I'm working on a project that combines a board from an electric organ with one of those cheap Chinese tube amps. The board requires +12V/-15V DC and the amp requires 12VAC.
I don't want to power the final product with two wall warts, because that would be fiddly and annoying.
The amp converts its 12VAC to ±30VAC internally, and my first thought was to power the amp off a 12VAC wall wart, then tap off the ±30 on the amp's board and power a 7812 and 7915 off of this (rectified first of course). But connecting them up causes a huge voltage drop, so it seems that this isn't going to work.
The current idea I'm working with is to power the whole project off a 24VAC wall wart, which will run the 7812/7915 combo fine, and also can step down at 2:1 to 12VAC for the amp.
My problem is that I can't find a 2:1 transformer suitable, but it seems impossible that such a thing doesn't exist. (The only 2:1 transformers I can find are huge, built to take 240V to 120V. This would work in principle but it would bring up the size/weight of the project by at least an order of magnitude which isn't ideal, to say the least.)
I bought some of these 78604-1C but they fry on 12VAC+ input. (The datasheet I have isn't forthcoming about a maximum voltage, which I am also confused about)
- Is there a specific thing I should be searching for that will turn my 24VAC to 12VAC in a small package?
- Or, is there some other way of solving this problem that explains why this type of transformer is so hard to find?