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To Variac or not to Variac ....?

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Sir Thrift-a-Lot:
As I understand it, a dim bulb doesn't exactly replace a variac, but does add some insurance.   A dim bulb will let you know if there is an issue and buffer the potential damage, but it won't reform the caps like a variac would.   I've heard some people say that five minute power cycles once an hour or so, first on the variac for a few hours then without it for a few hours will help to reform the caps, but I don't know if that is actually true or just urban legend.   It seems reasonable to me, though.

schwarcw:
You could buy a Variac online for $100 or less.  Might save you gas money and paying somebody to do it.

bmwr75:
A dim bulb tester and a variac do not serve the same purpose. 

A DB tester is for determining if something is shorted in an amp.  It a short exists, the bulb will burn brightly continuously (no source or speakers connected).  If no short exists, the bulb will burn brightly while the power supply capacitors charge up (usually a few seconds) and then it will dim down to no visible light or a very dim light.  Of course the wattage bulb used in the DB tester makes a difference too.  I usually used one in the 75 watt range for most amps.

A variac is used to slowly bring the voltage up to an amp and allow the capacitors to reform slowly.  It will do nothing to prevent you from frying electronics if a short exists in the amp.

steinjw:
bmwr: Yes, that is what I recalled regarding the dim bulb - serves more of a warning to "get out now" if things are not proceeding as they should, but doesn't serve the purpose for the variac power-up.

schwarcw: Oh great - now I must persuade "someone" that I need to purchase another $100 tool - got a tried and true script for that?

All comments are appreciated - thanks.

MacGeek:

--- Quote ---schwarcw: Oh great - now I must persuade "someone" that I need to purchase another $100 tool - got a tried and true script for that?
--- End quote ---

This is like Paul Simon's 50 Ways to Leave your Lover.

 You can sneak it in the house. I know I have enough tools no one will ever know if I add one more. If that won't work, hid it.  No one knows what is in the trunk of my car.

Lie about the price.  I have a friend who always told his wife the price for anything he bought was about 1/2 of what he actually paid.

Cut a deal.  Something for her and something for you (this generally works for me and while I might hide something, I don't like lying).

I don't know what the consequences might be, but you can always just do it and take the heat.


 

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