Tube plates glowing Red, amp keeps blowing fuses

[Enzo]

Half wave or full wave, doesn;t matter, other than ripple. Either way the same AC waveform is used. In both cases, the FIltered DC comes up to the peak voltage of the AC. Only difference is whether it recharges the cap 60 or 120 times a second. DC voltages are the same.

DC is thus 1.414 times RMS.

[Robert M. Martinelli]

Ok,
Just applied myself to a basic course in electronics, as it seems I've forgotten the basics - memory tricked me but I should have thought about it more thoroughly nonetheless, what memory can't do should be compensated by the capability of analysis.....If mine's gone, I'm possibly not good enough for this forum....

I beg your pardon, and ask you to believe no disregard whatsoever was intended.

My sincere apologies!

Best regards

Bob

[tubeswell]

Ah well memories come and memories go. Can't say I'm infalliable either :-)

[Robert M. Martinelli]

Hi TW,
It's true, memory can fail, but I should nonetheless have analyzed the whole thing better before posting.....seemed to me that, since only one diode was involved, the voltage was half the square root of two, but, as a matter of fact, thinking back to the wave-shapes out of a rectifier I can clearly see them in my mind now, and the rectified peak has the same amplitude of a full-wave rectifier, only the pulsating waveform is 50 or 60 Hz instead of 100-120 with a full wave rectifier, as Enzo remembered me.

Again, my apologies; ( I' m seriously thinking about quitting the forum 'cause I'm probably not up to the task if I make such mistakes ).

Best regards

Bob

[Enzo]

That's silly Bob, we want you here.

[Don Moose]

Ok, back to the actual topic -

If you have -50ish at the bias filter, then you need to look at the PI coupling caps and those 220k bias injection resistors.

The resistors are not passing enough current to overcome the leakage from the PI caps. Or the link from the bias filter to the bias injection resistors is toast?

Hope this helps!

[Robert M. Martinelli]

That's silly Bob, we want you here.

Thanks Enzo, I really appreciate it...

Let's do it this way....next time I' ll post I' ll make myself sure my brain is connected beforehand....

Best regards

Bob