Simplistic Mosfet HV Shunt Regs

[Salas]

And see how it tames with the Zobel. Now you understand why I wrote that you must not put random filters at its output in a previous question of yours.

[JC951t]

Thank you both

[JC951t]

Hi Salas,
Sorry another question. If the Reg is built outboard,
should a cap be needed on the main board ?

Thank you again.

[Salas]

Put a good film cap on board with the circuit, say 10uF, very near to its consumption point after all cable. That will act as a local bypass. The reservoir capacitors before the PSU are the storage, and this energy passes through.

[chatziva]

Originally posted by salas


P.S. Is this the preamp you are talking about? If yes, the PSU examples that you see here are overkill for current, dissipation - heat sinking. So, I instruct you a tailor made power scaled schematic if I may. You can see it attached. A 230V 100mA transformer and 4X UF4007 arranged as a bridge rectifier feeding a 220uF/350V capacitor is all you need for Vin. Also 2X rudimentary 3W heat sinks like those they mount LM317T regulators on.

Euxaristw para poly for the advice Salas!!

[chatziva]

Originally posted by salas

So, I instruct you a tailor made power scaled schematic if I may. You can see it attached. A 230V 100mA transformer and 4X UF4007 arranged as...

Salas I am confusing myself. When you say I will need a 230V transformer, do you mean with 230V secondaries?

According to the personalised schematic you prepared for me don't I need a trafo with 320V output ???

Here in the UK we have 230V mains, therefore I will need a trafo with 230V input, 320V output right??

From a quick look in farnell I can't find any suitable trafo. Did you wind your own trafo ?

[Salas]

230V primary and 230V secondary, happens you need 1:1 ratio in this case.

Parakalw (you are welcome).

[chatziva]

Originally posted by salas
230V primary and 230V secondary, happens you need 1:1 ratio in this case.

Parakalw (you are welcome).

I see.

I was confused because you specified 320V (in red circle) in the schematic attached, so I thought a trafo with 320V out was needed.

Kalo brady

[Salas]

320V indeed but rectified DC, not AC. Its a regulator, needs DC. You will get over 300V DC when you rectify your 230V AC secondary.

Goodnight to you too, be careful with the high voltages, keep one hand in your back pocket when testing your new 12AX7 preamp and shunt PSU.

[chatziva]

thanks for the advice, much appreciated

I have one more question, last one hopefully

I can't find BC560B's here in the uk, only BC560A or BC560C

the difference is in the hFE value

A is 110-220, B is 200-450 and C is 420-800

does it make any difference if I go for the BC560C ?