by Vapour » Tue May 19, 2015 6:02 pm
Finishing up on this amp, & been testing the heater circuit. It's a little high as tested, so just a question or two.
AC heaters measure 6.7Vac.
So I need to add resistance to the Ac heater inputs, how much though? Came across the formula: R = Vactual - Vdesired/2 x Ih .
Heater current for the rectifier + 6A3 gives R = 6.7-6.3/2x(1.2+1.0) = 0.1Ω
For the 6SL7 + 6A3 gives R = 6.7-6.3/2x(0.3+1.0) = 0.15Ω.
If I'm doing this correctly, would a 0R12 resistor be a good compromise?
Edit (a week later): added a 0R15 resistor each side & voltages now good. Thanks for all your help.