Originally Posted by bbmiller
How pure does heater current and voltage have to be? Pictured below are two pictures from this and another thread showing what I think are linear regulators attached to two different types of 12V DC power supplies one being a laptop and the other being the 12 all rail of a PC power supply. In both pictures the 12V is sent to what the responders called a regulator, but I believe may be a linear regulator to be more precise about it. I thought linear regulators have to waste away a little voltage so if you were to put linear regulators on 12 V to regulate 12 V they would not work. Am I making correct assumptions?
Also I believe I do see slight stroboscopic effects from incandescent light bulbs which aren't strobe lights. I believe this is due to slight fluctuations in the light due to slight cooling between AC cycles with the voltage goes to zero between sine waves. But if we are talking about even slider fluctuations less than 100% pure DC power supply could that affect our audio if used for heater current and not for cathode or anode voltage?
So in summary is slightly DC impure heater current nonetheless as pure as we will ever need because it is heater current and not cathode or anode voltage and current? And if we do need pure regulated DC from a linear regulator do we have to start out with more than 12V to get a voltage regulated to 12V ?
I don't think the voltage has to be all that pure just to run heaters. Collectively, we are successfully using battery chargers, laptop power supplies, virtually anything that can provide adequate voltage and amperage. The cheap regulators we are using allow us to adjust the voltage as our power suppliers might be putting out 30 volts, 24 volts, 15 volts, or whatever. And yes, the regulators do "waste" a little voltage, so if you want to run 12.6 volt tubes, you will need a power supply that can output around 15 volts, or higher.
For drivers, I recommend a 30 volt power supply as this will allow the use of 6.3, 8.4, 12.6, 20 and 25 volt tubes. In order to run 6SN7's as drivers, you will need about 5 watts (6.3V x .6A = 3.78W). If you want to run 6AS7's as drivers, you will need at around 20 watts (6.3V x 2.5A = 15.75W). For power tubes, specifically 6AS7's, which run at 6.3 volts / 2.5 amps, you will need a power supply that can handle both tubes, around 40 watts (6.3V x 5.0A = 31.5W).
Regarding voltage regulators, the limiting factor is usually amperage. Most of what you see on eBay are limited to about 2 amps. These are fine for the vast majority of driver tubes. But if you want to run 6AS7's as drivers, you need a regulator that can comfortably handle 2.5 amps. An inexpensive 5 amp regulator, like the one I have, works well. If you want to run a pair of 6AS7's as power tubes, you will need a regulator that can comfortably handle 5 amps. I personally do not trust my cheap 5 amp regulator to actually handle 5 amps, so if I wanted to run 6AS7's as power tubes, I would purchase one of the cheap 8 amp units, similar to the one that Hypnos1 uses.