On Mon, 16 Feb 2015, Roger wrote:
On 16/02/15 11:51, Len Ovens wrote:
It seems even with all power coming from one outlet, I have one amplifier
with some hum. It is way less and by playing with levels I was able to make
it so low as to not be noticed. However my plan of isolating everything
should fix it completely.
Look at the signal cabling or even nearby EMF sources. I
recall ages ago
Over 100 ft of unbalanced input. The hum was not there with the power
ground lifted (now fixed). I will be Changing things so I have balanced
out of the mixer -> through snake -> one to one isolation transformer ->
unbalanced to amp.
My final setup will be: all stage powered instruments or unbalanced
sources will have a DI (transformer with ground lift), All returns to
stage will have isolation transformers. Mics go straight.
Anyway the hum was low enough that I had to tell people it was there, so I
am at "good enough". I do have two pots at max and one very low to get it
to work that way though. I will see what my isolation box does.
--
Len Ovens
www.ovenwerks.net