Step 5: Parts!
Here are the parts that I used, and the approximately how much each one cost:
~$30 (2) 811A Vacuum Tube Triodes
~$0 (1) Microwave Oven Transformer
~$10 (1) 30kV 1.0nF Polystyrene Capacitor (2 or 3nF will also work here, I found that larger capacitance increased the performance slightly)
~$15 (1) Bundle of 1000 ft. of 28 AWG Magnet Wire
~$10 (1) Bundle of 100ft. of 16 AWG Insulated Audio Wire (Can be purchased from Radio Shack)
~$3 (2) Small Circuit Boards
~$10 (1) 1' x 1' x 1" Wooden Board (This price is for about 10 of these boards)
~$5 (1) Box of Nails
~$0 (2) Ferrite Toroid Cores (Should be at least about 1/2" in inner diameter, these are not critical parts)
~$2 (4) 3kV 1.8nF Ceramic Disk Capacitors
~$10 (1) 50W 5k� Resistor (� = Ohm Symbol)
~$7 (2) 20W 30� Resistors
~$0 (1) 6.3 VAC 10A Filament Transformer (You can use 5 volts from a modified computer power supply instead if you want to save some money, but the performance will decrease)
~$5 (1) Small Container of Epoxy Glue (This is for gluing the secondary coil down, if you want to experiment (like me) then you shouldn't glue the coil down)
~$5 (1) 1' of 4" Diameter PVC Pipe (Primary Former)
~$3 (1) 1' of 2" Diameter PVC Pipe (Secondary Former)
Total: ~$100
This is actually a very crude estimate, and shipping costs will differ depending upon where you buy from and where you live. The parts marked $0 were either salvaged (like the Microwave Oven Transformer) or they were free samples (like the Ferrite Toroid Cores) or were already owned (I used a computer power supply instead of a costly filament transformer).
~$30 (2) 811A Vacuum Tube Triodes
~$0 (1) Microwave Oven Transformer
~$10 (1) 30kV 1.0nF Polystyrene Capacitor (2 or 3nF will also work here, I found that larger capacitance increased the performance slightly)
~$15 (1) Bundle of 1000 ft. of 28 AWG Magnet Wire
~$10 (1) Bundle of 100ft. of 16 AWG Insulated Audio Wire (Can be purchased from Radio Shack)
~$3 (2) Small Circuit Boards
~$10 (1) 1' x 1' x 1" Wooden Board (This price is for about 10 of these boards)
~$5 (1) Box of Nails
~$0 (2) Ferrite Toroid Cores (Should be at least about 1/2" in inner diameter, these are not critical parts)
~$2 (4) 3kV 1.8nF Ceramic Disk Capacitors
~$10 (1) 50W 5k� Resistor (� = Ohm Symbol)
~$7 (2) 20W 30� Resistors
~$0 (1) 6.3 VAC 10A Filament Transformer (You can use 5 volts from a modified computer power supply instead if you want to save some money, but the performance will decrease)
~$5 (1) Small Container of Epoxy Glue (This is for gluing the secondary coil down, if you want to experiment (like me) then you shouldn't glue the coil down)
~$5 (1) 1' of 4" Diameter PVC Pipe (Primary Former)
~$3 (1) 1' of 2" Diameter PVC Pipe (Secondary Former)
Total: ~$100
This is actually a very crude estimate, and shipping costs will differ depending upon where you buy from and where you live. The parts marked $0 were either salvaged (like the Microwave Oven Transformer) or they were free samples (like the Ferrite Toroid Cores) or were already owned (I used a computer power supply instead of a costly filament transformer).
Remove these ads by
Signing Up
Visit Our Store »
Go Pro Today »
At the moment, I would strongly recommend upgrading to a 572B tube - it's a drop-in replacement the 811A and solves the plate reddening problem.
Good luck!
Try local hamfests/electronics events - I got a few American-made 811A and 572B tubes at Swapfest in Cambridge MA near MIT.