Brightness switch on Laney Lionheart / VC amps

[andrius]

I'd like to know what exactly does the Bright switch do on Laney Lionheart or VC series amps (schematic of Lionheart attached).
Most other amps don't have anything like a Bright switch, so I wonder whether the "normal" (that is like other amps brightness-wise) would be when the switch is on or off. I mean, whether it is as bright as other amps when the Brightness is switched off or on. It is hard to do a fair comparison for me, partly because the Tone control is screwed up so that I don't really know where is the "neutral" setting on it - so maybe someone with electronic knowledge (and maybe experience with these amps) would be able to answer the question.

Also, I think I hear that Bright switch makes the difference when on the Drive channel with low gain, but when more gain, it seems the effect of it becomes less apparent (if apparent at all). Why is that?

Laney L5T-112 (lionheart) schematic.pdf

[Enzo]

Tons of amps have bright switches. A zillion Fenders have them on their control panels.

This amp has the classic bright switch. All it is is a cap that switches in, and the cap bypasses the volume control with come of the high end. If you look at the schematic, see that when the switch is closed, the cap becomes conneted from the top terminal of the volume control to the wiper of the control.

Now think about it. When the volume is all the way up, the wiper of the control is right up against the top terminal, so the cap is effectively shorted across by the control. SO at max volume, indeed the brigth switch has no effect. SInce high frequencies can flow through that cap, but not bass sounds, they can bypass the volume setting. SO when volume is half way up, the highs are relatively unimpeded, so the sound is brighter. Obviously all the way down, you get no sound at all, so at mid volume settings the bright switch has the most effect.

Get rid of any notions that a guitar amp is a hifi amp, or that it is flat in response at all. They are neither of these things. There is no neutral on a guitar amp. The bright switch should make the sound brighter when it is on than when it is off. The tone controls make the sound more or less bright or bottomy or whatever. The question to ask yourself is "can I get a tone I like from this amp?" COmparing two amps, you could set all the tone controls to 5, but that isn;t really flat, all that is is the mid point on each control. And if you did set all teh controls to the middle, if one amp is brighter than the other, OK, the question then is merely, can I adjust the controls and get something I like. It really doesn;t matter if one amp sounds best with the treble on 5 and another amp on 7.