adyhansolo

I appreciate you waste your time with my problem. I measured with two multimeters, including a new one, with the same result. Why the measurements it's correctly in the second circuit ( without negative voltage)?

I measured the voltage with a portable digital multimeter (a good one). Any idea?

It's very strange for me. Maybe if you see this photos with the measurements you can give me the solution. The second is with the circuit interrupt (rectifier bridge- R2). [img width=680 height=341]

Hi Audioguru, I don't find the solution of my problem. I checked all the components again and the voltage still remain 54Vdc( measured at C1 pins). If I disconnect R2 the voltage found is normal, 39Vdc. What is wrong? Please help me.

Thank you Audioguru for your replay. I know the peak voltage should be around 42 Vdc, but I don't understand what is wrong. The filter capacitor is ok, it's discharged by R1. Could be the bridge rectifier defective ? I measured the negative voltage ,too. It was 1.47 Vdc. It's ok or it's too high?

Hi, I need your help. I built this project (last version with MC34071). I tried to run the power supply in this morning. I measured the input voltage before insert the op amps in the sockets. The AC voltage was 30V, but the DC voltage was more than 50V, about 55Vdc. I used two caps 6800uF/63V in parallel. I changed them with one 15000uF, but no modification. I measured with , two different digital multimeters with the same value. What is wrong? Please help and excuse my english.

Hi, Can I use for the 3 single opamp only one quad opamp MC34074 ?