Volume pot for line level stereo

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ExtraCredit1

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Joined 2012
#1
I looked and searched but could not find a clear answer.

I need to control the volume of a stereo iPod input before my amplifier.

I want a good quality volume pot I can mount in my project box. If it was weather resistant that would be a bonus.

Any suggestions?

Mike
 
#3
You need a dual gang (stereo) pot. The value isn't critical but somewhere in the 10K to 47K range is ideal. A "log" type is normally used for volume controls but either log or linear will work just fine.

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titch said:
Be careful !
I tried this going from my soundcard to active speakers
I bought a 10K Alps pot but it hasn't worked,the volume is still the same
Click to expand...

Sounds as though you haven't wired it correctly.

http://www.diyaudio.com/forums/parts/183917-potentiometer-connection-help.html

And posts #45 and #46 here,
http://www.diyaudio.com/forums/analog-line-level/167495-simple-stereo-gain-stage-3.html#post2223539
 
#5
Mooly,

Can you give me a model number and where to buy one? There are just so many options 🙂

Thanks!!

Mike


Mooly said:
You need a dual gang (stereo) pot. The value isn't critical but somewhere in the 10K to 47K range is ideal. A "log" type is normally used for volume controls but either log or linear will work just fine.

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Sounds as though you haven't wired it correctly.

http://www.diyaudio.com/forums/parts/183917-potentiometer-connection-help.html

And posts #45 and #46 here,
http://www.diyaudio.com/forums/analog-line-level/167495-simple-stereo-gain-stage-3.html#post2223539
Click to expand...
 
#7
That comes up as unavailable for me but it's the right kind of part. ALPS generally considered one of the best but it might be overkill for what you need.

Don't know what kind of outlets you have in your locality but any component retailer should have suitable parts and they needn't be expensive. Check out Mouser and Digikey in the US for all parts you'll ever need.

PC2G16ECO10KB - OMEG - POT, DUAL GANG, LOG, 10K | CPC

Here's a 22K "traditional" style. The connections are the same on any pot.
OW2G20BU22KB - OMEG - POT, DUAL GANG, LOG, 22K | CPC

2 x 10K OHM Logarithmic Dual Rotary Taper Potentiometer A10K 10KA POT ALPHA | eBay

You might be interested in this. Read the bit on potentiometer tapers and changing the law of a pot.

Potentiometers (Beginners' Guide to Pots)
 
#8
So I got the 10k Alps and there is no bass unless you are at almost full on the. I read somewhere else that the impedance of the pot to too high for my source. So should I buy a 5k pot?

Why is this so hard to get a line level volume pot for a iphone signal?? I would think a lot of people need this but I cant find any info.

Thanks!!
Mike
 
#9
You have not given us any data from which we could make estimates of what you have done wrong.

The volume pot behaves as a load on your source. While it does that duty there will be some form of filter created.

The volume pot behaves as a source for your next stage (Power amplifier, or Buffer or, ?) Again there is the possibility of a filter being created.

You need to tell us what the initial Source output parameters are and the final load input parameters.
 
#11
AndrewT said:
You have not given us any data from which we could make estimates of what you have done wrong.

The volume pot behaves as a load on your source. While it does that duty there will be some form of filter created.

The volume pot behaves as a source for your next stage (Power amplifier, or Buffer or, ?) Again there is the possibility of a filter being created.

You need to tell us what the initial Source output parameters are and the final load input parameters.
Click to expand...

My source is a Iphone and my amplifier is the IcePower 200AC. I can't find input impedance in specs.

Mike
 
#17
Depending on the output stage (Class D ?) of the ipod then it might be worth trying a parallel resistor across the outer pot terminals. In other words add a dummy load to the ipod. Maybe try around 33 ohm. The pot remains as it is. I believe some of these output stages rely in the low impedance of the h/phones to form the final stage of the low pass filter.

If that doesn't work and you still have no bass then there is a basic error or miscalculation somewhere.
 
#18
Mooly said:
Depending on the output stage (Class D ?) of the ipod then it might be worth trying a parallel resistor across the outer pot terminals. In other words add a dummy load to the ipod. Maybe try around 33 ohm. The pot remains as it is. I believe some of these output stages rely in the low impedance of the h/phones to form the final stage of the low pass filter.

If that doesn't work and you still have no bass then there is a basic error or miscalculation somewhere.
Click to expand...


Maybe I am over simplifying this but if my signal is lacking bass when in the lower area of the volume pot (which has more resistance) and sounds good at the top level of the pot (which has lower resistance) then wouldn't adding more resistance make it even worse?

MP
 
#20
DF96 said:
Is this bass actually lacking, or merely that you want more bass at low volumes? If the latter, then that is just due to what your ears do. Perhaps you are used to 'loudness' controls which automatically boost bass at low volumes?
Click to expand...


No I am pretty sure it is lacking in the bass. The last two clicks of the volume control don't increase the output level much but the bass goes up maybe 6-8db

Its just not right. And after reading the article on the sticky in this forum I understand why but I don't understand how to fix it. LOL
 
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