EC8010 said:Just use a pentode with an undecoupled cathode resistor. If you make the control grid positive, you can use a larger cathode resistor, which is then multiplied by the pentode's enormous mu.
I just finished reading the triode/pentode CCS section in Morgan Jones book -- his description seemed a bit more involved....
dave
Probably striving for perfection then. Ain't needed. The same approach works fine in SS, biasing the "grid" (gate or base) positive (negative for P type) to account for the positive (on NPN and depletion-mode transistors) "grid"-"cathode" potential with a pair of diodes or (for really high quality) a zener.
Tim
Tim
I think Morgan Jones reffers on a CCS for a PSU.I need a CCS for anode load for a triode line stage.
Like Gary Pimm's CCS.But Gary Pimm has more information about SS CCS.I love tubes and I like a tubed CCS.But I need more information.
The new issue of audioXpress has a nice article!!A triode preamp with EL34 for CCS.
But any new information is acceptable!
Ray_moth:can you post a schematic?
Like Gary Pimm's CCS.But Gary Pimm has more information about SS CCS.I love tubes and I like a tubed CCS.But I need more information.
The new issue of audioXpress has a nice article!!A triode preamp with EL34 for CCS.
But any new information is acceptable!
Ray_moth:can you post a schematic?
Well, it is possible to use a pentode as an anode load, but it's not usually worth it - a high-mu triode is simpler and lower distortion. I'm guessing that Va is about 100V. Your best option is to turn the stage into a mu-follower using a 6C45 triode as the upper valve.
Attachments
may i ask, out of curiosity, why so much idle current? it would seem for most linestage type applications, you could get away with 10mA or even less depending on what your load looks like.
I agree with EC. I think a hi mu triode is practially as good a a pentode and easier to do.
In fact, if you were hanging around in 6922 territory, I think you could make a very respectable mu-follower with two 6922s.
I agree with EC. I think a hi mu triode is practially as good a a pentode and easier to do.
In fact, if you were hanging around in 6922 territory, I think you could make a very respectable mu-follower with two 6922s.
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