Regulated Power Supply For F3 (zen V9)

[gionag]

Hi folks,

I'm trying to do a better Power Supply for Zen v9 and my idea was to implement the regulated power supply based on the Nelson Pass Document where he explain how to use a regulated power supply applied to a Zen V.3 HERE THE PDF.

NOW, from the beginning i'm intended to use a 650VAC toroidal-transformer custom made by "italsistemi" for audio purpose

The SPECS are :
225 Volt PRIMARY (this is the voltage in my house)
2x41 Volt SECONDARYs (1 RAIL FOR CHANNEL) (I want to supply Zen with 50VOLT)

After the bridge i'd want to use ONLY 40.000uf of filtering (each channel).

Here the base schematics of regulator

An externally hosted image should be here but it was not working when we last tested it.

After the filter I theorically have : 41 * 1.414 = 58Volt (arrot).
From this 58 Volt i subtract the 4 Volt of the IRFP240 (that actually make the regulation (Q1)) and remain another 4 voltage that i drop on the R1 making the right current (2mA) for the Zener Stack.

Then the value of R1 is : 4 Volt / 0.002 A = 2000Ohm and the power is P = (V * V) / R = (4*4) / 2000 = 16 / 2000 = 0.008Watt.

As i say before the Q1 is an IRFP240 and i supply that with a stack made by five 10Volt 1/2W Zener.

C1 and C2 are 220uf 63 Volt and R2 is 1500ohm.

Do you think that is right ?
Tell my if I am wrong. I'm not an engineer and i'm trying to make light in my head about this questions.

THANKS TO ALL !
You're a great support.

Michele

 

[h_a]

Hi Michele,

I just want to hint you that the F3/Zen#9 already uses a capacitance multiplier which is a sort of regulated psu.

However if you want to do it, do it

The real gain is adjusting the source degeneration resistors for nice loadline cancelation as described in the article.

Have fun, Hannes

 

[gionag]

Hi Michele,

I just want to hint you that the F3/Zen#9 already uses a
capacitance multiplier which is a sort of regulated psu.

However if you want to do it, do it

The real gain is adjusting the source degeneration resistors for nice loadline cancelation as described in the article.

Have fun, Hannes

What is the capacitance multiplier ? and how it works ??

thanks a lot

 

[Nelson Pass]

The ZV9 already has the circuit you are likely to want - just put
some Zener diodes in parallel with the capacitor that drives the
Mosfet.

 

[gionag]

The ZV9 already has the circuit you are likely to want - just put
some Zener diodes in parallel with the capacitor that drives the
Mosfet.

What is exactly the "capacitor that drives the mosfet" ? maybe is the 220uf 63volt cap ? os you intend the main filtering cap ?

 

[gionag]

Anyway, there's problem using a regulated power supply ?

thanks !

 

[Nelson Pass]

What is exactly the "capacitor that drives the mosfet" ? maybe is the 220uf 63volt cap ? os you intend the main filtering cap ?

When you look at the circuit you posted at the beginning of this thread,
you should notice that the Zen 9 has the same circuit, minus the zener
diodes. If you want to add the zener diodes, the circuit will then be regulated.

I personally don't bother as the Zen 9 is largely self regulating anyway by
virtue of the current source and the negative feedback. The filter system
provides slow turn-on and low noise.

 

[gionag]

thanks... then i'll try with the zener diode, i'll put a 50 Volt 1 Watt zener across the 220cap (C3), Then the ouput voltage at source of Q4 should be 46 Volt but with an ..."Old-School"... Voltage stabilization. that's right ?

Thanks for support.
Michele