maxwall
Well-known member
- Joined
- Nov 17, 2004
- Messages
- 1,134
Easy tube microphone power supply for 12AX7 or 12AT7 tube mics and more. easily modified to other voltages.
-filament linear regulated (78xx), HT Linear regulation using BUX 85 power transistor.
-easy self etch board design
-low cost
Power Transformer :
primary 230 or 115 vac
Secondary 1 12-16 vac .6-1amp,
Secondary 2 120-133vac 20-30ma
Note : Two separate transformers can be used in series. Pri 115 or 220vac :12vac 6va and 9-12vac : 220vac Secondary. 3-6va
construction notes:
BUX 85 NPN power transistors base must be heat sink mounted with insulator and white heat sink compound. Use
of teflon plastic insulated washers recommended to prevent component short to ground.
7812 Filament regulator does not require insulator between the component base and heatsink.
power supply can be modified with a 7806 filament regulator and a change to 12vac secondary power transformer for use with tubes requiring 6 vdc filament voltage. examples are 6922, 6072, 6205, 5840 etc ... depending on application , keep in mind a 6 vdc filament may require double the current (.300ma min ) of the 12vdc filament (.150 ma ). consult your tube datasheet for filament requirements.
1N5380B - 5W , 120v zener , (B) 5% tolerance - Mount this zener so its spaced above board for cooling.
Post your results
-filament linear regulated (78xx), HT Linear regulation using BUX 85 power transistor.
-easy self etch board design
-low cost
Power Transformer :
primary 230 or 115 vac
Secondary 1 12-16 vac .6-1amp,
Secondary 2 120-133vac 20-30ma
Note : Two separate transformers can be used in series. Pri 115 or 220vac :12vac 6va and 9-12vac : 220vac Secondary. 3-6va
construction notes:
BUX 85 NPN power transistors base must be heat sink mounted with insulator and white heat sink compound. Use
of teflon plastic insulated washers recommended to prevent component short to ground.
7812 Filament regulator does not require insulator between the component base and heatsink.
power supply can be modified with a 7806 filament regulator and a change to 12vac secondary power transformer for use with tubes requiring 6 vdc filament voltage. examples are 6922, 6072, 6205, 5840 etc ... depending on application , keep in mind a 6 vdc filament may require double the current (.300ma min ) of the 12vdc filament (.150 ma ). consult your tube datasheet for filament requirements.
1N5380B - 5W , 120v zener , (B) 5% tolerance - Mount this zener so its spaced above board for cooling.
Post your results
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