3 Sep
2008
3 Sep
'08
9:56 a.m.
William Donzelli wrote:
Can't get much cheaper than effectively free for a well regulated, high current DC
power supply using a modified PC power supply that isn't otherwise being used. Plus,
the idea of using tubes with 5V filaments instead of 6.3/12.6V reduces the competition
with typical audio tube customers and makes the use of a high-current 5VDC supply
possible. For the homebrew 1.5A adjustable DC supplies, I use LM317HV based units plugged
into a homebrew chassis where I've mounted a range of three different inexpensive,
surplus, multi-secondary transformers with output voltages ranging from 70VCT to 12.6VCT.
The chassis has binding posts for each secondary and I just plug the banana plugs for the
various inexpensive LM317HV adjustable DC supplies into whatever AC outputs most closely
match the DC voltages I need at the time in order to reduce the power dissipation
requirements of the LM317HVs.
I've got
several homemade variable DC supplies,
but they are all limited to 1.5A output
which would be
exceeded with just three 5BK7A filaments @ 600mA each.
An old filament transformer would solve all your problems
in this area. Not expensive.