[gojira_matt]

First of all, apologies to be creating yet another cmoy thread. I've now built three of the buggers, and yet there is always something that seems to need tweaking/could be better. The latest one is almost exactly to Tangent's instructions, but with bigger caps and a gain of 6.

If anyone could help me with my two latest issues, I'd be most grateful.

Firstly, I have a bit of hiss. This stops when the source is disconnected, and also goes up and down with the volume. Any ideas what the source of the hiss could be?

And secondly, I accidently built my first one with a linnear pot, and as a result the volume change is of course linear. For my third one I have used a log pot, and yet it doesn't perform that differently to the linear pot. When the sound is turned all the way down, I still have some coming out of the headphones. Then, as I turn it up (very slowly) it gets softer, then louder in the left channel, and then the right, and then after that there is not much change in volume for the rest of the sweep. The pot I'm using is just a standard 9mm 10k pot from Jaycar here in Australia. Any ideas why it could be acting like it is?

Thanks again

 

[kvant]

> I have a bit of hiss. This stops when the source is disconnected, and also goes up and down with the volume. Any ideas what the source of the hiss could be?

Looks like the hiss behaves just like music. That would suggest that its source is the source.

> ...I have used a log pot, and yet it doesn't perform that differently to the linear pot... Any ideas why it could be acting like it is?

This is really just a speculation: some (many?) cheap log pots are not really logarithmic but piece-wise linear, channel tracking is often rather bad close to maximum attenuation. Perhaps you just experience a low quality pot. On the other hand, it could probably also be due to the pot being wrongly wired. Check again that wiper pin is really what you think is the wiper pin.

 

[gojira_matt]

Oh kvant, you're a wizard. Of course I had my pot wired incorrectly, and of course I've always wired them incorrectly. And that must have been where the hiss was coming from as well, because it's gone too. Thanks very much.