[Arny Krueger]

"Eeyore" wrote in
message
Iain Churches wrote:

But then SET amps traditionally
have little or no NFB and so are inherently stable

An absence of NFB **DOES NOT** make any ampliifer
'inherently stable'. Such an idea is pure horse manure.

Yep, in fact NFB that is truely NFB never causes instability. Instability
only comes when a loop that is NFB in the mid band becomes positive feedback
due to phase shift, usually at the frequency extremes.