Global NFB only has an effect if it wraps around some gain.
A split load PI has a gain below 1 and the power stage gain is just above 1.
So apart from the DC/loading problem, the NFB won't make a difference.
The circuit shown in post 14 takes care of that by an added gain stage.
Another example with a split load after a gain stage would the 80s Fender Super Champ, but there are many others.
In fact, any tube power amp with a split load PI and global NFB needs to have an extra gain stage.
A split load PI has a gain below 1 and the power stage gain is just above 1.
So apart from the DC/loading problem, the NFB won't make a difference.
The circuit shown in post 14 takes care of that by an added gain stage.
Another example with a split load after a gain stage would the 80s Fender Super Champ, but there are many others.
In fact, any tube power amp with a split load PI and global NFB needs to have an extra gain stage.
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