I'm looking to buy a toroidial transformer to maybe make a dual purpose power supply:

1. providing a clean high current (maybe 1.5 amps or so) +15V to power my Szekeres amp in one mode, or maybe a dual supply at +-15V for something else

2. power a virtual battery supply that'll keep NIMH batteries ~24V fully charged with a MAX712 circuit

How do I determine what specs of a toroidial transformer I should buy from a place like Digikey in order to supply enough voltage and current?

I noticed in Jan Meier's Corda power supply circuit he shows a toroidial transformer with 2 x 15V, 7VA. What does this mean? 2 15V secondaries and 7VA is the max voltage*current it has? Does that mean the current supplied if both secondaries are used is 7VA / 30V = 0.233 Amps?

If this is how it's calculated, that means I have to find a transformer that's 2 x 15V, 45 VA to get +-15V at 1.5 Amps?

Does the transformer have to have enough total secondaries voltage that can be combined to 30+ V so I can use maybe a LM317/LM337 combo to make the +- 15V, using a transformer that has maybe 20V and 12V secondaries? Or do I need something with at least 2 15V secondaries?

How do you determine the VA (VAC?) of a transformer if all a catalog gives you is a VCT of 88V, or secondaries of 44V as in this page:

http://www.allelectronics.com/cgi-bi...852&type=store

?

1. providing a clean high current (maybe 1.5 amps or so) +15V to power my Szekeres amp in one mode, or maybe a dual supply at +-15V for something else

2. power a virtual battery supply that'll keep NIMH batteries ~24V fully charged with a MAX712 circuit

How do I determine what specs of a toroidial transformer I should buy from a place like Digikey in order to supply enough voltage and current?

I noticed in Jan Meier's Corda power supply circuit he shows a toroidial transformer with 2 x 15V, 7VA. What does this mean? 2 15V secondaries and 7VA is the max voltage*current it has? Does that mean the current supplied if both secondaries are used is 7VA / 30V = 0.233 Amps?

If this is how it's calculated, that means I have to find a transformer that's 2 x 15V, 45 VA to get +-15V at 1.5 Amps?

Does the transformer have to have enough total secondaries voltage that can be combined to 30+ V so I can use maybe a LM317/LM337 combo to make the +- 15V, using a transformer that has maybe 20V and 12V secondaries? Or do I need something with at least 2 15V secondaries?

How do you determine the VA (VAC?) of a transformer if all a catalog gives you is a VCT of 88V, or secondaries of 44V as in this page:

http://www.allelectronics.com/cgi-bi...852&type=store

?