# Twin face mods



## mastermachetier (Feb 27, 2021)

Hello All,

I wanted to be able to have a knob for tone and a knob for bias . I was wondering if someone could point me in the right direction as to how to add these mods to the twin face !

thanks


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## JamieJ (Mar 4, 2021)

You can use a 10k pot in place the bias trimmer. You would need two knobs if you wanted both externally biasable. There are loads of tone control options such as a big muff type tone control at the output. That will weaken your signal though.


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## Chuck D. Bones (Mar 6, 2021)

What you do for tone controls really depends on what you want it to sound like.  Are you try to take off some of the highs or???  As JamieJ said, tone controls will eat some of the signal.  There are mods to recover the lost volume.


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## JamieJ (Apr 10, 2021)

mastermachetier said:


> Hello All,
> 
> I wanted to be able to have a knob for tone and a knob for bias . I was wondering if someone could point me in the right direction as to how to add these mods to the twin face !
> 
> thanks


https://shop.pedalparts.co.uk/Big_Muff_Pi_Tone_Stack/p847124_19032653.aspx

This can be wired as a passive BMP tone control or you can also add the volume recovery part of the circuit. There is also an optional mids control which could be a trim pot. Looks cool. I’m tempted to give it a go on my next FF build.


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