[Elecraft] The audio filter

[WA2JJH at aol.com]

The two blue pots on the audio filter seem to offer a great range of audio  
filtering.
However with the pots and software, I cannot get on effect I want.
 
  It might be impossible to do even if I mod it. I simply want to  lower the 
noise floor.
The noise floor is low. However I wanted to try to get it to sound like a  
TR-7's noise floor.
Perhaps I should consider the DSP kit/up grade?
 
  My chip on my audio filter is a rev one. Is there a firmware update?  Or is 
this chip limited to how much it can do with the multiple op-amp  chip?