I'm building a new amp which I want to use EL34s or 6L6s.
What is the best negative voltage to work from before the voltage divider for each
Cheers
Bias Circuit
Moderators: pompeiisneaks, Colossal
-
- Posts: 476
- Joined: Tue Sep 10, 2019 7:46 pm
Re: Bias Circuit
EDIT: didn't understand what you were asking at first. -50v ish should be sufficient
got a transformer already or one in mind? if you've got a bias tap work from that. if not then you're stuck working from the ht winding. how are you developing the ht voltage? full wave rectifier? Diode with the cathode towards the transformer should be good enough. if it's a bridge then you've got some experimenting to do
really i just copy from other schematics that use a similar transformer
got a transformer already or one in mind? if you've got a bias tap work from that. if not then you're stuck working from the ht winding. how are you developing the ht voltage? full wave rectifier? Diode with the cathode towards the transformer should be good enough. if it's a bridge then you've got some experimenting to do
really i just copy from other schematics that use a similar transformer
PRR wrote: Plotting loadlines is only for the truly desperate, or terminally bored.
Re: Bias Circuit
More info essential! Need to know what your expected / intended screen grid voltage, and plate/cathode current, at idle is.populartsl wrote: ↑Sun Aug 30, 2020 1:19 pm I'm building a new amp which I want to use EL34s or 6L6s.
What is the best negative voltage to work from before the voltage divider for each
Cheers
Then just look at the triode connected plate characteristic chart and see what control grid voltage is required to achieve that plate voltage and current; then increase it by 10-20% to account for use of non bogey tubes. Hey presto, that's the most bias voltage you'll probably require.
eg see p3 of https://tubedata.altanatubes.com.br/she ... /6L6GC.pdf and p8 of https://tubedata.altanatubes.com.br/she ... e/EL34.pdf
My band:- http://www.youtube.com/user/RedwingBand