LPB needs more treble

[black mariah]

I finished up my LPB last night and had some time today to give it a thorough whipping. I dig the bass boost, but it doesn't seem to boost the treble much, if any. Is there a way to raise the amount of treble? Simple cap swap, I'm guessing, but to what values?

[zachomega]

Change the input cap...Take a look at the schematic for the screaming bird or a rangemaster to get an idea of the input and output coupling cap values they used. 

-Zach Omega

I finished up my LPB last night and had some time today to give it a thorough whipping. I dig the bass boost, but it doesn't seem to boost the treble much, if any. Is there a way to raise the amount of treble? Simple cap swap, I'm guessing, but to what values?

[amz-fx]

The low input impedance of the LPB is causing an interaction with the guitar pickups that is rolling off the treble...  you could put a buffer before the LPB to fix it.

http://www.muzique.com/lab/imp.htm

regards, Jack

[Yun]

Or add a tone control, man.  Like this for an example:




Keep in mind that any tone control is going to cut some boost, so just raise the value of the Volume pot....

[black mariah]

The low input impedance of the LPB is causing an interaction with the guitar pickups that is rolling off the treble...  you could put a buffer before the LPB to fix it.

http://www.muzique.com/lab/imp.htm

regards, Jack

Hrm... what kind of buffer are we talking about here? I thought the LPB was a buffer already.

[petemoore]

what kind of buffer are we talking about here? I thought the LPB was a buffer already.
  The LPB is a gain stage, higher voltage output than input.
  You'd be looking for a 'follower' or source follower [Jfet] or Emitter Follower {Bipolar].
  Good enough might be simply increasing the value of the base bias resistors?
  You might like the sound of a pre-buffered LPB, Jfet or HG/LN bipolar..either type would raise the Imp Imp plenty nuff for guitar or pedal as source. Jfet's easier, I was just reading about in GEO tech of Univibe.

[black mariah]

*head explodes*

Remove a resistor and change the transistor to a FET and it's a booster. Quick, to the perfboard!