Telmar said:[...] there is no chance to get a balanced-signal out of this unit! [...]
Telmar said:Yeah, but that´s easy to change. Simply throw everything out that´s not needed, like this ...
dmills said:Differential outputs can gain you 6db of noise performance if (and only if) the noise is dominated by the line receiver and the pickup in the wiring that is not cancelled sufficiently.
jdbakker said:Telmar said:[...] there is no chance to get a balanced-signal out of this unit! [...]
The output is balanced in +4dBu-mode. The impedance for both positive and negative outputs is the same: 1k in series with 10uF (assuming 0R opamp output impedance, which certainly isn't true for higher frequencies). The output is not differential, though, but having a differential output is much less important than having balanced impedances. Have a look at this Jensen application note for more details.
jdbakker said:Telmar said:Yeah, but that´s easy to change. Simply throw everything out that´s not needed, like this ...
But then your output includes all the common-mode noise that the DAC produces, and there's a good chance that imperfections in your cabling and the receiver will transform some of the CM noise to normal mode.
tchgtr said:Oh my, yes! I didn't notice those on my first look.
I sense a Digi-key order in my future...
Maybe it would be a good idea to double-up and make those non-polar.
Actually, I looked, and there are bi-polar Panasonics with those values at Digi-key!
dmills said:The caps at the input (C159,C167) do not need to be non polar as they have ~2.5V bias across them, and I would (If I did anything) just replace with a classier electrolytic (Good modern electros with a little bias across them are actually seldom the villain of the piece).
Bipolar might be appropriate at the output however (and reduce that build out resistor value IMHO).
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