Let's say I were to put a switch into a BA-2 to allow switching between "local" (LTP + VAS) and global feedback (including the OS).
The phase lead capacitor is 20pF. The local feedback trace is short, so no big deal.
But the wire for the global feedback has to come from the output boards, and in a monoblock implementation that means from both sides of the case. So they're each 8" long or there-abouts, and we're talking 100s of nH. Is that going to swamp the phase lead capacitor?
(Pretend I don't really understand how capacitance and inductance in series work, because that would be correct. But it seems like they're at cross purposes.)
The phase lead capacitor is 20pF. The local feedback trace is short, so no big deal.
But the wire for the global feedback has to come from the output boards, and in a monoblock implementation that means from both sides of the case. So they're each 8" long or there-abouts, and we're talking 100s of nH. Is that going to swamp the phase lead capacitor?
(Pretend I don't really understand how capacitance and inductance in series work, because that would be correct. But it seems like they're at cross purposes.)
use trick from Tube Yore - route NFB with coax cable , grounded on both sides , or just upstream side
then choose lag cap with scope help
then choose lag cap with scope help
no need
use shiniest and brightest and most Peasant color LED you can find ....
and yes - biggest
use shiniest and brightest and most Peasant color LED you can find ....
and yes - biggest
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