Help me improve this PSU. (6c33 set, voltage doubler)

rvrazvan · 13th July 2011, 07:34 PM

This is the base schematic.
The amplifiers will be monoblocks.
Chokes maybe?

I welcome any sugestion.

rvrazvan · 14th July 2011, 08:55 AM

up!

MrCurwen · 14th July 2011, 09:35 AM

Well, what is wrong with it? How do you want it to be better?

rvrazvan · 14th July 2011, 10:56 AM

I'm afraid of humming, and also i don't know how reliable the regulated part is.
I was also thinking about using chokes on the 210V rail.

MrCurwen · 14th July 2011, 11:58 AM

First off you need a capacitor, 22µF is fine, from heater offset to ground.

the_manta · 14th July 2011, 03:10 PM

Did you simulate the circuit with PSUD-II software ?

rvrazvan · 19th July 2011, 01:00 PM

Quote:

Originally Posted by MrCurwen

First off you need a capacitor, 22µF is fine, from heater offset to ground.

Could you tell me some details about this?

razorrick1293 · 19th July 2011, 01:42 PM

Quote:

Originally Posted by the_manta

Did you simulate the circuit with PSUD-II software ?

does PSUD-II simulate stabilized supplies?

Michael Koster · 03:02 PM

The stabilizer circuit doesn't look like it's set up for a very wide variation in line voltage. The zener string fed from a 2K7 resistor has a voltage tolerance of only +/- 10 or 20 volts.

Work out the power dissipated by the zener diodes for +/- 10% raw DC voltage variation out of the doubler. If the raw DC increases by 40 volts (+10%) then current through the zeners increases by well over 10 mA and they burn up. If the line voltage drops 10%, the circuit goes out of regulation (drop out) There will be some DC resistance internal to the zeners in series with the 2K7, but the better solution is IMO to replace the 2k7 resistor with a simple CCS made from a depletion FET and a couple of resistors, set at 5 mA current.

Your bias stabilizer needs a current limiter on the zener string as well. A resistor will probably work fine for this but a CCS here also will be stable, accurate, and quiet.

You can sim the 210 circuit with PSUD to get a feel for the ripple voltage and add chokes if needed. Separate chokes will also help isolate one channel's B+ noise from the other. The chokes would replace the 75R resistors and would probably be an overall improvement. PSUD is your friend.

Tony · 20th July 2011, 07:17 AM

i wouldn't do everything on one coil.....but this is just me.....

19th July 2011, 02:53 PM	#9
Michael Koster diyAudio Member Join Date: Jan 2008 Location: Bridgeville, CA	The stabilizer circuit doesn't look like it's set up for a very wide variation in line voltage. The zener string fed from a 2K7 resistor has a voltage tolerance of only +/- 10 or 20 volts. Work out the power dissipated by the zener diodes for +/- 10% raw DC voltage variation out of the doubler. If the raw DC increases by 40 volts (+10%) then current through the zeners increases by well over 10 mA and they burn up. If the line voltage drops 10%, the circuit goes out of regulation (drop out) There will be some DC resistance internal to the zeners in series with the 2K7, but the better solution is IMO to replace the 2k7 resistor with a simple CCS made from a depletion FET and a couple of resistors, set at 5 mA current. Your bias stabilizer needs a current limiter on the zener string as well. A resistor will probably work fine for this but a CCS here also will be stable, accurate, and quiet. You can sim the 210 circuit with PSUD to get a feel for the ripple voltage and add chokes if needed. Separate chokes will also help isolate one channel's B+ noise from the other. The chokes would replace the 75R resistors and would probably be an overall improvement. PSUD is your friend. Last edited by Michael Koster; 19th July 2011 at 03:02 PM.

20th July 2011, 07:17 AM	#10
Tony diyAudio Member Join Date: May 2003 Location: Palatiw, Pasig City	i wouldn't do everything on one coil.....but this is just me..... __________________ http://www.electronicslab.ph/forum/i...?topic=32688.0

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14th July 2011, 08:55 AM	#2
rvrazvan diyAudio Member Join Date: Jul 2010	up!

14th July 2011, 09:35 AM	#3
MrCurwen diyAudio Member Join Date: Feb 2010	Well, what is wrong with it? How do you want it to be better?

14th July 2011, 10:56 AM	#4
rvrazvan diyAudio Member Join Date: Jul 2010	I'm afraid of humming, and also i don't know how reliable the regulated part is. I was also thinking about using chokes on the 210V rail.

14th July 2011, 11:58 AM	#5
MrCurwen diyAudio Member Join Date: Feb 2010	First off you need a capacitor, 22µF is fine, from heater offset to ground.

14th July 2011, 03:10 PM	#6
the_manta diyAudio Member Join Date: Nov 2006 Location: Munich, Bavaria	Did you simulate the circuit with PSUD-II software ?

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