placetime, you are right on. Most all log vapes use the same 5.5 x 2.1 mm female pug. That plug looks like it should be called a 'male' but it is a female because when you plug it in to the log vape or any device, it gets penetrated with a small round rod. Enough.
It is also correct that the plug used to plug into a Tattoo machine VVPS is a 1/4" standard mono audio plug. You do want a mono plug as the stereo plug has extra connections not needed for use in a VVPS.
I also want to mention again that if one has the Tekpower VVPS, you do not need banana plugs at the power supply end of the power cord. The red and black power plugs on the tekpower will actually uncrew(top portion) so you can wrap a stripped end of a wire around the post, then screw the top part back on, making a great connection.
That is the way I use my Tekpower VVPS and always have. It was the first VVPS I ever bought and the one I am using now. For some reason, LEO left my Tekpower PS in my shop. I guess they were too busy grabbing up all my cull Zap shells, screens, clips, heaters, etc to notice the red flamed Tekpower. I surely am thankful for that as they took every other power supply, fixed or variable, from our home on 7/25.
BTW, just in case old Zap customers(or anyone) do not know, I strongly recommend the UD for anyone looking for a good log vape. I have had several old customers ask lately. Many go several years back and have never seen FC. One of them said "I have had a Zap on my desk for ten years"................
I see the new Tekpower is not red with flames but now white in color. Same machine though with the same output plugs that will unscrew for a bare wire install. Polarity does not matter with a log vape unless it has an "on" led light. Then center pin positive for light to work. A very good VVPS BTW for $40.