How does fixed line level attenuation work?

[ohms]

hello all

first post here and I'm interested in some info you people may hold

in layman's terms I'm trying to understand how a fixed line level can attenuate.
according to wikis line level page the 'the signal out or line out remains at a constant level, regardless of the current setting of the volume control', i understand the statement but not the engineering behind it i.e how you attenuate a signal that is fixed

hope you can shed some light here

regards

 

[CWatters]

You don't, they aren't talking about the same signals.

Typically a hifi system will have several outputs. For example there might be speaker outputs, line outputs, headphone outputs etc Each output is intended to be connected to a different type of device. Some systems will even have digital outputs, perhaps capable of streaming the signal to a network.

Normally if the system has a volume control it only affects the speaker outputs but sometimes they are designed to affect other outputs as well. Normally the line output is not affected by the volume controls.

Here is a block diagram..

http://www.kpsec.freeuk.com/images/audio.gif

Although not shown on the diagram the line output would be connected after the preamp but before the tone and volume control block. A Line Input might also be provided and this would also be connected at this point.

 

[CWatters]

PS. I've looked for a better block diagram online but to my surprise I've not been able to find one showing a traditional hifi amplifier.