[Help-gnucap] Convergence failure with BC547C

[Karel Kulhavý]

Hello

I am trying to simulate a differential 2-transistor stage with BC547C.
With rstray, it fails to converge in one cycle (on second edge, the edges
are always difficult)
With norstray, it goes through all 8 cycles programmed.

ngspice doesn't seem to have problems with BC547C because AFAIK it doesn't
have any rstray feature.

Is it possible to enhance somehow the convergence so I can make it converge
even with rstray? Tinker with some convergence options? Which options are
relevant in this case?

Does it mean that the circuit will oscillate due to parasitic feedback caused
by stray circuit elements? Is convergence failure and tendency to oscillate
tightly coupled?

Thanks in advance for advice,

Cl<