I did several searches and was surprised I couldn't find the answer to this, it's pretty basic. The closest I could find was this thread
I'd like to build a basic bi-polar power supply for something similar to a CMoy or Grado RA1 circuit. It's a very simply amp, so I'd rather not spend much money on it. I've attached the circuit I'd like to breadboard, just substitute 115V for the transformer primary.
Regarding transformer selection, I've seen +/- 15V in the wild, but few and far between. Is it acceptable to use a 30V CT, with the center tap at 0V? I was looking at this Hammond unit 166G30: 166G30 Hammond Manufacturing | Mouser
...or this flat pack style transformer:
LP-30-400 Bel Signal Transformer | Mouser
Any input would be much appreciated. Thank you.
I'd like to build a basic bi-polar power supply for something similar to a CMoy or Grado RA1 circuit. It's a very simply amp, so I'd rather not spend much money on it. I've attached the circuit I'd like to breadboard, just substitute 115V for the transformer primary.
Regarding transformer selection, I've seen +/- 15V in the wild, but few and far between. Is it acceptable to use a 30V CT, with the center tap at 0V? I was looking at this Hammond unit 166G30: 166G30 Hammond Manufacturing | Mouser
...or this flat pack style transformer:
LP-30-400 Bel Signal Transformer | Mouser
Any input would be much appreciated. Thank you.
Attachments
Yes, a 30 volt centre tap type can be used just the same as transformer with two separate 0-15 windings.
Remember it is all AC and so -/+15 doesn't apply to the transformer. It would be a 15-0-15 for a centre tap type and 0-15 and 0-15 for dual secondaries... which you would series connect.
The Bel is such a dual secondary type. Look at the data sheet and you will see how to connect it. Pin 6 and 7 join together and become the centre tap with 15 volts AC available either side on 5 and 8. There is no polarity, 5 and 8 can be interchanged when you connect it to your circuit.
Edit... and the primaries will connect in parallel for 115 vac and series for 230vac. It is vitally important to match the phase dots on the primary.
So 1 and 3 join together and 2 and 4 join together for 115vac operation.
For 230 vac they are in series similar to the secondaries. Here 2 and 3 would join and 230vac applied to 1 and 4.
Remember it is all AC and so -/+15 doesn't apply to the transformer. It would be a 15-0-15 for a centre tap type and 0-15 and 0-15 for dual secondaries... which you would series connect.
The Bel is such a dual secondary type. Look at the data sheet and you will see how to connect it. Pin 6 and 7 join together and become the centre tap with 15 volts AC available either side on 5 and 8. There is no polarity, 5 and 8 can be interchanged when you connect it to your circuit.
Edit... and the primaries will connect in parallel for 115 vac and series for 230vac. It is vitally important to match the phase dots on the primary.
So 1 and 3 join together and 2 and 4 join together for 115vac operation.
For 230 vac they are in series similar to the secondaries. Here 2 and 3 would join and 230vac applied to 1 and 4.
Attachments
