BOSOZ PSU question

Tyimo · 29th January 2005, 10:55 AM

Hi!
I would like to build the BOSOZ's PSU with lower regulated voltage, ca. 40 V.

I know that: ".... It is possible to set up the power supply to regulate at lower voltages. Alternately, you might choose a single transformer that does not develop as much voltage as two D4007's. Simply replace some ofthe Zener diodes with shorting wires to produce lesser referencevoltages in increments of 9.1 Volts, or replace the 9.1 volt parts withother values....."

My question is:
-what kind of transformer is ideal for the the desired regulated 40V, if I would use 7x5.6 zenners?

Thanks

Tyimo

jh6you · 30th January 2005, 04:15 PM

Nelson Pass prefers the toroidal transformer.
I use a toroidal transformer for my BOSOZ, but will not hesitate to use EI type if available.

eLarson · 30th January 2005, 09:39 PM

When using lower voltage rails, you could probably scale back some of the resistor sizes from the original article, giving you higher bias current and a little higher drain voltage than with the original resistors.

Tyimo · 31st January 2005, 04:49 PM

Hi!
Thanks the answers, but I mean/ask, how many secondary voltage of the toroid need for the desired regulated 40 V?

Tyimo

Tyimo · 31st January 2005, 04:53 PM

sorry, one more thing:
I already built the BOSOZ and it is excellent! I would like to use the PSU board for an another preamp project!

Thanks!

Tyimo

eLarson · 31st January 2005, 06:28 PM

Sorry, Tyimo... I looked back at my post and it appears to be a bit of a non sequitur.

For ~40VDC rails you could probably get by with a transformer secondary in the 30 to 32V neighborhood, presuming that you're going to use a cap-input supply and not a choke-input raw supply.

Erik

Tyimo · 1st February 2005, 04:42 PM

Erik: Thanks.
I know the x1.41 rule, but I ask for the regulated PSU voltage?
I mean: in the original article: You use 60V secondary, get 80V unregulated DC and in the end you get 60V regulated DC.
So, should I use ca. 40V secondary to get the desired 40 regulated DC?
Greets:

Tyimo

BobEllis · 1st February 2005, 04:58 PM

Somewhere over 32 VAC would give you enough to drop ~5 volts in the regulator - about the minimum using FETs.

40 VAC will be work but watch the heat sinking of the regulator pass transistor. You'll need more than a clip on heat sink since you'll be dissipating more than 2 W if you run both channels from one regulator.

Tyimo · 1st February 2005, 05:11 PM

Thanks Bob!
Now I see.

Greets:

Tyimo

Tyimo · 1st February 2005, 05:14 PM

Oh, and do you mean it with 7x5.6 zenners?

29th January 2005, 10:55 AM	#1
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	BOSOZ PSU question Hi! I would like to build the BOSOZ's PSU with lower regulated voltage, ca. 40 V. I know that: ".... It is possible to set up the power supply to regulate at lower voltages. Alternately, you might choose a single transformer that does not develop as much voltage as two D4007's. Simply replace some ofthe Zener diodes with shorting wires to produce lesser referencevoltages in increments of 9.1 Volts, or replace the 9.1 volt parts withother values....." My question is: -what kind of transformer is ideal for the the desired regulated 40V, if I would use 7x5.6 zenners? Thanks Tyimo

30th January 2005, 09:39 PM	#3
eLarson diyAudio Member Join Date: Aug 2002 Location: Gaithersburg, MD	When using lower voltage rails, you could probably scale back some of the resistor sizes from the original article, giving you higher bias current and a little higher drain voltage than with the original resistors. __________________ Would a woodchuck bother to chuck MDF?

31st January 2005, 06:28 PM	#6
eLarson diyAudio Member Join Date: Aug 2002 Location: Gaithersburg, MD	Sorry, Tyimo... I looked back at my post and it appears to be a bit of a non sequitur. For ~40VDC rails you could probably get by with a transformer secondary in the 30 to 32V neighborhood, presuming that you're going to use a cap-input supply and not a choke-input raw supply. Erik __________________ Would a woodchuck bother to chuck MDF?

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30th January 2005, 04:15 PM	#2
jh6you Account Disabled Join Date: Aug 2002 Location: Near to the Pacific Ocean	Nelson Pass prefers the toroidal transformer. I use a toroidal transformer for my BOSOZ, but will not hesitate to use EI type if available.

31st January 2005, 04:49 PM	#4
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	Hi! Thanks the answers, but I mean/ask, how many secondary voltage of the toroid need for the desired regulated 40 V? Tyimo

31st January 2005, 04:53 PM	#5
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	sorry, one more thing: I already built the BOSOZ and it is excellent! I would like to use the PSU board for an another preamp project! Thanks! Tyimo

1st February 2005, 04:42 PM	#7
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	Erik: Thanks. I know the x1.41 rule, but I ask for the regulated PSU voltage? I mean: in the original article: You use 60V secondary, get 80V unregulated DC and in the end you get 60V regulated DC. So, should I use ca. 40V secondary to get the desired 40 regulated DC? Greets: Tyimo

1st February 2005, 04:58 PM	#8
BobEllis diyAudio Member Join Date: Sep 2003 Location: Upstate NY	Somewhere over 32 VAC would give you enough to drop ~5 volts in the regulator - about the minimum using FETs. 40 VAC will be work but watch the heat sinking of the regulator pass transistor. You'll need more than a clip on heat sink since you'll be dissipating more than 2 W if you run both channels from one regulator.

1st February 2005, 05:11 PM	#9
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	Thanks Bob! Now I see. Greets: Tyimo

1st February 2005, 05:14 PM	#10
Tyimo diyAudio Member Join Date: Nov 2002 Location: Hungary	Oh, and do you mean it with 7x5.6 zenners?

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