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ST-35 Heaters
Posted:
Thu Apr 12, 2012 12:41 pmby johnf
Hello,
Do I need to use the dropping resistors (0.5 Ohm) in the heater circuit. I have Trafomatic transformers. I specified 6.3v when I ordered them. Do these serve any other purpose than to drop the voltage of certain other tranny's? Thanks in advance.
Posted:
Thu Apr 12, 2012 1:13 pmby jgf
You might, it depends on your line voltage and what you're drawing as a load. Maybe build without the dropper resistors first, measure your heater voltage, then calculate what you need to dial in the exact 6.3 volts. Too high voltage is said to decrease tube life.
Posted:
Fri Apr 13, 2012 12:21 pmby johnf
OK Thanks. I have the 0.025 Ohm resistors on the board (one either side). What is the voltage drop across these? Is it worth removing them?
Posted:
Fri Apr 13, 2012 12:38 pmby TomMcNally
When you fire the amp up, measure the filament voltage AT a tube.
If it's lower than 6.1 or so ... short across the resistors with wire.
No need to remove them.
You'll like the diytube ST-35 ... I have mine playing here in the
office now.
Eric Clapton, Lay Down Sally on WSNQ, Cape May Court House, NJ