am I missing something- I tried made passive I/V (and lso active with opamp) WITHOUT SUMMING 1853 (or 1794) postive and negative current output phases. usuing opapam as IV (and in 1794 i used 22ohm resitors) output offset postive or negative phase to GND is whooping 5V according to Fluke tester(it works but my digital volume control is very unhappy-loud pops and clicks when adjusting sound ) I tried coupling caps for both phases (voltage goes down to 3V) even for ground- nothing helps. if I measure voltage betweet positive and negative i get only 1-3mV. i have laying dac with 4 x ad1853 which i would love to paralel for more current then convert I/V with resitor KEEPING BALANCED signal.
in the past i tried same trick with pcm1794 and it didnt worked also ( with 1794 voltages betwen +gnd and -gnd vere unequal, in ad1853 they at leat equal)
in the past i tried same trick with pcm1794 and it didnt worked also ( with 1794 voltages betwen +gnd and -gnd vere unequal, in ad1853 they at leat equal)
thanks, here it is.its interesting that music plays on xlr outputs (but DC ofset is showing 5V and there is loud crackling noise when i adjust volume with digital -analog atenuator-toshiba tc9459N) if i measure BETWEEN Balanced p[in 2 and 3- all perfect music plays(so pahses are opsosite does not cancel eatch other ) but there is no ground conection to conect it to balanced power amplifier.
Attachments
hi dkfan, its current output dac so there is no voltage at IV opams noniverting input. non iverting inputs are just grounded -that opamp can convert current to voltage. power suply of opamps is +-15V.
in the past i had same problems on pcm1794 dac where i use non opamps for IV, jsut 22ohm resitors as I/V. same problem(just dc ofset was not equal postiive and negative referenced to GND - like here on ad1853 -where they equal.) once both postive / negative summed with opamp- all fine.. but no balanced then. strange.
in the past i had same problems on pcm1794 dac where i use non opamps for IV, jsut 22ohm resitors as I/V. same problem(just dc ofset was not equal postiive and negative referenced to GND - like here on ad1853 -where they equal.) once both postive / negative summed with opamp- all fine.. but no balanced then. strange.
if i understand corectly, I should measure DC voltage across both inputs of each opamp(as positive input tied to ground)?