December 6th 07, 12:36 AM
posted to rec.audio.tubes,uk.rec.audio
|
|
|
Plate characteristics at low anode currents in triode mode
"Ian Thompson-Bell" wrote in message
...
Doug Bannard wrote:
"Ian Thompson-Bell" wrote in message
...
I have being playing around with plate characteristics graphs, looking
at how basic parameters (gm,rp and mu) vary with operating point. The
most frustrating thing about this is that the published curves all
extend to rather large plate currents and voltages. For my preamp I am
working at plate currents of less than 5mA and the curves here are
rather cramped. Is there any source of curves that are expanded for the
lower plate current region?
Cheers
Ian
Hi Ian:
If you give me the range of plate currents and voltages, I can plot you a
set of curves on my tracer and email you a digital camera photo of same.
For example, if you tell me that the maximum y-axis current you want is
5mA and the x-axis voltage (Vak) is to be 300 volts, I can plot you a set
of 11 curves, including Vgk=0V. I can set the grid volts per step to
anything you'd like within reason.
Just let me know the values you want and I'll give it a try. Please also
let me know:
1) Do you want the screen grid connected through 100 ohms (or other
value) to the plate, or just a direct connection?
2) I can connect the suppressor grid anywhere you want. Either to the
plate or to cathode are the obvious choices. Where would you like it or
do you want curves for both connections?
All the best : Doug Bannard, P.Eng. )
Thanks Doug, that is a really kind offer. I am mainly interested in plate
currents up to 5mA and plate volts up to 250V. I am considering two
alternative triode connections of the 6AU6.
1. G3 and G2 tied to plate (no series resistors)
2. G3 and plate tied to ground with G2 used as a plate.
Curves for both configurations would be nice.
Many Thanks
Ian
Ian:
Please send me your email address to . When I tried your
ruffrecords email address, it didn't work for me.
All the best : Doug
|