Build question

[Doc B.]

If you have the output transformer wired for 32 ohms, some more sensitive headphones will pickup a little hum. You can fix that by reconfiguring the output transformer to 16 or even 8 ohms without any real sonic penalty.

[odamone]

Thanks for the tip. I have the AKG K702 and the Beyerdynamic DT770 PRO 250ohm version. I assume the latter isn't sensitive, but both of these suckers require nearly no volume.

I also noticed that the left channel comes in first / louder than the right as the volume is turned up slowly from zero. I don't detect a misbalance at listening volume. Is that normal?

[adamct]

Yes. Almost all stereo potentiometers have channel imbalance at low volumes. True, some are better than others, but it is pretty much inherent in the way they are constructed. But at normal volume levels it should be fine. If you frequently find yourself listening at low volume levels, you can install resistors on the inputs or use signal attenuators, which will let you listen at a hire volume level.

Or...you can install a $25 stepped attenuator, since stepped attenuators don't have channel imbalance issues.

[odamone]

Thanks! I love this forum. I have lots to learn, thanks for helping.

[adamct]

LOL...."hire volume level"...

[forehead slap] 

[odamone]

Ha, I totally missed that.