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geoff geoff is offline
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Default Where does the hum come from?

On 12/02/2021 2:02 am, Scott Dorsey wrote:
geoff wrote:

Look at the picture in the OP link. RCA unbal outputs.


I have no graphics here. So RCA on one end, what is on the other end?


No graphics ? This *is* the 21st Century ! Or are you working on one of
these ? ;- )

https://www.facebook.com/photo/?fbid...57424488371333

(for the insecure the link is to a picture on Facebook of a computer).


If the RCA connector is run to pins 2 and 3 of an XLR on the other end
with pin 1 lifted (as is a common and reasonable configuration), then
the case of the powered speaker won't be connected to the case of the
DAC until power is applied. So in that case the thing would hum in the
configuration the original poster describes.

But without knowing what the cable is, you don't know for sure.
--scott

Well can be sure it isn't a twin untwisted heavy-gauge speaker cable !

The LSR305 has bal (and equally unbal) jack and XLR inputs. At least
mine have, and no hum even when connected via several intermediate
devices to a PC, a mixture of bal and unbal.

Would help to know the 'quality' and make-up/configuration of the
RCA-to-whatever cable.

geoff