variac hum & vibration

[tomrasdf]

I'm in the process of powering up my first non-kit build. The amp has been doing great with voltages being where they need to be, but I'm struggling with my variac.

It worked for a while ar first, then it blew breaker on the outlet. This was when there was nothing plugged into the variac and with the power set at 0. I plugged it in again, this time with the power turned up a bit and everything's kosher.

There is, howerver, and was from the begining (before it started blowing the breaker) very faint vibrations eminating form the variac and a very faint hum, even with no current running through it. Where does one go from here? I've used the variac plenty of times before with no problem. I'm renting a house for the rest of the semister and the wall puts out 133v. Unless I turn it down, it turns my innocent little 5f1 into a power tube-arching monster. I guess my question is, should I turn my variac into a boat anchor and start saving up for a new one of should I be alright?

Thanks in advance. This forum has been an amazing resource and I have a great appreciation for all those who have invested their time into making this kind of information available to schmuks like me.

[tubetek]

Howdy Tom-
How old is your VARIAC? Did you buy it new?
Reason I ask, I had similar problems a few years ago with a
unit I purchased from AES. They recalled the entire shipment and refunded everyone's money! I then purchased one for $2.00 at a yard sale; It was an open-frame model that some old TV tech cobbled into a project box; Not
pretty but safe and stable. Good luck sorting this out...My guess is you should
be looking for a replacement (no warranty?)
tubetek

[ampdan]

Tom, I've got to agree with tubetek time for a new variac.

[ApexJr.]

I suspect you have one of the china ones that people
have been buying.... Get rid of it.... It's red ?
Get an American one --- Superior Electric, Staco, or General Radio

Superior Electric is the better one..

I have some in stock if you email me with the amperage you need
I can tell you what I have in stock and the prices..

Or you can look on ebay too...

Steve @ Apex Jr.

[tomrasdf]

Bummer. Well, lesson learned I suppose. I'm lucky enough to still be in college so I'll talk to my physics prof and see if I can borrow one from the electronics lab for a bit, but I might be in contact with you soon, Apex. Yes, it is painted red... What's the racket? I've heard that some sellers are "refurbishing" old variacs with a new paint job and sending them off, but I made sure this one was new, or so I thought. Are some brands just shoddy?

-TR

[ApexJr.]

Yes...
The ones from Asia are not made well and don't last long.
Don't get me wrong they do work but are NOT built like
the ones here in the US.
I have friend who buys up variacs and rebuilds them and
then resells them. They are american and are up to manufacturer
spec's. Mine haven't been rebuilt but are american and all
the name brands and are also guarenteed.
Even if you don't buy from me look for these brands in this order.
Superior Electric, Staco and General Radio there are others
Ohmite, Adjust-A-Volt to name a few, but the bottom line
buy an american variac it will last forever...

Steve @ Apex Jr.