"Would It have to be a toroid or will a normal transformer do?"
There is no difference exept that the toroid is usually smaller than a normal El transformer.
Toroids also have a bigger inrush current. In a preamp you won't be using a 300VA transformer so it's not a problem.
For a preamp the transformers are small enough to give you with both options open.
There is no difference exept that the toroid is usually smaller than a normal El transformer.
Toroids also have a bigger inrush current. In a preamp you won't be using a 300VA transformer so it's not a problem.
For a preamp the transformers are small enough to give you with both options open.