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Old 18th July 2005, 06:19 AM   #1
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Talking What pot should i use?log or linear for 3886?

HI guys, i have been build 3886 amp, but i found strange problem. I hear a normal sound (not too loud) at half of volume, but in my 1875 amp , i use linear pot and i hear a the same sound only a quarter of my volume.
So what should i use pot or log??Which one is better???
And how to eliminate hum sound???Actually i use star grounding, but i still hear quite hum sound.
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Old 18th July 2005, 07:24 AM   #2
digi01 is offline digi01  China
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with same LSP?
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Old 18th July 2005, 07:49 AM   #3
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Even better than a log pot is using a linear pot and an additional resistor.

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Old 19th July 2005, 05:48 AM   #4
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of course i use the same loudspeaker.
My 3886 GC's have 23x gain, it should be loud at quarter of the volume.
I want to ask about ur opinion,can 3886 GC beats some branded amplifier?like NAD??
My input cap is 4,7uF rubycon, is it good??what's happened when i use above 4,7uF?will cut some frequency??
What is the different (my mean in sound character) between using input cap which have 50V rating with other cap which have higher voltage??
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Old 20th July 2005, 01:17 PM   #5
drbobee is offline drbobee  Hungary
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Quote:
My input cap is 4,7uF rubycon, is it good??what's happened when i use above 4,7uF?will cut some frequency??
It is Good. Will not cuts frequency... so freq human ears can hear, but if you want to 0,05-3Hz hear, place bigger one, for example 470uF
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Old 22nd July 2005, 07:16 AM   #6
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about input capasitor, if i use an expensive cap like blackgate-N/auricap does it give an effect to the sound, which we can hear???
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Old 25th July 2005, 09:55 PM   #7
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I use a resistor in the signal (5k) and
a log pot as variable resistor from signal to ground.
This gives an excellent sound. Volume control is
a little more touchy but the sound is great.

I'm sorry an NAD amplifier does not sound so great.
I'm using LM3875s. They easily outperform an
NAD as long as you do match power and impedance.

It all depends on your layout. You will need high
quality resistors. And a decent power supply. In
all my experiences adding an input buffer helps a
lot.

Personally I did not find much difference with the
input caps. I did find a large effect of the resistors.
Personally I like Holco H8 and Vishay s102 (The latter
one is too expensive for me).

If you use a DC blocking cap from -V to ground you
will need more then 4.7 uF. I found a 3 dB cut off
with 4.7uF. With bookshelf speakers this is desirable.
If you use full range speakers I recommend to go to
25uF or higher (You can also give it a switch and
allow to switch between full range and satelite speakers).

Harry
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