CRC Filter ?

kacernator · 31st July 2009, 04:48 AM

Hi,

I have been experimenting with R value in CRC filter in my tube preamp. What I discovered that lower R values sound better to me than higher, although lower R has higher ripple.

Finally I settled on 220uF - 20 Ohm - 470uF. This filter hums a little, but I must put my ear right next to the speaker to hear it, so it is very quiet anyway.

With lower R in CRC the soundstage is much bigger, sound seems to be faster, better bass, better details, instruments are more separate from their self. Why is that? I thought that better ripple rejection the better sound?

diy4 · 31st July 2009, 10:09 AM

What was the original value of the resistor? Also, what were the DC voltages before, and after you changed the resistor?

AndrewT · 31st July 2009, 10:15 AM

what is the R of the transformer and wiring feeding the CRC?
You actually have an RCRC filter.
If you try adding a little extra R before the first C you may hear something else.
Even better, may be to replace part of the R with an air cored inductor (L+R). Adjust the fixed R values to give the desired (same) B+.

Do ensure that B+ is the same in all the implementations when making your sound quality assessments.

31st July 2009, 04:48 AM	#1
kacernator diyAudio Member Join Date: Jan 2008	CRC Filter ? Hi, I have been experimenting with R value in CRC filter in my tube preamp. What I discovered that lower R values sound better to me than higher, although lower R has higher ripple. Finally I settled on 220uF - 20 Ohm - 470uF. This filter hums a little, but I must put my ear right next to the speaker to hear it, so it is very quiet anyway. With lower R in CRC the soundstage is much bigger, sound seems to be faster, better bass, better details, instruments are more separate from their self. Why is that? I thought that better ripple rejection the better sound?

31st July 2009, 10:15 AM	#3
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	what is the R of the transformer and wiring feeding the CRC? You actually have an RCRC filter. If you try adding a little extra R before the first C you may hear something else. Even better, may be to replace part of the R with an air cored inductor (L+R). Adjust the fixed R values to give the desired (same) B+. Do ensure that B+ is the same in all the implementations when making your sound quality assessments. __________________ regards Andrew T.

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31st July 2009, 10:09 AM	#2
diy4 diyAudio Member Join Date: Jun 2004 Location: .	What was the original value of the resistor? Also, what were the DC voltages before, and after you changed the resistor?

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