Preamp filtering stage

[joesatch]

Is it beneficial (with plate voltage being equal) to have a B+5 vs a B+4 on the beginning stages of the preamp?

[HotBluePlates]

Is it beneficial (with plate voltage being equal) to have a B+5 vs a B+4 on the beginning stages of the preamp?

AC ripple is already exceedingly small in any preamp filter node you've likely encountered.

Someone might choose to have additional filter stages in a preamp when they're concerned about interactions between stages sharing a supply node, or when very high gain is present.

In such cases, another resistor & cap is not about "filtering ripple" but rather about "killing audio that's leaking from one stage to another."  Said a different way, it's about isolating one stage from another.

[joesatch]

would it be better to add the B+5 to the high gain channel or to the clean channel ?

[HotBluePlates]

would it be better to add the B+5 to the high gain channel or to the clean channel ?

Unless we're talking about a specific amp (with a schematic posted) I can't possibly say whether/where one should add a filter node.

It's like asking, "Should I add a 3rd axle to a vehicle?"

[shooter]

what he said^^


the "rule-of-thumb" i learn't somewhere, you don't want to feed more than 2 gain stages from the same PS point.


draw in your mind's eye, the resistors between each Tap, are now located directly below their current location, "breaking-up" ground instead of "breaking-up" +DC


As stated before, the current draw in a preamp is low, doesn't "strain" the DCv.  So your objective now, squash AC-coupling onto your signal path.