ono and zener regulated power supply

[patriz]

hallo, as my ono phonostage is working wonderfully I'm trying to adopt the same zener regulated power supply for another project.
I need +/-24V and I'm using a24x2 transformer. I changed the zener to 6,8V and without load I have 23,9V at the output but loaded it drops to 21,9V and Vgs is only 4,6V, which is low for the current I'want.
I don't have the knowledge to solve by myself I appreciate your suggestion.
gio

 

[Alain Dupont]

patriz,

Here is the ONO power supply, which of the zener did you replace and what transfo did you use for your a 24x2 transformer VA ?

Regards.

Alain.

 

[patriz]

I replaced D1-D9 with 6,8V zeners.
the trans are r-core and actually are 23X2V.
Giorgio

 

[Alain Dupont]

patriz,

The 2* 24 AC transfo should do the job, it will give you 2*32 DC volts
and after the MosFets +-27 volts

The question is how much current you need now compared to the ONO

The resulting voltage should be stable, you have 10 volts more than the final DC output for the output,

But if the transfo is only 23X2 AC after the bridge its 23*1.33 = 30.5volts
the final could deliver about -+ 22 volts max...

You have to consider the 5.1 Ohms loss also, it is included in the CRC just after the bridge, I would like to know the DC "curent" you need to adjust all to work perfectly...

I"ll could check in PSU Designer, but I need to know the DC current !!!

Regards.

Alain.

 

[patriz]

alain,
after the bridge I have 28,8-29,1V
the load appear to need 200mA.
In those condiction I have 22,1-22,5V on the output. But if I put another 5,1R (R43)and 1000mf (C21) on the ouput the ripple seem to be pretty lower . This will lower the output voltage to 21,1-21,5V
Giorgio

 

[Alain Dupont]

patriz,

before putting a CRC on the output, better try putting 2 larger caps
after the bridge, say 2*5.000 or 2*10.000 microF
and perhaps lower a little the 2* 5.1 Ohms to 2*3 Ohms

My PSU designer is uninstalled, but if you have a PC
try to find "PSU designer" its a modeling soft for power supply's
and a good one.

Best regards.

Alain.