I have done some searching on the forums but have not been able to figure this out. I have built linear power supplies using conventional center tapped transformers but have not used toroidal transformers with double secondaries before. I have built a Diyaudio PSU for my F5 using an Antek AS-4218 transformer which has 18 volt secondaries and it puts out 24 volts on each rail. I have ordered a Broskie power supply to use with a BA2018 preamp and I am trying to select the transformer. I will probably use a 50va as I believe this should be sufficient power for the application and was going to order an 18-0-18. Is there a formula that can be applied to calculating input/output for dual rail power supplies? Thanks for any input anyone can supply me.
What are the power supply requirements ?
There are several approaches to this.
Vdc = Vac x 1.4142 less the diode drops.
If you require 24Vdc then 18Vac is generally used.
Idc = Iac / 1.4142.
If you require 1Adc then 1.5Aac is generally used.
In HiFi it is often accepted that a 50% or more power margin is used so 18 x 1.5 = 30VA, most circuits would employ a 50VA transformer in this example.
There are several approaches to this.
Vdc = Vac x 1.4142 less the diode drops.
If you require 24Vdc then 18Vac is generally used.
Idc = Iac / 1.4142.
If you require 1Adc then 1.5Aac is generally used.
In HiFi it is often accepted that a 50% or more power margin is used so 18 x 1.5 = 30VA, most circuits would employ a 50VA transformer in this example.
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