I can't find any data sheets describing a #19 in class A operation. Only in class B.
I want to use one as a phase inverter. Anyone know what the bias point should be? Or, can I operate it in "zero bias" mode? Now that would make things easier.... is that asking for trouble?
I've seen a 6N7, another class B amp, used in a similar way.
I want to use one as a phase inverter. Anyone know what the bias point should be? Or, can I operate it in "zero bias" mode? Now that would make things easier.... is that asking for trouble?
I've seen a 6N7, another class B amp, used in a similar way.
After taking a quick look at the curves, in the RCA manual, it will be possible to bias it in a normal class A point, say at -3V grid, 140V anode and ~2,5mA of plate current... giving a very approximate mu=25, gm=1mA/V and rp=25k... (just rough calculations)
But, if you then take a look at the -6 grid line, you can see that this tube will be very non-linear in this region of its curves.
As fdegrove say; Its made for class B operation.
Though the grid current at Zero-bias will be minimal, as soon as any signal starts to swing the grid, the grid-current will be a problem.
But with that said, I've got a plan to play with the #19 some day. I'm thinking of trying to make a PP class A2 headphone amplifier of it! Some day...
Bad news if you already have the tubes; Don't use them as phasesplitters.
Stigla
But, if you then take a look at the -6 grid line, you can see that this tube will be very non-linear in this region of its curves.
As fdegrove say; Its made for class B operation.
Though the grid current at Zero-bias will be minimal, as soon as any signal starts to swing the grid, the grid-current will be a problem.
But with that said, I've got a plan to play with the #19 some day. I'm thinking of trying to make a PP class A2 headphone amplifier of it! Some day...
Bad news if you already have the tubes; Don't use them as phasesplitters.
Stigla
WAAROM ZIJN DE BANANEN KROM?
John,
Tubes are designed for a certain class of operation.
This one has absolutely ugly looking curves.
They wanted the higher mu and messed up the linearity in the process.
They do that by changing the spacing between elements and a dozen other parameters.
Surely you don't use those big Class D devices for audio either?
At least most of them have not been designed for that kind of service.
Full moon maybe?
Ciao,
John,
Tubes are designed for a certain class of operation.
This one has absolutely ugly looking curves.
They wanted the higher mu and messed up the linearity in the process.
They do that by changing the spacing between elements and a dozen other parameters.
Surely you don't use those big Class D devices for audio either?
At least most of them have not been designed for that kind of service.
Full moon maybe?
Ciao,
Yes the full moon occurs here tonight too. But probably a few 10's of minutes different in time to you.
Yes, I'm aware of the inter-electrode spacing effects, and grid pitch. But I have always been open minded about class and application. After all, some of the best respected devices we use for audio, were not intended for audio at all!
Class D:
Never heard of it being done with valves / tubes.
Done a fair bit of class C in my time. Capacitance and dissapation were the only issues I can think of.
Yes, I'm aware of the inter-electrode spacing effects, and grid pitch. But I have always been open minded about class and application. After all, some of the best respected devices we use for audio, were not intended for audio at all!
Class D:
Never heard of it being done with valves / tubes.
Done a fair bit of class C in my time. Capacitance and dissapation were the only issues I can think of.
Low filament current?
Robert, I think you better go check your facts - the 5 volters are only 50mA less current than "modern" 6.3 volt tubes, and the older versions of many battery tubes drew 1/2 an amp each!
Not to mention that in my experiments, they've never sounded compressed to me. What circuit were you using or listening to?
Robert, I think you better go check your facts - the 5 volters are only 50mA less current than "modern" 6.3 volt tubes, and the older versions of many battery tubes drew 1/2 an amp each!
Not to mention that in my experiments, they've never sounded compressed to me. What circuit were you using or listening to?
OK sorry maybe i should say low wattage. 2volts @ .25 amps is a small electron cloud in my book.Joel said:Low filament current?
Robert, I think you better go check your facts - the 5 volters are only 50mA less current than "modern" 6.3 volt tubes, and the older versions of many battery tubes drew 1/2 an amp each!
Not to mention that in my experiments, they've never sounded compressed to me. What circuit were you using or listening to?
Robert M.
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