newb 800 bright switch q

[Snickers Lamington]

hey guys,
never owned one of these (marshall 800), but ive noticed that the bright switch on V6 adds heaps of gain. is this how they normally work and whats the theory behind it?

im looking to get a MJ "black or white" kinda tone for a tune. am i in the right ballpark with this amp?
cheers

 

[HJM]

You always get a bit more gain with a bright switch on in any amp. The bright switch puts a capacitor in series with a resistor in the signal path at some point. The resistor could be fixed or a pot (ie vol/gain) depending on the amp. The audio signal passes freely through a capacitor but the capacitor will act as a filter, lower values let high frequencies through where higher values start to pass more mids and lows. As this HF portion of the signal bypasses the resistor you get more signal, hence more gain and in guitar amps you get more distortion. If its a very small cap you'll only hear the boost effect in the treble area.

I'd say Black and White could be a good candidate for tone matching!

 

[Thomas Larsson]

Yes !
That´s how it works .
The gain pot takes away gain as you lower it. You can then get back what you´ve taken away at a choosen freqency (bright cap interaction with taper value ).

That means that it sounds linear at full blast (switch won´t work) , and get´s thinner and thinner as you lower it (works more).