Aleph2 PSU questions

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Hi,

What is the voltage drop on the PSU when it is loaded with the rest of the circutry. To get the rails to 45 VDC unloaded you need to use a 33V [(Vrms+1.4)*sqrt2] transformer. But is it enough? I am thinking about getting a pair of 500VA torroids from Piltron and they do have 33V secondaries. Would increasing the PSU capacitance decrease the voltage drop?

dee
;-D
 
Dee,
I'd recommend going for 750 VA, minimum (I've got 1000VA Plitrons on my Aleph 2s, filched from an unfinished project--still need to order proper transformers for the Alephs). 500 VA would be cutting it a bit thin. The 45V rail isn't unloaded--it's going to have to deliver 3A or so at that voltage, and that's at idle. If you pull back too much, the rail will drop, and the transformer will tend to run hot.

Grey
 
PSU

Thanks Grey,

I was just doing some calculating before jumpin' in both feet. Is 33Vs enough or jum to 35V? Going to the 1.5KVA puts you in the 38V minimum output which vould yield a 55VDC unloaded output. How much would the load pull that down? 10%?

dee
;-D
 
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