[GreenKeys] Off topic: variable transformer

[Jeffrey D Angus]

On 7/27/2016 10:09 PM, Paul Heller wrote:
> I have some electronic and computing equipment that I want to
> safely power up. I'd like to use a variable transformer. Can
> anyone recommend a particular model to buy?
My recommendation: None.

This a bad idea despite what you've been told.
With regards to vacuum tube gear, there will NOT be enough filament
voltage on the rectifier tubes to conduct until you reach 80-90 VAC on
the variable transformer. Then you will "hit" the equipment with 60 to
70% of full B+ voltage. However, anything that requires the correct B+
and any biasing voltages is going to be way off.

If you're doing this to "reform" electrolytics, you're wasting your time.
They're either good or bad, if the "reform" then they'll probably fail
shortly afterwards. Electrolytic capacitors are cheap. The stuff they
damage when they fail are not.

One "computer gear" what ever that means.
If they have old linear power supplies, the voltages are going to be
way off until you hit a certain percentage of the line voltage. Having
wrong or miss-matched voltages is a bad idea.
On the other hand, if they are switched mode supplies, they tend to
set fire to themselves when they don't have the right voltages on the
inputs.


-- 
Jeff-1.0
wa6fwi
http://www.foxsmercantile.com