ForthMonkey
Well-known member
I found some Fairchild schematics.Solid-state and easy schematics.Made di-box.And now making preamp.
I will make some 692 modules.
Think it as gain module.22dB to 52dB.Changed original transistors.Breadboarded it and working well.To make it mic pre,need 1:5 transformer and mic pre front end.
Original schematic
https://dl.dropboxusercontent.com/u/91809016/Fairchild%20692/Fairchild_692AA.pdf
I made selectable input and output transformers.
If you want to use it with only one transformer,do not install Control Board.Just use simple frontend.And use RZ and CZ components to make zobel.
If you use all transformers,do not install RZ and CZ.Install seperate zobels to directly transformers's pins.
Single sided self etch files...
PRE BOARD
Schematic
https://dl.dropboxusercontent.com/u/91809016/Fairchild%20692/PRE_SCHEMATIC.pdf
Bottom
https://dl.dropboxusercontent.com/u/91809016/Fairchild%20692/PRE_BOTTOM.pdf
Layout
https://dl.dropboxusercontent.com/u/91809016/Fairchild%20692/PRE_LAYOUT.pdf
CONTROL BOARD
Schematic
https://dl.dropboxusercontent.com/u/91809016/Fairchild%20692/CONTROL_SCHEMATIC.pdf
Bottom
https://dl.dropboxusercontent.com/u/91809016/Fairchild%20692/CONTROL_BOTTOM.pdf
Layout
https://dl.dropboxusercontent.com/u/91809016/Fairchild%20692/CONTROL_LAYOUT.pdf
I will make some 692 modules.
Think it as gain module.22dB to 52dB.Changed original transistors.Breadboarded it and working well.To make it mic pre,need 1:5 transformer and mic pre front end.
Original schematic
https://dl.dropboxusercontent.com/u/91809016/Fairchild%20692/Fairchild_692AA.pdf
I made selectable input and output transformers.
If you want to use it with only one transformer,do not install Control Board.Just use simple frontend.And use RZ and CZ components to make zobel.
If you use all transformers,do not install RZ and CZ.Install seperate zobels to directly transformers's pins.
Single sided self etch files...
PRE BOARD
Schematic
https://dl.dropboxusercontent.com/u/91809016/Fairchild%20692/PRE_SCHEMATIC.pdf
Bottom
https://dl.dropboxusercontent.com/u/91809016/Fairchild%20692/PRE_BOTTOM.pdf
Layout
https://dl.dropboxusercontent.com/u/91809016/Fairchild%20692/PRE_LAYOUT.pdf
CONTROL BOARD
Schematic
https://dl.dropboxusercontent.com/u/91809016/Fairchild%20692/CONTROL_SCHEMATIC.pdf
Bottom
https://dl.dropboxusercontent.com/u/91809016/Fairchild%20692/CONTROL_BOTTOM.pdf
Layout
https://dl.dropboxusercontent.com/u/91809016/Fairchild%20692/CONTROL_LAYOUT.pdf