Hello.
I just made a cmoy headphone amp and the pot only seems to work for the first 1/5th of its travel. any advice on how to find out what is wrong here? bad pot?
>>946317
You probably have a linear taper pot. You need a logarithmic pot (audio pot).
if you mean that the thing goes to max volume at 2 instead of 11, it means your gain is too high, or your input level is too high. (both situations mean the same thing, really). if so, since there are so many 'CMOY' designs, it's impossible to say what needs changing.
>>946327
i used this guide:
http://tangentsoft.net/audio/cmoy/
i tested at very low input levels and high input levels it just seems to add about 3db at 1/5th pot travel then doesn't get louder after that. works fine before then.
>>946322
ill try swapping with an audio pot, not sure if the one is have is linear or not, thanks for the tips.
>>946329
>not sure if the one is have is linear or not
>Remove it from circuit
>Turn it to the half way point
>Measure from centre pin to both sides
If they are about equal its linear.
>>946329
it's a weird design. it uses two 9V batteries in series, but instead of using the center point as ground, they make a useless virtual ground using 2 large caps. seems retarded to me.
anyway, the page you linked to has a tip that addresses your issue exactly. it tells you how to adjust the gain so your pot has an effect over its full range.
>>946334
ahh thanks
>>946334
Using two caps to create a virtual ground will eliminate the problems with uneven voltage and drain from your batteries, which will make for a shitty ground.
>>946354
yeah, in theory, assuming the output signal is high enough, say 7V, that a weak battery could play a role. however, a headphone amp puts out maybe 0.2Vp which is 1/35-th of what you'd need for it to be a problem.
>>946317
Hey KipKay ;^)
>>946368
Hey, David. Has your bum-hole healed since out last encounter?
