5v333
Well-known member
in a triode transformer coupled output stage (pushpull in my case) - does the inductance of the transformer and the cathode bypass cap form a resonant component ?
im wndering because the lower frequencies in my tube amp are quite overwhelming and somewhat messy. when i probed one of the cathodes in the pushpull stage and sweep a sine wave , i have a resonance at about 6hz, quite wide aswell. i changed my bypass cap to 1000uF and it mght gotten a tad better but no biggy.
with about 17-20db global feedback, the lowend bandwitdth at the OT sec is about 6hz.
then i tried to short the cathodes so that the resistors went from saparate to shared, and now the resoance is more or less gone. totally different sound in the bass now. its clean and tidy, almost boring
im wndering because the lower frequencies in my tube amp are quite overwhelming and somewhat messy. when i probed one of the cathodes in the pushpull stage and sweep a sine wave , i have a resonance at about 6hz, quite wide aswell. i changed my bypass cap to 1000uF and it mght gotten a tad better but no biggy.
with about 17-20db global feedback, the lowend bandwitdth at the OT sec is about 6hz.
then i tried to short the cathodes so that the resistors went from saparate to shared, and now the resoance is more or less gone. totally different sound in the bass now. its clean and tidy, almost boring