50K vs 100K POT

ss1 · 19th July 2004, 05:33 PM

Hello ,
i'm a newbie. I just upgraded my pot from alps 100k (radio shack) to 50k alps black pot and I noticed that the sound got louder. Should I switch back to a 100k pot to better control the volume? Curious, how much volume can a 100k vs 50k pot lower by? or can i add a 10k resistor to the 50k pot to lower the volume? any comments?
thanks

Richard C · 20th July 2004, 12:20 AM

The value of the pot if wired correctly shouldn't make any difference to the volume. It's the ratio of the resistances either side of the pot wiper that set the output level not the absolute value of the pot.

Centauri · 20th July 2004, 11:18 AM

If the original pot was logarithmic taper (most likely), and the pot you used to replace it is linear taper, then new pot will be louder at settings below full volume. Log taper varies the volume by increasingly larger amounts to compensate for the way our ears hear volume changes.

Cheers

rabbitz · 20th July 2004, 12:48 PM

If it's a 50k linear, use Rod Elliott's law-faked volume control by adding a 7.5K resistor to ground. See the details at Rod's site.

http://sound.westhost.com/project01.htm

ss1 · 21st July 2004, 02:58 AM

thanks everyone for the info that explain the problem. the new pot is good but it's loud.

Do i wired the resistor like this
http://sound.westhost.com/p01-f1.gif

what kind of resistors should i use riken, mills,etc?
thanks again

rabbitz · 21st July 2004, 02:01 PM

Yeah, that's the circuit.

Resistor goes between the output and ground (centre pin to ground). All that is specified is 1% metal film resistors and I'm sure there are benefits from using a higher quality resistor. I think the better the quality the less noise.

ss1 · 21st July 2004, 08:42 PM

hello
according to the diagram, i have to wired the resistor before the signal reach the pot?

flow diagram
1)input signal -> 2)resistor -> 3) pots -> 4) output signal (going to amp)

thanks

rabbitz · 22nd July 2004, 01:57 PM

I see where you are coming from as the diagram is a bit misleading as the arrows appear to point the opposite way. Reverse the arrow directions and that's the signal direction.

If you look at the pot from the front (shaft pointing towards you), the first connector on the left is #1, centre #2, right #3.

#1 is ground
#2 is output
#3 is input

See this pic: http://sound.westhost.com/pots-f5.jpg

Resistor goes from #2 (output) to ground. This only works for a linear (B) pot and not a log (A) pot. Was a lot easier when a manufacturer included that info in the part number such as AX2 would be a dual gang log pot and a BX2 would be a dual gang linear pot.

Hope this clears it up for you.

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19th July 2004, 05:33 PM	#1
ss1 diyAudio Member Join Date: Jan 2009	50K vs 100K POT Hello , i'm a newbie. I just upgraded my pot from alps 100k (radio shack) to 50k alps black pot and I noticed that the sound got louder. Should I switch back to a 100k pot to better control the volume? Curious, how much volume can a 100k vs 50k pot lower by? or can i add a 10k resistor to the 50k pot to lower the volume? any comments? thanks

20th July 2004, 12:20 AM	#2
Richard C diyAudio Member Join Date: Jul 2003 Location: Nottingham, England	The value of the pot if wired correctly shouldn't make any difference to the volume. It's the ratio of the resistances either side of the pot wiper that set the output level not the absolute value of the pot.

20th July 2004, 11:18 AM	#3
Centauri diyAudio Member Join Date: Jul 2003 Location: Newcastle, Australia	If the original pot was logarithmic taper (most likely), and the pot you used to replace it is linear taper, then new pot will be louder at settings below full volume. Log taper varies the volume by increasingly larger amounts to compensate for the way our ears hear volume changes. Cheers

20th July 2004, 12:48 PM	#4
rabbitz diyAudio Member Join Date: Jul 2003 Location: Newcastle	If it's a 50k linear, use Rod Elliott's law-faked volume control by adding a 7.5K resistor to ground. See the details at Rod's site. http://sound.westhost.com/project01.htm

21st July 2004, 02:58 AM	#5
ss1 diyAudio Member Join Date: Jan 2009	thanks everyone for the info that explain the problem. the new pot is good but it's loud. Do i wired the resistor like this http://sound.westhost.com/p01-f1.gif what kind of resistors should i use riken, mills,etc? thanks again

21st July 2004, 02:01 PM	#6
rabbitz diyAudio Member Join Date: Jul 2003 Location: Newcastle	Yeah, that's the circuit. Resistor goes between the output and ground (centre pin to ground). All that is specified is 1% metal film resistors and I'm sure there are benefits from using a higher quality resistor. I think the better the quality the less noise.

21st July 2004, 08:42 PM	#7
ss1 diyAudio Member Join Date: Jan 2009	hello according to the diagram, i have to wired the resistor before the signal reach the pot? flow diagram 1)input signal -> 2)resistor -> 3) pots -> 4) output signal (going to amp) thanks

22nd July 2004, 01:57 PM	#8
rabbitz diyAudio Member Join Date: Jul 2003 Location: Newcastle	I see where you are coming from as the diagram is a bit misleading as the arrows appear to point the opposite way. Reverse the arrow directions and that's the signal direction. If you look at the pot from the front (shaft pointing towards you), the first connector on the left is #1, centre #2, right #3. #1 is ground #2 is output #3 is input See this pic: http://sound.westhost.com/pots-f5.jpg Resistor goes from #2 (output) to ground. This only works for a linear (B) pot and not a log (A) pot. Was a lot easier when a manufacturer included that info in the part number such as AX2 would be a dual gang log pot and a BX2 would be a dual gang linear pot. Hope this clears it up for you.

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