is I think possibly one of two things. It could be a "line out". This is standard-ish output level that is the same as the output from a CD player or a Tuner. The headphone volume control will not change the level of that output so you can plug it into an amplifier the same as you would a CD player. This means that you could use it as a DAC.

 

The standard setup in the olden times was:

 

CD player -> preamp -> power amp -> speakers

 

In this, the preamp will have a gain control. So, it takes a line level in, and outputs a variable level to the power amp.

 

So if you wanted to use the NuForce as a DAC it would go:

 

NuForce HDP -> preamp -> power amp -> speakers

 

Here you would use the "preamp out" connection if it is the standardised line level suitable for inputing to a preamp.

 

The other thing that NuForce HDP could mean by "preamp out" is not a line level output, instead the level is adjusted by the gain (volume knob) on the NuForce HDP, in which case they would intend it to drive a power amp directly. In that case the NuForce HDP would be behaving as a preamp.

 

Since my earlier post I am increasingly thinking it might be this second option because "preamp out" makes more sense as a name for that.

 

Which it is I don't know as I have no experience of the NuForce HDP.

 

 

 

 

but outside the hdp. why would i need a pre amp? whats the difference between the olden days, and today? if i had gain control anywhere but the amp, id put it at 100% and let the amp be my volume control. i dont get it... is a preamp just a way of getting more gain for speakers or something? is it like double amping?

Quote:

Originally Posted by adamlr 

but outside the hdp. why would i need a pre amp? whats the difference between the olden days, and today? if i had gain control anywhere but the amp, id put it at 100% and let the amp be my volume control. i dont get it... is a preamp just a way of getting more gain for speakers or something? is it like double amping?

In the olden days and still today I think, power amps don't have gain controls. If they have a gain control and input selector then they are usually called "integrated amplifiers".

The power amp is a box with one button for on and off. The gain control is in the preamplifier, along with a selector for input. Two descriptions would often be used for preamps, passive and active.

Passive Preamp

This is a box with a gain control and an input switching control. This needed no power at all. The passive preamp adjusted gain with a variable resistor, so it always went down.

Active Preamp

Active preamp manages gain using a circuit. This type of amp does have a power supply. Active preamps often contain an RIAA stage for a record player.

If you go to this webpage you will see a preamplifier and a power amplifier:

http://www.musicalfidelity.com/products/m8series/

Quote:

Originally Posted by p a t r i c k 

 

In the olden days and still today I think, power amps don't have gain controls. If they have a gain control and input selector then they are usually called "integrated amplifiers".

 

The power amp is a box with one button for on and off. The gain control is in the preamplifier, along with a selector for input. Two descriptions would often be used for preamps, passive and active.

 

Passive Preamp

 

This is a box with a gain control and an input switching control. This needed no power at all. The passive preamp adjusted gain with a variable resistor, so it always went down.

 

Active Preamp

 

Active preamp manages gain using a circuit. This type of amp does have a power supply. Active preamps often contain an RIAA stage for a record player.

 

 

If you go to this webpage you will see a preamplifier and a power amplifier:

 

http://www.musicalfidelity.com/products/m8series/

well that cleared it up entirely, cheers! thanks for the explanation =]