Does Preamp increase the max volume?

[iBug]

I owned a power-amp of Rotel for 5 years and I didn't have a pre-amp, I was changing the volume within my DVD player, it had a volume control ranging from -80 dB to 0 dB. And when it was at 0 dB, the volume was loud enough. Then I bought a pre-amp from Rotel a week ago, and now when I maximize the volume on the Pre, the amound of volume coming from the speakers is a lot louder than before (DVD player at 0 dB again). How does it happen? Does the Pre add more dB or what?

[Geoffcin]

I owned a power-amp of Rotel for 5 years and I didn't have a pre-amp, I was changing the volume within my DVD player, it had a volume control ranging from -80 dB to 0 dB. And when it was at 0 dB, the volume was loud enough. Then I bought a pre-amp from Rotel a week ago, and now when I maximize the volume on the Pre, the amound of volume coming from the speakers is a lot louder than before (DVD player at 0 dB again). How does it happen? Does the Pre add more dB or what?

Yes, an active preamp is an line level amplifier. You will get a lot more gain from it than just the standard componant line level. You will however NOT get any more power from your amp, so be careful not to overdrive it!

[skeptic]

Think of the preamp volume control as the throttle for an engine. Changing the throttle won't change the amount of power available. But a one throttle might make your car fly with the slightest push of the gas pedal while another throttle might require you to push it nearly all the way to get going. If you have inadequate signal to drive your amplifier to its full power output such as might be the case with a passive preamplifier or a moving coil cartridge and a preamp with insufficient gain, it's like having a throttle that just won't go far enough.

While having a preamp where the slightest turn of the volume control produces very loud sound may give you the illusion of having a powerful amplifier or having a car where the slightest push of the gas pedal sends you flying may give you the illusion of having a very powerful engine, it isn't necessarily so and after the novelty of it wears off, you realize that you have relatively poor control over all the power you do have which is not a very satisfactory arrangement.

[spacedeckman]

Okay, standard maximum output for a device such as a CD, DVD, Cassette, or anything else but a phono is supposed to be around 2 volts. In reality, it can be a bit higher or lower. A pre-amplifier will be capable of 5-20 volts or more. What it does is make the signal going to the amplifier potentially a bit larger. However, you control that with the volume control. So, a pre-amp is supposed to provide a better signal into the amplifier by allowing more voltage swing than the source plugged into it.

As was mentioned before, this will not increase the output capbility of the amplifier unless the source component was not able to get enough voltage to the amplifier to get maximum volume. An amplifier can do what it can do, and their is no way to make it do more. If you want more out of it, you buy more sensitive (efficient, as it is often improperly called) speakers, which may provide other tradeoffs.

In summary, it probably isn't going to get you more, but it will probably get you noticably better due to output capabilities of your source which are usually not too good.