# DIY Bass Guitar Practice Headphone Amp - Add preamp to Cmoy?



## rodgersk24

Hello,

 I just moved into a new apartment and have been getting complaints about playing bass with any sort of volume at all through my amp. So, I'd like to build a little headphone amp to use. In addition, I'm trying to learn how to read circuit diagrams, so I thought it'd be a fun project to work on.
   
  A Cmoy headphone amp was recommended to me, but I read on the Tangent Soft website that a preamp should be added to the Cmoy for it to work with passive basses (and guitars in general).
   
  Does anyone have a preamp diagram that has worked for them with the Cmoy in the past, or even better, one that's worked for a bass or guitar practice headphone amp?
   
  I'm very new to building circuits, and this will be my first project, so please go easy on me.  I feel reasonably confident that I can read a diagram ok, but if someone has a preamp diagram that marks where the input comes in and where the output exists to the power section that would be excellent.

 Thanks in advance for the help, and thanks in advance for putting up with possibly dumb questions from a new circuit builder!

 Best wishes,

 Kyle


----------



## Fred_fred2004

This works very well, Replace the 47n cap on the fet ouput with a 470n for better bass. and use a stereo input socket as a switch (short out ring and sleeve to connect gnd)

   
  cheers
  FRED


----------



## FLACm0nkEy

Quote: 





fred_fred2004 said:


> This works very well, Replace the 47n cap on the fet ouput with a 470n for better bass. and use a stereo input socket as a switch (short out ring and sleeve to connect gnd)
> 
> 
> cheers
> FRED


 
  I used to use an LM386 based headphone guitar amp and I have to say that they don't sound half bad and with high gain you can even get some nice clipping going for a good crunch.
   
  Here is a much simplified schematic:

  I believe the gain is set on max in this schematic so you would get quite a bit of distortion, use a pot like in the previous schematic between pins 1 and 8 to control your gain.
  I suggest you get a breadboard and try a few different component combinations out to see what kind of sound you like most.
  Good luck!


----------



## Fred_fred2004

Quote: 





fred_fred2004 said:


> This works very well, Replace the 47n cap on the fet ouput with a 470n for better bass. and use a stereo input socket as a switch (short out ring and sleeve to connect gnd)
> 
> 
> cheers
> FRED


 



   
  this is a perf board version, it might help
   
  cheers
  FRED


----------

