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Big Bad Bob Big Bad Bob is offline
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Default Triode Naming Convention

On 2020-10-04 20:30, Phil Allison wrote:
This might inject up to 1mV into pin 2 if the grid source impedance were *10Mohms*. However, for a MM phono cartridge, the impedance is 1kohm at 50/60Hz and for a guitar PU about 10kokms.


Actually it's more like 100k for a typical guitar amp pre-amp input,


** The source impedance is what matters, and is as I stated.

Guitar PUs and phono PUs are both low value resistors at 50/60 Hz.


yeah, but a typical amplifier is going to have a 100k-220k in series
with the preamp input for dual jacks. And the volume control on the
guitar is 50k-100k. So you're right in saying that it has low impedence
at the guitar pickup [which has its own issues with inductive coupling
of hum, but that's a different issue] but the amplifier itself typically
has those series resistors so that you can have multiple guitars on the
same amp.

Given that, even if there's only a slight "barely detectable"
difference, if it's known, I'd just make the design leverage the one
with lower hum (alleged or otherwise) be the 1st stage amplifier.