#26 pre amp

[merlin el mago]

Originally Posted by Wavebourn

Try to add resistances and inductances of wires into your SIM, variable current drawn, and you will see why ground sign have to be drawn near C3 instead of near C1.

I always read all people said to connect the ground to 1st cap psu

[merlin el mago]

Originally Posted by mogliaa

Felipe, that's not my design. Either way 12mvpp ripple is not bad at all! Are you planning to use a shunt regulator?
Ale

I'm sorry Ale the post was for Andy. Yes, Salas hig voltage shunt regulator version 2
Felipe

[merlin el mago]

Originally Posted by euro21

Felipe, can I do some comments?

Such a low transformer DCR not optimal for (mesh) AZ1. It would be better 100-200R DCR.
IMHO C1 low, thus output voltage also low. There are no high charging current (AZ1 unable to do so) therefore increase C1 up to 1-5uF. If output ripple bothering you, increase C3.

ps. PSUD a little cheating, output voltage about 220V, not 230.

Ps2. Attachment is my working #26 preamp (common raw PSU- each side: SSHV2- cascode CCS loaded 26 -TVC) raw HT supply.

Of course you are welcome, you are right because one time for other project I use AZ1 with other transformer with secondary DCR 83,2 ohms and was to add one resistor in series with the phase of 78 ohms or AZ1 not optimal.

Thanks for support and advices

[palmas]

Originally Posted by merlin el mago

Ale I have simulated your PSU, simulator saids have more ripple, or I'm misunderstanding something, see attached image.

In simulation you have 10H 10Ohm chokes for 30mA
More realistic would be 100 to 300Ohm choke. That can make some difference on the outcome

[merlin el mago]

In place to use two 125VAC in series what about to use as an isolation transformer to get 230VAC, due to the fact that I don't need so hign voltage can get a better psu?

[merlin el mago]

Originally Posted by palmas

In simulation you have 10H 10Ohm chokes for 30mA
More realistic would be 100 to 300Ohm choke. That can make some difference on the outcome

Thanks for advice, could I add in series resistor 290R? could you elaborate so I can learn? psud2 don't show any difference of ripple.

[palmas]

Originally Posted by merlin el mago

Thanks for advice, could you elaborate so I can learn.

10H chokes have thousands of spirasl in a iron (typically) core, so you cannot use big seccion wire, or it won't fit, or it will be enourmous and very expensive.
So you use thin wire (as requested by the 30mA), so wire resistance will be a lot higher than 10Ohm. Fro experience (I build them myself) for a 10H 200mA choke resistance will be about 100Ohm and for a 10H 100mA typically about 300Ohm. For 30mA could be more.
If you make that change on the simulator you will see that output voltage and ripple are a little different.

By the way, 0,1Ohm on caps is also too low if you're using electrolitic.

Cheers

[palmas]

did you measure inductance with 100mA?

[merlin el mago]

Originally Posted by palmas

10H chokes have thousands of spirasl in a iron (typically) core, so you cannot use big seccion wire, or it won't fit, or it will be enourmous and very expensive.
So you use thin wire (as requested by the 30mA), so wire resistance will be a lot higher than 10Ohm. Fro experience (I build them myself) for a 10H 200mA choke resistance will be about 100Ohm and for a 10H 100mA typically about 300Ohm. For 30mA could be more.
If you make that change on the simulator you will see that output voltage and ripple are a little different.

By the way, 0,1Ohm on caps is also too low if you're using electrolitic.

Cheers

Thanks for advices, I use Bartolucci chokes are rated 10H 100mA 10 ohms, attached pic.

I'm using mkp in oil ASC X386S, attached pic.

Cheers
Felipe

P.S. How can measure lytics impedance?

[palmas]

I need to buy these bartolucci chokes and reverse engineer them!

About the caps it is easier to rely on manufacturer specs and calculate connections resistance. But there is not a significant difference from 0.1 to 1Ohm on the cap