I am looking at DC heaters for a phono section and have a few questions.
1. I think it would be more convenient for me to use series string heater arrangement (4x12AY7). Is there any reason that this would not be advisable v.s. parallel heaters?
2.Would it be wise to have a polarity switch to reverse current every "X" hours for even heater wear?
3. Even though the current is DC would it be a good idea to twist the leads to reduce EMI getting into the heater circuit?
4. Does it matter whether one uses 12 or 6V wiring?
1. I think it would be more convenient for me to use series string heater arrangement (4x12AY7). Is there any reason that this would not be advisable v.s. parallel heaters?
2.Would it be wise to have a polarity switch to reverse current every "X" hours for even heater wear?
3. Even though the current is DC would it be a good idea to twist the leads to reduce EMI getting into the heater circuit?
4. Does it matter whether one uses 12 or 6V wiring?
I power all my 6V tubes in pairs from 12VDC. I never switch the polarity (might be an idea in directly heated tubes) and it works fine.
I twist the wires because they look nicer and stay dressed easier but I've also used single wire power and chassis for return with good results.
As far as 6 vs 12 volts? What's easier to find? 24V or 48V? 🙂
I twist the wires because they look nicer and stay dressed easier but I've also used single wire power and chassis for return with good results.
As far as 6 vs 12 volts? What's easier to find? 24V or 48V? 🙂
It is indiferent. Heater is a simple resistance and has no polarity.
In any case, check that leackage between filaments and cathodes naturally increases as voltage gradient do. So, if cathodes are close to ground, it is irrelevant but if you use active loading, the upper tube leackage can affect amplifier tube in some way. Take into account also capacitances.
In any case, check that leackage between filaments and cathodes naturally increases as voltage gradient do. So, if cathodes are close to ground, it is irrelevant but if you use active loading, the upper tube leackage can affect amplifier tube in some way. Take into account also capacitances.