http://phonestack.com/farhan/dc40.html

here's a nice and easy 40m DC receiver.All are "popcorn" parts.Uses only 5 BJT 2n3904/2n2222 transistors and 1 MPF102.You will have to do some math to figure out the inductances on "normal" toroids.And use FT37-43 for the mixer(approx. 12 Trifilar turns??).

Most DC designs use Ne602/LM386.I think a beginner should use discrete parts first.

73 de va7aax