Power Section Choke on Chiefton

[Ed_Chambley]

Attached here is the power section of a Matchless Chieftain.  It looks different from others I have seen and I do not understand the choke and why it is used the way it is.  I am building a power section for 2 EL34's and ran across this.  It looks as the choke is filtering the plates as well as the screens.  There are very large resistors as well.  What is the reason/benefit of such.

[sluckey]

Matchless is fond of using parallel B+ nodes after the choke. Look close. The choke is not filtering the PA plates.

By using parallel nodes, one and only one resistor is used to determine the B+ for any node. And the node B+ voltage is totally independant of any other node. That's not the case with the more familiar series B+ nodes.

[12AX7]

I noticed that about the chieftain too long ago when i built my first amp and used the chieftain as a model for the cathode bias output. But i never figured out why they use parallel nodes like that. All i could figure is maybe the wanted more voltage than a series rail would allow. Maybe one stage needed to be too low to allow the later stages enough voltage? Any idea as to why?

[Ed_Chambley]

Yes, it is not filtering the plates.  I see.  What is the need for such a large choke?  20H and 160ma and is it necessary.  I like the separate resistors and caps for each tube cathode.  I actually have the parts and plan to use this for power section.  Looking at Mullards Datasheet on EL34's running at 375 v cathode Rk is 260 ohm per tube.  Why the large wattage resistors?