Well, I got the power supply hooked up. I used motor run oil caps and a big old choke that I don't have specs on. I learned alot, but have one small problem. Instead of 430v I ended up with 570
This is without the .13 load, but I'm not expecting much sag out of this monster tranny. I'm going to put together a load (any suggestions on how) and see what I get. I've got it all built on a chassis so I may be looking for some other tube (schematic) that can handle this voltage and will like the 10kohm primary OPT's. Maybe 807's? I don't know if it is feasable to try and drop B+ 120 to 140 volts. I do have another choke.
This is without the .13 load, but I'm not expecting much sag out of this monster tranny. I'm going to put together a load (any suggestions on how) and see what I get. I've got it all built on a chassis so I may be looking for some other tube (schematic) that can handle this voltage and will like the 10kohm primary OPT's. Maybe 807's? I don't know if it is feasable to try and drop B+ 120 to 140 volts. I do have another choke.You could look at a choke input filter. This will drop your voltage. It may be a little less predictable to design, sim if possible to check for ringing.
If you want to produce a dummy load, divide your desired B+ by your desired current draw for a stage and this gives you a resistance value to use. Apply it to your supply to see whether it drags it down to where you wanted it to be.
Also, multiply the voltage by the current to see what power the resistor will be dissipating.
If you want to produce a dummy load, divide your desired B+ by your desired current draw for a stage and this gives you a resistance value to use. Apply it to your supply to see whether it drags it down to where you wanted it to be.
Also, multiply the voltage by the current to see what power the resistor will be dissipating.
Umm <lndm picks up jaw from floor>, thats a large resistor.
Options:
1. Put a couple of 10W resistors in series and only turn on long enough to take measurements.
2. Use a circuit simulator, I like this method.
3. Make use of the fact that valves are resilient. Make best estimates on values, build your circuit, double check it, and switch on. I mean, if you have a large supply voltage, using that to calculate a dropping resistance for the supply (voltage to drop / current), and using the factory spec cathode resistance, you'll probably end up with less than the expected voltage on your devices anyway. Set your multimeter on a critical point in your circuit before turn on and watch it. You might chose the cathode resistor, so you can watch the current, or measure the anode voltage. If for some reason the voltage gets too high, just switch off.
Killing voltage with series resistance can work for a single ended circuit, but class AB draws a range of current and makes the choke input look like a better idea.
I also have 130V to kill. I use some series resistance to protect my rectifier from excess capacitance, I use some series resistance to reduce ripple, I use a choke that has series resistance. I have enough capacitance at the end to make it all good.
BTW, those are nice looking caps
Options:
1. Put a couple of 10W resistors in series and only turn on long enough to take measurements.
2. Use a circuit simulator, I like this method.
3. Make use of the fact that valves are resilient. Make best estimates on values, build your circuit, double check it, and switch on. I mean, if you have a large supply voltage, using that to calculate a dropping resistance for the supply (voltage to drop / current), and using the factory spec cathode resistance, you'll probably end up with less than the expected voltage on your devices anyway. Set your multimeter on a critical point in your circuit before turn on and watch it. You might chose the cathode resistor, so you can watch the current, or measure the anode voltage. If for some reason the voltage gets too high, just switch off.
Killing voltage with series resistance can work for a single ended circuit, but class AB draws a range of current and makes the choke input look like a better idea.
I also have 130V to kill. I use some series resistance to protect my rectifier from excess capacitance, I use some series resistance to reduce ripple, I use a choke that has series resistance. I have enough capacitance at the end to make it all good.
BTW, those are nice looking caps
They do seem to be nice caps. I have a supplier at work who sells to me at cost if stuff is for my use. I got them for 6 bucks each. I'm going to do a little experimenting with some dummy loads and see if I have any sag at all on this contraption. The down side to all this is I have to do all the laundry now as my wife refuses to come down into the basement. Oh well. Thanks for the ideas, Jay
lndm said:
I misunderstood. The circuit I'm using wants 430v@.13A. I built this light bulb thing to simulate that load. Five 15 watt bulbs. It brought the vdc down to 515 from 582. Now I will try to figure out a resistor value (to put in series with the load?). Thanks, Jay
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Hey, I'm just moving along fast (for me) and I'm hoping someone will stop me before the mushroom cloud appears. I don't know though, TV sounds better than pipefitting. We could call it Science with a middle aged bald guy! I don't know, maybe radio, what do you think?
I don't know, maybe radio, what do you think?Attachments
lndm said:Umm <lndm picks up jaw from floor>, thats a large resistor.
Options:
1. Put a couple of 10W resistors in series and only turn on long enough to take measurements.
2. Use a circuit simulator, I like this method.
3. Make use of the fact that valves are resilient. Make best estimates on values, build your circuit, double check it, and switch on. I mean, if you have a large supply voltage, using that to calculate a dropping resistance for the supply (voltage to drop / current), and using the factory spec cathode resistance, you'll probably end up with less than the expected voltage on your devices anyway. Set your multimeter on a critical point in your circuit before turn on and watch it. You might chose the cathode resistor, so you can watch the current, or measure the anode voltage. If for some reason the voltage gets too high, just switch off.
Killing voltage with series resistance can work for a single ended circuit, but class AB draws a range of current and makes the choke input look like a better idea.
I also have 130V to kill. I use some series resistance to protect my rectifier from excess capacitance, I use some series resistance to reduce ripple, I use a choke that has series resistance. I have enough capacitance at the end to make it all good.
BTW, those are nice looking caps
Ok, I understand what you are saying now. With everything switched to choke input I dropped a bunch to 350v with a load of 140mA. The circuit I want to use is~ 130mA. I downloaded PSUII @ Duncan and as soon as I figure out how to use it I will try some different things. Thanks for your patience, Jay
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