6,3 VAC heater power supply question

[thekid777]

Hi,
I need to power one mic pre which needs 6,3 VAC for the heater,
there's a way to have this regulated and even filtered like most VDC supply or it can't as it is VAC?

Thanks!

 

[joaquins]

Heaters can take quite a bit of abuse, ±20% won't hurt them, of course if you can have them on the low side much better so tubes will last forever.

You could use 6.3V DC regulated, or 6V regulated will be fine, just a 7806 if the current needs aren't too high.

In both cases you should take some care to avoid noises, with the AC you can trim a center tap with a resistive divider to cancel hum. With DC you should be really careful about the noise of the rectifiers, cap surges and the ripple. If it isn't a very high gain preamp you may be better off with AC, much simpler to deal with.

JS

 

[thekid777]

Thanks J!

 

[dmp]

there's a way to have this regulated and even filtered like most VDC supply or it can't as it is VAC?

The heater in a tube is like a light bulb - it is spec'd as a voltage, but the power is the important factor to properly heating the tube - so if it is AC or DC, the power should be the same. Conveniently, AC voltages are specified as RMS, which means the power of AC voltage is equal to the power of DC voltage through the same resistance.