I have built up a couple of boards that I sourced from BrianGT, ages ago.
It uses the LM3886 chip.
Until now I have used it mostly to fix older amplifiers ('80s stuff) that are not worth rescuing. For instance, the Technics SU-V2X where the original STK chips were detoriating.
Often these amplifiers have the correct voltages needed.
However, with my most recent effort I have a problem with hum, as seems te be normal. I only used the original volume potentiometer, and used shielded cables everywhere.
What I don't understand is that the hum goes away when I put the volume control in the middle.
Is there anybody that immediately knows the answer to this?
If not, I can always include the schematic (with cables and so on) and a few pictures. All wires are twisted of course.
One would guess it must be somewhere before the gainclone boards, because of the behaviour with the volume control.
It uses the LM3886 chip.
Until now I have used it mostly to fix older amplifiers ('80s stuff) that are not worth rescuing. For instance, the Technics SU-V2X where the original STK chips were detoriating.
Often these amplifiers have the correct voltages needed.
However, with my most recent effort I have a problem with hum, as seems te be normal. I only used the original volume potentiometer, and used shielded cables everywhere.
What I don't understand is that the hum goes away when I put the volume control in the middle.
Is there anybody that immediately knows the answer to this?
If not, I can always include the schematic (with cables and so on) and a few pictures. All wires are twisted of course.
One would guess it must be somewhere before the gainclone boards, because of the behaviour with the volume control.
With the volume control in the middle the input picks up hum which is out of phase with hum in amp and cancels it out.
Check amp is earthed.
If you have amp connected to something else which is earthed you can get earth loops.
One earth connection is good, zero or more than 1 earth connection is bad.
Check amp is earthed.
If you have amp connected to something else which is earthed you can get earth loops.
One earth connection is good, zero or more than 1 earth connection is bad.