Posted by PakProtector [ 152.163.100.134 ] on March 24, 2006 at 12:37:27:
In Reply to: Re: Anyone use 6S45P with 12B4A concertina for PP 7591A or 6L6? posted by Scholl on March 24, 2006 at 11:31:10:
Hey Scott,
Looking forward to seeing you at the Mill...I am going to bring all-tube active loaded 12B4 linestage. I have heard good things about the one you built for Jonathan, and I look forward to hearing it.
Thanks for the insight on the 6C19. I am considering a few uses for the tube, among them as the lower part of a hybrid cascode. When hunting maximum swing from a given B+, a low plate Z triode is just what the Doctor ordered. The ability to set the upper grid line of the faux pentode circuit *ANYWHERE* by moving the MOSFET's gate voltage is a very useful property. It keeps the load line out of the sub-Ec2 knee very well.
The additional demands of the E-Linear circuit on the drivers stage set-up require a very flexible front end. See Merlin v2 in the projects folder. Or the buffer linestage...it is all sorts of handy.
That these 6C19's are available for less than $1 each delivered and can stand the idle current a 10k plate load offers with a 500V B+ can deliver is another 'Plus'. A proper radiator for the MOSFET is not as easy.
I have seen the plate curves from the Klausmobile site, and find that they look at least as linear as a 12B4. The 500R plate R when resistively loaded for 6-7 dB of gain is quite good too. Forget the need for a second buffer stage. 5k and 300V and you're 'Off to the Races'...:)
cheers,
Douglas
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