adjusting a pots output

[arlis_1957@yahoo.com]

i installed a 50k alps pot the my new amp and turned all the way down, its just right. all the way up and it will blow me out of the room.
question; can i put an inline resistor, maybe 10 or 20 ohms to atenuate it a bit? would a cast 10 watt be good for this?

[jcpahman77]

Re: adjusting a pots output

values of 10 or 20 in series will allow you to dial it in until you find a value that when added won't blow you out of the room. As to the wattage whatever the alps pot is rated for should be suitable for the added resistor since they'll be in series.

[arlis_1957@yahoo.com]

Re: adjusting a pots output

thanks guess i should have got the 100k

[jcpahman77]

Re: adjusting a pots output

Hindsight right? The thing is... I don't think that's the problem. Turned all the way up (the highest volume level) both pots would read 0 ohms, the difference would be how much attenuation all the way down would be, and you've stated the 50k is satisfactory, so it seems adding some resistance after the pot is the right method.

[arlis_1957@yahoo.com]

Re: adjusting a pots output

just right for listening but i cant turn it down to here what the wife just said. that could get me in trouble.

[50 watt head]

Re: adjusting a pots output

The description you've given is slightly unclear. But, you may want to try a 10K or 25K or 50K (etc.) resistor in series BEFORE the pot and see if that helps you get what you're looking for.

i installed a 50k alps pot the my new amp and turned all the way down, its just right. all the way up and it will blow me out of the room.
question; can i put an inline resistor, maybe 10 or 20 ohms to atenuate it a bit? would a cast 10 watt be good for this?

[arlis_1957@yahoo.com]

Re: adjusting a pots output

yes i think your right. i suppose the input voltage is so high that a 50k wont do so i should turn it into a 100k by adding a 50k before it. wow, i think im beginning to make sence!

[Sydney]

Re: adjusting a pots output

thanks guess i should have got the 100k

What kind of taper did you use?

[arlis_1957@yahoo.com]

Re: adjusting a pots output

audio/log taper.
this one. http://www.partsconnexion.com/product7387.html

[Ron_E]

Re: adjusting a pots output

i installed a 50k alps pot the my new amp and turned all the way down, its just right. all the way up and it will blow me out of the room.

Turned all the way down you shouldn't hear anything if this is an input level control. One side of the pot should be at ground and the other side should have the input signal and with the control turned down the output (the pots wiper) should be at ground too. Adding series resistance to the input signal side will form a voltage divider and attenuate the output and yes the size of the resistor will be in the K-ohms to do anything meaningful.

Another thing you need to watch with attenuators is unless they have a resistive load you could be creating a filter in which case you may need to consider and active buffer.

Ron

[arlis_1957@yahoo.com]

Re: adjusting a pots output

i did not tie to the ground. just input and wiper. could that be the problem?

[Ron_E]

Re: adjusting a pots output

i did not tie to the ground. just input and wiper. could that be the problem?

Yes. The way you wired it you're just adding series resistance to the input of the amp. The pot should be a voltage divider with the signal attached to one end and ground connected to the other and the wiper as the output.



Ron

[Ron_E]

Re: adjusting a pots output

PS The way you wired it with the volume turned all the way one way you would be running the signal in with zero attenuation which would be as loud as it can go. With the pot all the way the other way you put 50K in series with the input which made it quieter but didn't short the input to ground like you want to do.

Ron

[arlis_1957@yahoo.com]

Re: adjusting a pots output

got it. thanks ron.

[arlis_1957@yahoo.com]

Re: adjusting a pots output

i tied everything and it made no difference. just for s &g's i added 45 ohms before the pot and it made no difference. now i wonder, is the center of a rca pos or neg. i have white on the center black on the outside. whites only through the source switch and vol pot. extra resistors on the white.