Adding a Potentiometer

[col]

go the whole hog and build a preamp with a nice input selector. You mentioned you had multiple sources.

http://sound.westhost.com/project88.htm

col.

 

[Havoc08]

Have I understood this right?

The preamp in the link differs from an ordinary pot because the linked pot in preamp is not in the audio path, but functions as a divider network, where as normal pots are in the signal path?

Also I would be nice to adjust gain from sources to give same output SPL on same amp setting so changing from mp3 to dvd doesn't blow speakers 😉.

Input selection is done via rotary button and not via relay or similar right (which is better?) ?

 

[AndrewT]

Hi,
are you referring to fig3?

The pots work as normal attenuators.

The wiring of the balance pot is a bit unusual, but I disagree with ESP, it is in the audio path. It is the law faking resistor made adjustable and as such very much affects the final output signal from the pots to the next stage. The fact that the law faking resistor has been made adjustable does not remove it from the audio path. It passes audio signals.

 

[Havoc08]

yes I'm referring to fig 3.

So in your opinion andrew, the sound quality is similar when comparing the esp volume control with a good pot like DACT or similar?

Only other thing appealing to me is the possibility to adjust gain from different sources, but the price is of course more managable with a normal pot 🙂.

 

[AndrewT]

So in your opinion andrew, the sound quality is similar when comparing the esp volume control with a good pot like DACT or similar?

where did that conclusion come from?
I certainly did not say anything even remotely similar to what you have attributed to me.

 

[Havoc08]

hmm wait a minute.. maybe I have read it wrong... You can adjust gain on preamp but not on individual inputs? Is this correct?

 

[Havoc08]

The wiring of the balance pot is a bit unusual, but I disagree with ESP, it is in the audio path. It is the law faking resistor made adjustable and as such very much affects the final output signal from the pots to the next stage. The fact that the law faking resistor has been made adjustable does not remove it from the audio path. It passes audio signals.

I'm reading this as if you disagree with esp and that the resistors are still in the audiopath like a normal pot?
Hence the esp solution is not necessarily better than a good pot if I don't need the gain option?

please note that is is not a conclusion, but a question of whether I understood your statement correctly (hence the question mark 😉 ).

 

[AndrewT]

I disagree with ESP.
The pots, all three of them, are in the audio path and pass audio signals.

 

[col]

Iv'e been looking at this for a while and wondering if it would be a good alternative to a standard dual-gang volume pot. Maybe it's time to try one:

http://www.ska-audio.com/diy/optivol.html

AndrewT, what would be your opinion on this method?

cheers,
col.

 

[Redshift187]

That is similar to a project known as the "lightspeed attenuator". Search for it and you will find it 🙂