Should be about 15dB with the switch shut and maybe 2-3dB more with the switch open.Got it. What level of gain are you expecting?
Well, we need enough voltage to ignite the regulator tube, and higher impedance between B+ and regulated B+ will increase power supply ripple rejection.I'm late to the party, but I don't understand why you're using a relatively high voltage power supply and then burning off most of the power as heat in that last 4.7K resistor.
What happens if line voltage is a little low? Even at 180V you are below the minimum power supply voltage to get an 0D3 to strike, so it's entirely possible that you could build that and it simply wouldn't work. It would also be a bit noisier.Using the same transformer that you already have, I'd using half of the secondary, i..e 125v instead of 250v and then change R2 from 4.7K to roughly 560ohms. Instead of dropping from 330v to 150v, you'll drop from 180v to 150v.
I do agree that the 269AX will be marginal with a tube rectifier but probably would be fine with solid state rectification.Well, we need enough voltage to ignite the regulator tube, and higher impedance between B+ and regulated B+ will increase power supply ripple rejection.
What happens if line voltage is a little low? Even at 180V you are below the minimum power supply voltage to get an 0D3 to strike, so it's entirely possible that you could build that and it simply wouldn't work. It would also be a bit noisier.
I find the power to be far less problematic than overly tight compliance. I have done designs like this where the compliance is pretty tight, and it's a big letdown when you fire things up and the 0D3 never ignites. Once you've done that and had to start over with a power transformer providing higher voltage, the extra dissipation doesn't seem like that big of a deal.It still offends my sensibilities to burn that much power in a dropping resistor, so if it were me I'd find a more appropriate power transformer and minimize that last resistor so it doesn't generate so much heat.
PSPICE.I'm ordering the last few things to bread board. What can I use to simulate the load on the PS circuit? I want to test every thing including the glow-tubes but not the entire circuit.
I thought a 4.7K/20W resistor would be easy to find. Instead, you could just use a pair of paralleled 10K/10W resistors and that should work.I think I need a 4.7k resistor of ? wattage. Correct?
I'm not sure what you're asking here...I know I can just run it but I want to test it under load. I do have a speaker load box I made with 8 & 16 ohm taps