VEVOR500VA Auto Variable Voltage Transformer, 3.84 Amp, 110V Input 0-130V Output AC Voltage Regulator Power Supply, with 4 Extra Fuses Thermal Control Switch for Home Industrial Office

I ordered this because it was a better price than I thought it would be, so wasn't so sure the quality would be as good as the price, but wow was I wrong. This Transformer is incredible - Heave Duty and sturdy, and also heavy :). I also replaced the analogue meter with a digital one as the analogue meter was not very accurate, plus I wanted to be able to see a digital representation instead anyhow. It is a great addition to my bench and happy to be able to finally own one for my workshop.

Works great any time you need to regulate voltage. Works great as a fan/motor speed controller too. The built-in "gauge" markings on the top are off from the actual voltages, but are a decent approximation. The meter on the front is more accurate.

The transformer arrived on time and was well packaged. However.... due to the shipping company mishandling/dropping/bashing the package.... it was damaged upon delivery. There was a bashed-in dent on the side of the box which tore the cardboard and punched through the solid Styrofoam, snug fitting, packaging and into the side of the transformer. I contacted the seller the day of delivery with pictures of the damage. WITHOUT HESITATION!, the seller goes to make it right. The sellers response was prompt and professional. They offered, instead of incurring the high return shipping costs, to refund me all but 20 dollars of the purchase price and allow me to keep the damaged unit. I accepted this offer. I had to disassemble the transformer and pop out the dented housing which caused minor paint damage. The dent was so deep that the side of the housing contacted the toroidal coil inside and chipped/gouged into the insulating varnish on the copper windings. I just touched up the gouge and re-dipped the entire core in varnish after masking the bare track where the sweep brushes make contact. I also reflowed all the solder joints and applied insulating compound to each one. I added a 20 amp ceramic slow blow fuse and holder inside the front panel which protects the load/output since the unit only came with a standard fast blow 20 amp fuse on the input side of the transformer. This upgrade has already saved me multiple times! The digital voltage guage is accurate enough for most all of my needs. When I really need big power, I swap in say 50 amp fuses and this unit handles it fine for short runs! I've had this girl practically smoking with no harm done! Adding an external fan for forced air cooling is a big help when overdriving a variable. The biggest wear factor especially when over driving a unit like this is the brushes which are not only cheap and available, but easy to replace. The core itself is rather tough and can easily handle over its 20 amp rating for brief periods! Just ensure your brushes don't start glowing!! I'm VERY HAPPY WITH THIS PRODUCT AND THIS SELLER! I will buy from them again, as I already want at least 2 more of these little beauties! 5 stars.

It works exactly as it should but just do yourself a favor and ignore the gauge/wheel on top that shows the output voltage. This gauge is useless since it doesn't take into consideration the voltage from the source (your wall socket). If your original voltage ranges from lets say 114v to 123, the output will vary at the same wheel position. So just use the front display, it is close enough. I measured the accuracy of the front LCD display with a digital multi-meter and at times it was off a little, but it was OK. The meter was SLIGHTLY higher than the variac from about 0-70v. It was the same from about 70-110v, and the variac measured higher than the multi-meter from 110-140v. Since there are toe parallel receptacles, you can monitor the output with both the display and a separate meter, but they are close enough to where I don't think it will matter. I measured the voltage in my house at 121.6v at a location, then I dialed in 121.6v on my multimeter attached to the variac. The multimeter measured 121.6v while the variac measured 124. Some other voltage readings I took are: (Meter/Variac), 30/28, 50/48, 70/69. 80/80, 90/90, 100/100, 110/112, 120/122, 130/133. The highest readings I got were 143.8/147v. So, overall I'm happy with the accuracy, the build is heavy, all metal, with simple, cheap electronics inside, but for less than $100 you get what you pay for. Be gentle on the wheel up top, as the device is heavy and you will instinctually go to grab the up, but that's the weakest part. Grab/hold it from the bottom or side. Some might say this is cheap, and it probably is, compared to a Staco but this is a fraction of the price and it only needs to do ONE JOB, and it does that job. Just ignore the top wheel gauge. It's useless. It shouldn't even be there since there's a front LCD display. In fact, they should remove it, and use this 'savings' to add a metal handle to the top. If this broke, I would want to know why. If it were my fault, I would buy this again, but it craps out on me, I will look out for a used Staco with two jacks.

I needed this to test several audio power amplifiers that suddenly showed up on the bench. It worked as expected and exceeded expectations for performance. A good value for the money!

I bought this to use with vintage tube guitar amplifiers. Instead of surging power to the tubes I can bring the voltage up gradually to "warm" them up at home. If you are a gigging musician, you know your tube amp has an optimal operation voltage (noted on the backplate info). Power outlet voltage will vary enough for every venue and so will affect your "sweet spot". You can run your amp through this variac and adjust the output to your desired voltage and voila! Same voltage to your amp every gig. It seems to be built like a tank and has endured months of use.