porthillsbomber
Head-Fier
- Joined
- Jul 21, 2010
- Posts
- 73
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- 11
yeah sort of... no. The key thing to not getting cross talk is using a difference amplifier to take the difference between input signal and input ground and then referencing it to your final output ground.
Also the reason I would use this whole ABG method is to make clipping sound better but with beta22 you will get nowhere near clipping so I wouldn't bother, I don't quite understand Meier's reasoning so there may be a point to do what you propose provided what he says is correct.
Just to clear things up lets call your first circuit active balanced ground (ABG) because the ground is active just like an ordinary active ground as it seperates the headphone return current (OG) from the signal currents on the left/right channel opamps. This is a perfectly fine circuit as long as the gains are well matched.
Let's call mine balanced ground (BG) as the OG is connected to the signal currents on the left/right opamps, kind of like when you just have your 3rd opamp just buffering the ground in a standard opamp amp. This method does not rquire the gains to be well matched as the left/right outputs are referenced to OG.
Both methods also need to be feed with a low output impeadance source (which can be done with an input buffer as we both tried) to insure low crosstalk regardless of whether the gains are well matched or not.
I hope this makes sense, I may have to draw some diagrams to make things clearer.
Also the reason I would use this whole ABG method is to make clipping sound better but with beta22 you will get nowhere near clipping so I wouldn't bother, I don't quite understand Meier's reasoning so there may be a point to do what you propose provided what he says is correct.
Just to clear things up lets call your first circuit active balanced ground (ABG) because the ground is active just like an ordinary active ground as it seperates the headphone return current (OG) from the signal currents on the left/right channel opamps. This is a perfectly fine circuit as long as the gains are well matched.
Let's call mine balanced ground (BG) as the OG is connected to the signal currents on the left/right opamps, kind of like when you just have your 3rd opamp just buffering the ground in a standard opamp amp. This method does not rquire the gains to be well matched as the left/right outputs are referenced to OG.
Both methods also need to be feed with a low output impeadance source (which can be done with an input buffer as we both tried) to insure low crosstalk regardless of whether the gains are well matched or not.
I hope this makes sense, I may have to draw some diagrams to make things clearer.