If you are going to build this mic-pre, I recommend reading the "Mu Stage Philosophy" article.

micpre.gif (9567 bytes)
  

Download the printed circuit board layout    (a zipped tif)
 


Here is the parts layout and stuffing guide. ( top view)
 



 


 
     Below is a bad picture of a stereo pair built into an open-frame wooden enclosure. I like the tubes exposed because it is easy to change them. The mic transformers are inside the case along with  a switch for 6 or 12 volt filaments. I have pairs of 6FQ7, 6922, 12AY7 and 12AU7s. Each of these tubes gives the preamp a different sonic signature.
      

micprepic.jpg (25497 bytes)

        
Here is the power supply, a small transformer for phantom power is inside the case.
           

mppower.jpg (17373 bytes)