Please help with cathode values for driver board circuit.

[offabit2001]

Hi everyone, was going to etch a driver board for a project amp. I going to be using the Poseidon board layout for the Dynaco Mark III designed by Shannon Parks. The part of the design I'm not thrilled about using is the LM334. This is the description: "The LM334 is a 3-terminal adjustable current sources featuring 10,000:1 range in operating current, excellent current regulation and a wide dynamic voltage range of 1V to 40V. Current is established with one external resistor and no other parts are required." I want to eliminate the LM334 and use a cap and resistor to ground. Can anybody please suggest some values I can try that won't effect the integrity of the circuit e.i. sound quality. Thanks very much in advance. Here is the schematic below.

[2deaf]

Won't work.  The outputs of the splitter are very balanced with a constant current source, but extremely unbalanced if you replace the constant current source with a resistor. 

[2deaf]

The attached drawing shows an ideal version of the Mark III phase splitter.  The constant current source holds the current constant, but allows the voltage to vary. A 1.0Vac signal is applied to the Stage 1 grid and the positive phase results in an increased current through Stage 1 as shown.  Because there is a constant current supplied to the tied cathodes, Stage 2 must have an equal decrease in current.  The equal but opposite current changes are across plate resistors of the same resistance, so the outputs will be equal but opposite.

These are ideal conditions, so an increase in grid-to-cathode voltage of the same magnitude as a decrease in grid-to-cathode voltage will result in current changes of equal magnitude through the tube, although the changes will be opposite.  If the voltage on the tied cathodes is one-half the difference between the grid voltages, Stage 1 will have an equal but opposite grid-to-cathode voltage change compared to stage 2.
 

[shooter]

the lm334 has always been quite reliable n stable in apps I've used; temp monitoring, temp controlled squirrel cage motor controller, even upgraded a mercury bulb thermostat with one

[PRR]

This will work. The '334 will work better.