Posted by MQracing [ 151.197.124.169 ] on October 05, 2005 at 19:37:58:
In Reply to: Re: simplifying the Guinevere posted by manualblock on October 05, 2005 at 09:52:46:
Hello MB:
I'm not 100% sure I understand your question. let me give it a shot.
If your asking how difficult would it be to implement say a plate choke on top of the anode of the 5687... answer is (imo) simpler and moreso straightforward than the CCS. Just two wires to hook up. You would need to double check your voltage drop across the plate choke and make sure you get the target plate volts on the anode.
re: output impedances see Damir's response. What you would want to aim toward is a minimum of 100 henries imo.
all very doable and straightforward. Some folks (though not all) favor the sonics of choke loading the plate vis-a-vis a CCS. On paper the CCS is technically a better solution. It offers much, much higher AC impedance than a plate choke. So... it one of those subjective areas... try both and see which sounds better to you.
a high L choke can be substituted for the output resistor.... the claimed advantage here is that the choke offers relatively high AC impedance and less dc resistance than the resistor. Here you want to spec in a very large L for the AC choke. Say a thousand henries min.
Again... by the numbers alone the resistor offers a greater ac impedance (1 meg in this case)... but it also has 1 meg of dc resistance. A 1000 henry AC choke would have approx 125,000 ohms of impedance at 20 hertz... while only having say a thousand to four or five thousand ohms of dc resistance....
again, I think it's another of the instances of you've got to try it for yourself and "hear out" any differences and which sounds better.
all of my suggestions\ideas were offered only as alternate ideas\strategies. the guinevere looks pretty neat as drawn up and is even as drawn up still a doable, practical, rather straightforward line level amp.
cheers,
msl
[ Tubes Forum ] [ Help ]