How to connect a diy audio probe to an old receiver (cd in) ?

[Axelerator]

Hi, in my other actual thread i described my problem with my neve pultec clone.
I diyd myself an audio probe with a shielded chinch cable, tip via 0.68uf to signal plus, shield to ground of my old receiver , where i want to use the cd input.
As this is not working, i assume i would have to connect the shield to both grounds( test cuircuit  audio ground ) and chinch outer ring of my receiver ?
> what would lead to some humm but i should hear my test signal ?
or has the cd input a too high input impedance for this test ? maybe the filter formed by the cap and the input impedance cuts to much low and mid content , so i can hear nothing ?
thanks again..

i did ask in a new thread because i think this could be informative for all the other  people want to  test cicuits with an diy audio probe..

 

[abbey road d enfer]

Hi, in my other actual thread i described my problem with my neve pultec clone.
I diyd myself an audio probe with a shielded chinch cable, tip via 0.68uf to signal plus, shield to ground of my old receiver , where i want to use the cd input.
As this is not working, i assume i would have to connect the shield to both grounds( test cuircuit  audio ground ) and chinch outer ring of my receiver ?
> what would lead to some humm but i should hear my test signal ?
or has the cd input a too high input impedance for this test ? maybe the filter formed by the cap and the input impedance cuts to much low and mid content , so i can hear nothing ?
thanks again..

i did ask in a new thread because i think this could be informative for all the other  people want to  test cicuits with an diy audio probe..

You need to connect the audio grounds of the two units together; you may experience hum because of flawed design in one of the units. ther are solutions, but they involve the use of transformers or active circuitry.
for example:
http://www.bhphotovideo.com/c/product/380761-REG/Rolls_HE18_BUZZ_OFF_HE18_Buzz_Off.html
http://www.bhphotovideo.com/c/product/373746-REG/Behringer_HD400_MicroHD_HD400_Hum_Eliminator.html
http://www.bhphotovideo.com/c/product/813214-REG/RDL_EZ_HK1_EZ_HK1_Stereo_Audio_Hum.html

 

[Axelerator]

did this already after thinking a little bit ! i learn everyday something here , thats great !
as it is for tracing, humm is no problem.
Now i can work on my faulty channel !
without this probe and without  oscilloskope there would be no chance for me finishing my project .
already traced down the error to the eq board, where my signal stops.

and going on !
thank you for your answer and the links  !!