Paradise Builders

[analog_sa]

Originally Posted by sq225917

It would be really nice if anyone else from the large group buy could say they had built the psu section on theirs and it worked.

Yup, works fine. Check again, post pics of that section.

[sq225917]

Found it, not using a dual rail psu, corrected psu output to ground and sorted it.

[RCruz]

Originally Posted by sq225917

Found it, not using a dual rail psu, corrected psu output to ground and sorted it.

Please explain... You did not use a dual rail psu ?

[Joachim Gerhard]

Very good.

[brozatus]

Hello,

I think I need some help from you.

I built up the preregulator according to Joachims schematic:
Paradise Phono Preregulator

I have a 240 V 2x24 V transformer which measures 27,6 V ac each secondary.
The chokes are in place.
Now I have 37,3 V dc between plus vdc and ground, and -37,3 V dc between
minus vdc and ground, 74,6 V dc between plus vdc and minus vdc.
I also have plus/minus 81,5 V AC between plus/minus vdc and ground and
163 V AC between plus vdc and minus vdc.

I am not sure this will be right and have fear to power up the paradise with this unit.

Thanks a lot,
Christoph

[Joachim Gerhard]

Could you make a little drawing on paper with the circuit you build, scan it in and post it.
163V AC between plus/minus is a lot. Do you measure with a very high impedance DMM ?
What you could try is ballast the pre regulator with dummy resistors.
Say you want to draw ca. 50mA. Then you have 37,3 V / 0,05A = ca. 750 Ohm.
This resistors have to withstand at least 2W. The DC voltage will drop a bit.
Please remeasure AC voltage after you have put the resistors in place.

[brozatus]

Hello Joachim,

thanks for your reply.

It is just the schematic you posted and I have linked.

My dmm is a simple Peaktech 1075 PEAKTECH 1075 - Digital-Multimeter 3 -stellig, Spannungsdetektor bei reichelt elektronik

I have to buy the resistors you recommend, have no spares in this value.

The transformer is connected with both secondaries to the inputs.

Regards,
Christoph

[Joachim Gerhard]

I checked my schematic and when you have build it that way it should work fine.
It could be that there is some inductive coupling between the coils when you have put them too close together.
You can make your own high wattage resistor by paralleling some. Say you use 5kOhm 1/4 W resistors. You can parallel 10 to get 500 Ohm. That value is alright too.

[brozatus]

Hello Joachim,

I have built a nice necklace from 8 resistors and it adds up to 540 R and
put it in parallel to the outputs plus vdc and ground.

Now I measure between plus vdc and ground 29,7 V DC and 64,3 V AC.

Regards,
Christoph

[Joachim Gerhard]

I have a pre regulator that works and i will try to repeat your measurements.
I will look if there is any high AC voltage present. When it is present it does not violate the outcome. As i said my pre regulator works fine in praxis.