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Old 11th September 2007, 02:33 AM   #1
Leolabs is offline Leolabs  Malaysia
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Arrow Which parameter of the filtering caps do influence the sound of a gainclone???

Often heard that different caps,different sound,esp Gainclone.So which part of a capacitor datasheet so be looking at???
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Old 11th September 2007, 03:41 PM   #2
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Ah, the $64,000 question :-)

Many folk prefer smaller caps and attribute this to the higher slew rate (or lower rise time) compared to larger electrolytics.

Personally, I've had more success with sikorels than any other large cap. Sikorels are supposed to have a much higher slew rate than standard caps, which would seem consistent with this explanation.

But I really don't know (I haven't the scientific training to speak with authority) so maybe I've got it completely wrong.

Either way, the sikorels kick *** :-)
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Old 11th September 2007, 05:07 PM   #3
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Uh, capacitance?

I_F
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Old 11th September 2007, 05:45 PM   #4
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I like to use small caps as possible, and CHEAP ones, I think that is a WASTE use those very expensive caps. For input, if you have a 22k of resistor to the ground, a 1uF cap is MUUUCCHHH more than enought, the low frequency roll of is 7,23Hz. So, a 470nF cap would be MORE than enough, giving a roll of frequency of 15Hz. Can you hear 15Hz? I don't think so.

With the 470nF cap + 22k resistor, you have a 6Db/oct high pass filter for subsonic frequencies, it will help the amp to not waste power, and also be better for the driver.

470nF cap, you can get a CHEAP WIMA and you'll be VERY happy with this.

So, WHY use expensive and large caps for the input?

I many things that I design, when I'm dealing with impedances such 100K, I use 100nF caps, I have no problems with this, and 100nF caps you can get WIMA or EPCOS inexpensive caps...

So, I think that many people should reconsider the usage of large and expensive capacitors.
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Old 11th September 2007, 06:01 PM   #5
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Quote:
Originally posted by -_nando-_
I like to use small caps as possible, and CHEAP ones, I think that is a WASTE use those very expensive caps. For input, if you have a 22k of resistor to the ground, a 1uF cap is MUUUCCHHH more than enought, the low frequency roll of is 7,23Hz. So, a 470nF cap would be MORE than enough, giving a roll of frequency of 15Hz. Can you hear 15Hz? I don't think so.
I don't know about the sound of capacitor, but with those kind of -3dB points.... what about the phase distortion? I wont pretend to know exactly how it affects things etc, I have just read that it exists

LTSPICE tells me that 470nF and 22k and at 20Hz the phase will be... 37 degrees... whereas with say 3.3uF and 22k at 20Hz the phase will be... just 6 degrees. I use 3.3uF and 47k, which gives .... 3 degrees.
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Old 11th September 2007, 06:20 PM   #6
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Wow, I didn't know about this !
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Old 12th September 2007, 12:21 AM   #7
BWRX is offline BWRX  United States
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Default Re: Which parameter of the filtering caps do influence the sound of a gainclone???

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Originally posted by Leolabs
Which parameter of the filtering caps do influence the sound of a gainclone???
The price!!!
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Old 12th September 2007, 01:13 AM   #8
Leolabs is offline Leolabs  Malaysia
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Guys,I was asking about filtering caps,NOT signal coupling caps.
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Old 12th September 2007, 07:46 AM   #9
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A quote from TNT-Audio:

"By way of example, a typical commercial value capacitor, rated at 10,000uF/63V and costing some Euro 8-9, will have a speed of 30-40V/uS at best. An equivalent Elna for Audio series black, costing some Euro 15-25, will have a speed in the range of 80-90V/uS, i.e. at the very worst, double the speed of the best case in commercial cap land. A Siemens Sikorel cap, costing some Euro 20-30, will slew at over 100V/uS - but at a price."

http://www.tnt-audio.com/clinica/ssps1_e.html

As I said before, I can't say if this is primarily responsible for my preference for these caps in gainclones.
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Old 12th September 2007, 06:07 PM   #10
AndrewT is offline AndrewT  Scotland
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Hi,
I set the input high pass filter to between 1Hz and 2Hz. (RC~=90mS)
I then set the NFB filter to 0.7Hz to 1.4Hz (RC~=130mS)
Then the PSU filter should be set to 0.5Hz to 1Hz. (RC~=180mS).
for 8ohm speakers this requires +-20mF per channel and for 4ohm speakers +-40mF per channel.

I can hear the difference between input RC=90mS and RC=20mS.
I don't know if I am hearing phase improvement or frequency extension. What I do know is that even with small speakers they sound more realistic with the F-3db<=2Hz.
They also sound as though they go deeper and also sound stronger in the very low bass. I do not experience any reduction in bass quality when setting the high pass filter as suggested.

To me, it appears that all the filters are complementary and MUST be set low to get the best out of the signal and out of the speakers.
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