@gajan
i have only used the stock values fr7 diodes for rectification and 1% resistors except c17 and c18, they are 100mfd 25v. the voltage at the output is 14.52 volts with sometimes changes in the most significant left hand digit i.e 14.5'2'-14.5'3' i have no clue to check if the output is regulated as i dont have a scope with me. the calculations are right, the regulator SHOULD PUT OUT 15.1 VOLTS BUT I DONT KNOW WHY IS IT SHOWING ONLY +-14.5.
@Andrew i have found a little transformer 18-0-18 in a very small EI cored package, the bobbin size is 2x4 centimeters. i am unsure about the current of the transformer but i am sure it can atleast put out 250mA of current so it is perfectly suited for this application.
Update- this transformer puts out 18 volts at 500mA.which is more than sufficient for all the 5532 dual op amps(only 3 though 2 for project 88 and 1 for subwoofer filter)
i have only used the stock values fr7 diodes for rectification and 1% resistors except c17 and c18, they are 100mfd 25v. the voltage at the output is 14.52 volts with sometimes changes in the most significant left hand digit i.e 14.5'2'-14.5'3' i have no clue to check if the output is regulated as i dont have a scope with me. the calculations are right, the regulator SHOULD PUT OUT 15.1 VOLTS BUT I DONT KNOW WHY IS IT SHOWING ONLY +-14.5.
@Andrew i have found a little transformer 18-0-18 in a very small EI cored package, the bobbin size is 2x4 centimeters. i am unsure about the current of the transformer but i am sure it can atleast put out 250mA of current so it is perfectly suited for this application.
Update- this transformer puts out 18 volts at 500mA.which is more than sufficient for all the 5532 dual op amps(only 3 though 2 for project 88 and 1 for subwoofer filter)
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250mAac from a 18-0-18Vac transformer requires it to be 9VA.
250mAdc from a 18-0-18Vac transformer requires it to be 18VA.
Neither of these is small.
I suspect your MAXIMUM continuous DC output <<100mAdc.
If it is 3VA then it's AC rating is 83.3mAac. It's DC rating is 42mAdc and I would recommend that you do not try to draw any more than 20mAdc continuous from a 3VA.
How can you be "sure" of >=250mAdc?
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I had used a multimeter to measure the AC current through the transformer secondaries, it showed me .52 amperes of current.i am not sure if the way of measuring the current is right or wrong.i did it only for a short period.
@ gajanan, the value mentioned in the first post is 1.33k and i have used two resistors 1k and 330ohms in series to give 1.33k from ground to adj pin. this value is suited for +-15v i feel the suppy is completely regulated, because no matter what i feed it, 13-0-13Vac, 18-0-18Vac or even 25-0-25Vac the voltage is the same... 14.5
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