2 variac's video link

[jnew]

Hope this helps.

https://www.youtube.com/watch?v=jzLbqP4pvbs

[mightymike]

I have 3 variacs and all of them are 3 prong. I took a 3 prong extention cord to make my pigtails. This way, no matter which variac I use, my orientation will be correct.

Here's a few things, if you go the 3 prong method.

1) Don't just trust the colors. Turned out the manufacturer put my speaker cable wires backwards.

No biggie just remember..

2)If you look at the recepticle on your wall. Top left slot is where the bigger prong/nuetral/white which goes /to sleeve on the 1/4in guitar plug. Black wire goes to top right prong/which follows through to tip on the 1/4in guitar plug on the other side.

3) When you are done making your 2 pigtails, plug them together so it looks like a weird ass guitar cord. Then with your multimeter set to ohms, check sleeve to sleeve, and tip to tip for continuity just like you would check a guitar cord.

You can even pull them apart and check the male 3 prong top left to sleeve, and top right to tip as well.

[efraser68]

Great visual illustration, thanks James

[jnew]

[jape88]

Nice vid James.

Is it possible the more you dial down on the variac (between the cab) that the resistance would build up heat? and potentially cause stress on the transformer?

[jnew]

Not sure if you mean the amp Opt Trans, or the Variac transformer but in either case, neither ever get hot to the touch. Actually not even close. But in all fairness, I've never run the 2nd variac outside the range of 70 to 90 on the knob. Just don't feel the need to push things just to see if there will be any negative implications, when the tone that works for me is right there. You'll see what I mean if you get around to trying it.

[erupturchops]

Jnew,

Thanks for the video. I noticed on your comments you said you were able to test the impedance for the variac. Mind explaining how you did that? Appreciate the help.

[jnew]

Yep. Depending on the variac, you can either measure the + and - post's on the input, or if it's a variac with an AC cord, you just measure the across two blades on the AC plug. (Remember, no ground is used). This would be the primary side. On the secondary side, it's the same. Output binding post's or blades of the AC socket. The output side Ohms reading should swing as you mess with the dial on the variac while the primary side stays consistent. At least mine seems to.