db scale volume on higher-end receivers

[Chevypower]

I'm not sure if any of you have thought about this, or I am just stating the obvious, but I was a little confused as to why some receivers have volume markings from - infinity db through 0db (which can be awfully loud) to about +18db. After doing it on a pre-amp, I realized 0db was about the same as just coming straight out of a stereo RCA line out on the back of the Blu Ray player, so anything below 0db is lower than line level in the pre-amp and anything more, is cranked up that little bit extra. So on a full amplified receiver, the volume is not adjusting the amplifier, but is adjusting the pre-amplified signal?

[airkitty]

Ok - the volume control is a resistor or potentiometer(?). The negative numbers say something about the amount of resistance offered the signal before amplification to the speakers. 0 = no resistance or W.F.O. The normal output of solid state home equipment is 2v (fixed). So if your receiver/pre amp are set at 0 or W.F.O. then your amp section is using all the signal available from the source equipment for it's maximum amplification potential.

[richteer]

Originally Posted by Chevypower

So on a full amplified receiver, the volume is not adjusting the amplifier, but is adjusting the pre-amplified signal?

Right; the volume control is adjusting the amount of attenuation or gain the preamp applies to the signal before "feeding" it to the power amp.

[Chevypower]

cool thanks for that.

[welwynnick]

With regard to integrated amps, the dB scale can say what it wants, but in theory it can have two meanings.

The first is that a max line level input signal of 2V will result in full output power from the amplifier. This is not as simple as it sounds because that output power varies with the number of channels benig driven, so its not exact.

The other meaning is reference level, which is used for audio calibration. Reference level on the disc should then correspond to reference level in the room. Of course, this depends on the efficiency of the speakers and the physics of the room, and these vary greatly.

Either way, 0 dB is effectively "maximum", but its not exact. The scale goes to positive values so that quiet passages can be made louder, should anyone want to risk their ears or speakers.

[ozzman]

You know thats the way i always looked at it,but it's nice to see someone addressing the question.

Thanks for the small thread and the replies