parallel CRC Filtering for B+

ackcheng · 2nd December 2005, 03:12 PM

Hi! I have come across with this topology for power supply filtering in a Class D design. It seems like a good idea.

http://www.lcaudio.com/index.php?page=45

I wonder if anyone tried this on tube amp and use this topology instead of the traditional CLC filter?

tubetvr · 2nd December 2005, 03:42 PM

Quote:

It seems like a good idea.

What is good about it? a resistance that low doesn't do much for filtering.

Quote:

I wonder if anyone tried this on tube amp and use this topology instead of the traditional CLC filter?

I think you will find that a CLC supply is superiour to any CRC supply as a choke acts as a high impedance for AC but very low for DC which give a much more efficient filtering.

Regards Hans

anatech · 2nd December 2005, 11:26 PM

I'll agree with Hans,
The supply in the link would need to have it's values adjusted a lot. It's still not a good idea. C-L-C supplies are best used when there is a minimum load current over the critaical value for the inductors, or the ripple voltage goes up and the filtering action of the choke is lost.

An electronic regulator before the voltage amp section would enhance the performance of an amplifier.

-Chris

Miles Prower · 4th December 2005, 04:53 AM

Quote:

Originally posted by ackcheng
Hi! I have come across with this topology for power supply filtering in a Class D design. It seems like a good idea.

http://www.lcaudio.com/index.php?page=45

I wonder if anyone tried this on tube amp and use this topology instead of the traditional CLC filter?

It is a good idea for a solid state amp. The big difference is that this is a low voltage, high current PS. VT's are high voltage, low current devices, and so, you'd be better off with the usual CLC filter. The "LC" + load resistance part of the CLC forms a second order LPF that gives -12db/octave of roll off. The RC filter is a first order LPF with just -6.0db/octave of roll off. That's twice the ripple attenuation with the LC design.

This just won't translate to the high voltage, low current situation. Best keep it for your mega-power SS designs.

ackcheng · 4th December 2005, 07:04 AM

Thanks Miles,

For your detailed explanation!

2nd December 2005, 03:12 PM	#1
ackcheng diyAudio Member Join Date: Dec 2003 Location: hong Kong	parallel CRC Filtering for B+ Hi! I have come across with this topology for power supply filtering in a Class D design. It seems like a good idea. http://www.lcaudio.com/index.php?page=45 I wonder if anyone tried this on tube amp and use this topology instead of the traditional CLC filter?

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2nd December 2005, 11:26 PM	#3
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	I'll agree with Hans, The supply in the link would need to have it's values adjusted a lot. It's still not a good idea. C-L-C supplies are best used when there is a minimum load current over the critaical value for the inductors, or the ripple voltage goes up and the filtering action of the choke is lost. An electronic regulator before the voltage amp section would enhance the performance of an amplifier. -Chris

4th December 2005, 07:04 AM	#5
ackcheng diyAudio Member Join Date: Dec 2003 Location: hong Kong	Thanks Miles, For your detailed explanation!

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