Yes, you´re right. The opamp boards layout is not the same, same circuit though
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- Thread starter Igor
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Trying to trace my own 33609 PCBs based on original schematics.
Have a couple of questions.
In original layout, some signals are "screened" with ground tracks coming around.
I only found one good photo of the upper side of Comp/Limit PCB and judging from here
P2-6 (gain makeup) and P2-4 (compress switch HIGH) signals are surrounded by ground tracks.
Also, according to schematics, signal outputs P3-9, P3-10 must be screened, but seems like they are on the bottom side, so I can't examine these.
Also P2-9 (compress ratio), P2-3, P2-4 (compress switch LO, HI), P1-5 (comp threshold) must be screened, but as I see on the front side,
P2-3 (compress switch LO) is traveling through the board without any ground traces (I've marked this track with UP arrow and question sign).
My whole question is, is it necessary needed ? Does it save the signals from interference that much ? Shall it create unwanted ground loops ?
It would be cool if somebody have a bottom layer photo or layout to watch.
Thank you !
Have a couple of questions.
In original layout, some signals are "screened" with ground tracks coming around.
I only found one good photo of the upper side of Comp/Limit PCB and judging from here
P2-6 (gain makeup) and P2-4 (compress switch HIGH) signals are surrounded by ground tracks.
Also, according to schematics, signal outputs P3-9, P3-10 must be screened, but seems like they are on the bottom side, so I can't examine these.
Also P2-9 (compress ratio), P2-3, P2-4 (compress switch LO, HI), P1-5 (comp threshold) must be screened, but as I see on the front side,
P2-3 (compress switch LO) is traveling through the board without any ground traces (I've marked this track with UP arrow and question sign).
My whole question is, is it necessary needed ? Does it save the signals from interference that much ? Shall it create unwanted ground loops ?
It would be cool if somebody have a bottom layer photo or layout to watch.
Thank you !
I can’t comment on the original layout and I don’t have schematic at hand, but here’s what I encountered. Some parts of the circuit are quite high impedance, and signals may “leak” quite easily between these tracks. This happened to my boards and led to oscillation in some settings. I ended up using grounded polygon pours that essentially screened all tracks. This cured the oscillation problem completely.
So yes. I’d say it’s important to screen high impedance parts of this circuit to avoid leakage.
So yes. I’d say it’s important to screen high impedance parts of this circuit to avoid leakage.
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