This might be a bit of overkill, but you might look into one that is super adjustable like this. I've never used one this configurable, but it appears you can use the potentiometer to set the V anywhere from 3 to 24, so you'd be able to get your 5.7-5.9 spot. It has a variety of modular tips so you can check if it includes the one you need, and importantly it has a polarity switcher so you can be sure it can be configured to the polarity setting you need.
Hopefully this points you in the right direction, sorry if I'm missing something and it doesn't help.
Total guess but probably 12 volt , and at least 3 amp to be safe. For example this long string of LEDs is 12V 40 Watt, which is about 3.3 amps.
Then you have the cable top size to figure out.
You could get one of these adjustable supplies and probably find something that works.
But as everyone else has mentioned, check the back for details. You might even need to look up a part number for a LED controller or something like that. Good luck.
I was considering buying a subitism heater a few days ago, but I was encouraged by members (thanks u/mofaha) of the sub to build my own instead. It was way easier than I thought originally and thought I could share some info for those of you that want to do the same.
An older post by u/GlossyBean (thanks, BTW) ultimately helped me to make the decision to proceed with the DIY. He was kind to post the links to the parts, but some of them are broken already. So I thought that’s something I can contribute with. It would be redundant to list the step-by-step because they are well documented on the KyaraZen's guide page. It really digests it super easy for you.
I got the parts mostly from Amazon only because I wanted them right away. They weren’t as cheap as on Aliexpress, but I didn't want to wait 30 days or more. So, here is the list of parts:
1- Clear mica : <Etsy LINK>
2- Textured mica: <Amazon LINK>
(I decided to use this one for the lower layer of the burner to hide the circuitry and give it a cleaner look)
3- Nichrome wire: <Amazon LINK>
4- Variable-voltage Transformer: <Amazon LINK>
5- Female DC connector: <Amazon LINK>
6- M3 male-female brass spacers, screws and nuts kit: <Amazon LINK>
Note: I know most people use a small drill to make the holes in the mica. I used an awl instead to avoid mica dust flying around. You have to be gentle to avoid breaking the mica, but it worked great.