Low Output in Left Channel, Possible Causes?

[Inz]

I have a fubar III usb dac/amp from firestone audio and realized that, at very low volumes, the left channel is significantly quieter. At normal listening volumes it is not noticeable, but I'd still like to know what could be causing it.

I have tried to isolate the problem and know for certain that it is not my headphones. Is it likely to be a problem with the attenuator (volume know) or somewhere else in the circuit (i.e. opamp, etc).

I'm really curious as I am seriously considering starting in DIY, probably Starving Student to get practice then a Bottlehead S.E.X..

Thanks

[tomb]

Originally Posted by Inz

I have a fubar III usb dac/amp from firestone audio and realized that, at very low volumes, the left channel is significantly quieter. At normal listening volumes it is not noticeable, but I'd still like to know what could be causing it.

I have tried to isolate the problem and know for certain that it is not my headphones. Is it likely to be a problem with the attenuator (volume know) or somewhere else in the circuit (i.e. opamp, etc).

I'm really curious as I am seriously considering starting in DIY, probably Starving Student to get practice then a Bottlehead S.E.X..

Thanks

If the channel matching is OK at higher volumes, it's likely that the pot is not tracking well at low settings. It's one of the reasons so many DIYers use the ALPS RK27 when building amps.

Tangent did some excellent testing work on various pots: Notes on Audio Attenuators. It kind of shows you how it can be a common issue with many pots.

[Inz]

Thanks tomb! I am guessing that is the case... oh well. Now this gear is just a holdover until I can build some better stuff... ha.