Hello, im using a transformer from an old Hi Fi and i want to build a new one, so this part is related to the power supply. Im a bit confused about the transformer since i cant find its datasheet there is nothing written on it, but i found the service manula from the hi fi and found how it was connected, if it helps. So my idea is to make +21 and -21 V, which i managed, i also want to use the 6 V and 8 V from the transformer, in order to get steady 9V DC from the 6V (with capacitors, voltage regulators etc) and get 12 V nad - 12 V (i dont know if its possible). So here is my circuit how i started it. Im confused how to make the bridge rectifiers after i did the 21V and - 21V, since the ground wont be the same? Thank you in advance