Pot question

Reklats · 4th December 2004, 07:40 PM

I've built a few different unbuffered gainclones so I could play with different designs, but I have a gaping hole in my gainclone knowledge:

With a pot gainclone like the one depicted on the national datasheet, when the volume is zero, wouldn't the signal be shorted to itself? I know the signal ground is attached to the power ground, but is it bad for the source to have its outputs shorted?

Right now I have a small resistor between the pot and ground to prevent disasters, so my volume only goes down most of the way.

Upupa Epops · 4th December 2004, 08:23 PM

Have you connected source on collector of pot ? !

mcs · 4th December 2004, 11:44 PM

If you connect the pot in the normal way, the input of your poweramp will be shorted, not the output of the source. The source will see the value of the pot as a load.

Best regards,

Mikkel C. Simonsen

jackinnj · 5th December 2004, 01:45 AM

given the power supply voltage etc. you adjust the potentiometer for an "optimal" distortion -- if you have a scope use a 1V 1kHz source and adjust the pot until the waveform starts to clip --- then back off. To be a lot more precise, if you have a distortion analyzer you adjust the pot (and this assumes that you are using a high quality source) for distortion of about 0.01% at 1kHz.

Reklats · 5th December 2004, 02:06 AM

While searching to see which pin the collector is I figured out how I was supposed to have it wired, so problem solved.

Thanks.

4th December 2004, 07:40 PM	#1
Reklats diyAudio Member Join Date: May 2004 Location: Ohio	Pot question I've built a few different unbuffered gainclones so I could play with different designs, but I have a gaping hole in my gainclone knowledge: With a pot gainclone like the one depicted on the national datasheet, when the volume is zero, wouldn't the signal be shorted to itself? I know the signal ground is attached to the power ground, but is it bad for the source to have its outputs shorted? Right now I have a small resistor between the pot and ground to prevent disasters, so my volume only goes down most of the way.

4th December 2004, 11:44 PM	#3
mcs diyAudio Member Join Date: Aug 2003 Location: Denmark	If you connect the pot in the normal way, the input of your poweramp will be shorted, not the output of the source. The source will see the value of the pot as a load. Best regards, Mikkel C. Simonsen __________________ My personal electronics website Remote control kits website

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4th December 2004, 08:23 PM	#2
Upupa Epops diyAudio Member Join Date: Aug 2003 Location: Prague,Czech Republic	Have you connected source on collector of pot ? !

5th December 2004, 01:45 AM	#4
jackinnj diyAudio Member Join Date: Apr 2002 Location: Llanddewi Brefi, NJ	given the power supply voltage etc. you adjust the potentiometer for an "optimal" distortion -- if you have a scope use a 1V 1kHz source and adjust the pot until the waveform starts to clip --- then back off. To be a lot more precise, if you have a distortion analyzer you adjust the pot (and this assumes that you are using a high quality source) for distortion of about 0.01% at 1kHz.

5th December 2004, 02:06 AM	#5
Reklats diyAudio Member Join Date: May 2004 Location: Ohio	While searching to see which pin the collector is I figured out how I was supposed to have it wired, so problem solved. Thanks.

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