Volume Controls

KatieandDad · 17th November 2011, 03:48 PM

Where to go.

I've just built a 100K stepped Volume Control and to be honest I am very disappointed with the result. It uses Vale resistors but the switching noise and resolution is appaulling.

I want to head back back to traditional pots.

Which pots can be recommended ?

I bought a Noble 10K Linear Quad Pot with the idea of adding parallel 1K resistors as Rod Elliot suggests. This Noble pot is absolutely rubbish, channel lineraity is within 50% over most of its travel.

I was going to build a balanced volume control but I'm having enough difficulty getting a decent dual pot.

gk7 · 21st November 2011, 02:49 PM

Expensive but the best:
Multi-Channel Rotary Fader | Penny + Giles

Slightly cheaper:
Rotary Fader | Penny + Giles

pieter t · 21st November 2011, 03:43 PM

If you're into that sort of prices for a volume control you might also look what inductive volume controls have to offer.
IMHO these sound better than whatever potentiometer and provide a better impedance interface between source and load.

DF96 · 21st November 2011, 03:51 PM

Resolution is entirely up to the designer/builder. Switching noise may depend on contact materials and whether any DC is getting in. Also whether MBB or BBM switches.

Mooly · 21st November 2011, 03:53 PM

ALPS,
Is the blue velvet Alps still best price/performance pot?

forr · 21st November 2011, 04:25 PM

I've just built a 100K stepped Volume Control and to be honest I am very disappointed with the result. It uses Vale resistors but the switching noise and resolution is appaulling.

10 kOhm would probably have not given such a result.

vacuphile · 21st November 2011, 04:43 PM

@ Forr that's the first thing I thought when I started reading this thread. 100 K is way to high, which will translate into excessive noise.

At the other hand, a 10 K linear pot with a 1 K resistor between ground and sweep is a bit lowish.

I think it might be a good idea to resolder the stepped pot to a lower value first and see what happens.

vac

gk7 · 21st November 2011, 05:44 PM

100 k is slightly high, yes, but "way to high" and "excessive noise" is a broad generalization. Let´s say we have a gain stage with moderate gain and low current noise (FET input) then a 100k pot (which presents 25k source impedance worst case to the next stage) would be ok.

gk7 · 21st November 2011, 05:51 PM

Resitor noise:
Resistor Noise / Widerstandsrauschen

pieter t · 21st November 2011, 05:55 PM

The OP mentioned switching noise, maybe because of a bad switch, or a BBM type with some DC present; it is important to keep an eye on input impedance but I don't think that resistor noise is the issue here.

17th November 2011, 03:48 PM	#1
KatieandDad diyAudio Member Join Date: Nov 2011 Location: UK	Volume Controls Where to go. I've just built a 100K stepped Volume Control and to be honest I am very disappointed with the result. It uses Vale resistors but the switching noise and resolution is appaulling. I want to head back back to traditional pots. Which pots can be recommended ? I bought a Noble 10K Linear Quad Pot with the idea of adding parallel 1K resistors as Rod Elliot suggests. This Noble pot is absolutely rubbish, channel lineraity is within 50% over most of its travel. I was going to build a balanced volume control but I'm having enough difficulty getting a decent dual pot.

21st November 2011, 02:49 PM	#2
gk7 diyAudio Member Join Date: Oct 2007 Location: Vienna / Austria	Expensive but the best: Multi-Channel Rotary Fader \| Penny + Giles Slightly cheaper: Rotary Fader \| Penny + Giles __________________ Regards, Georg

21st November 2011, 03:53 PM	#5
Mooly diyAudio Member Join Date: Sep 2007	ALPS, Is the blue velvet Alps still best price/performance pot? __________________ ------------------------------------------------------- *A simulation free zone.* *Design it, build it, test it.*

21st November 2011, 04:43 PM	#7
vacuphile diyAudio Member Join Date: Apr 2011 Location: Seaside	@ Forr that's the first thing I thought when I started reading this thread. 100 K is way to high, which will translate into excessive noise. At the other hand, a 10 K linear pot with a 1 K resistor between ground and sweep is a bit lowish. I think it might be a good idea to resolder the stepped pot to a lower value first and see what happens. vac __________________ If my 15 V DC were the radius of the Earth, Mount Everest would be 1 meter tall.

21st November 2011, 05:44 PM	#8
gk7 diyAudio Member Join Date: Oct 2007 Location: Vienna / Austria	100 k is slightly high, yes, but "way to high" and "excessive noise" is a broad generalization. Let´s say we have a gain stage with moderate gain and low current noise (FET input) then a 100k pot (which presents 25k source impedance worst case to the next stage) would be ok. __________________ Regards, Georg


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21st November 2011, 03:43 PM	#3
pieter t diyAudio Member Join Date: Apr 2009	If you're into that sort of prices for a volume control you might also look what inductive volume controls have to offer. IMHO these sound better than whatever potentiometer and provide a better impedance interface between source and load.

21st November 2011, 03:51 PM	#4
DF96 diyAudio Member Join Date: May 2007	Resolution is entirely up to the designer/builder. Switching noise may depend on contact materials and whether any DC is getting in. Also whether MBB or BBM switches.

21st November 2011, 04:25 PM	#6
forr diyAudio Member Join Date: Dec 2004 Location: Next door	I've just built a 100K stepped Volume Control and to be honest I am very disappointed with the result. It uses Vale resistors but the switching noise and resolution is appaulling. 10 kOhm would probably have not given such a result.

21st November 2011, 05:51 PM	#9
gk7 diyAudio Member Join Date: Oct 2007 Location: Vienna / Austria	Resitor noise: Resistor Noise / Widerstandsrauschen __________________ Regards, Georg

21st November 2011, 05:55 PM	#10
pieter t diyAudio Member Join Date: Apr 2009	The OP mentioned switching noise, maybe because of a bad switch, or a BBM type with some DC present; it is important to keep an eye on input impedance but I don't think that resistor noise is the issue here.

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