That's the point to this thread. I believe there is no simple answer, because it depends on a) the capacity, the rating of the transformer(s), b) the size and quality of the capacitor bank, and c) the PSRR of the amp, for both positive and negative rails, just for starters.If what we are attempting to do is keep the voltage on the +/- rails from dropping or sagging as you say, is there an ultimate value for this. If we just increase the power capacitor value to some excess value then the slew rate becomes important and we have a problem with charging the capacitor bank fast enough.? If to small a capacitor rating the voltage drops. What are we matching the expected output of the amp plus and loss to heat in the output devices?
Also, do we want the amp to withstand heavy duty testing by a reviewer, just to be able to claim to be the next Krell, or merely to handle the demands of normal music content.
Frank
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I didnt say that since Stasis was also home build.Right, we're getting there. You like most valve amps, a few old SS ones, and assume anyone who builds stuff for themselves hasn't a clue what they're doing.
Why are you continuing to bring this back into the discussion?.............. It even doesn't needs a capacitor multiplier, nor smps.
If you have new information on these that needs discussion that would be relevant to the topic then discuss, else leave it alone.
Power supply sag cant be a problem in a good design. One designes an amp with a certain power supply voltage. Then the power supply must be designed to deliver that voltage at mayimum current. Thats all, the voltage will be higher when the current draw is lower but thats not a problem.
Power= U^2/R or I^2.R so its all the same.I don't know about you, but speaking for one of the ECX10N20's I have here: "Mmmm I like current, and when I want it.. I want it.. NOW!".
I dun know these transformers. What is CLC? How heavy are they?I have a couple of original late '80s bought Partridge output transformers looking at me, they're saying they'd like a CLC to feed them.
No.Power= U^2/R or I^2.R so its all the same.
It's not the same, as he stated.
you are looking at resistance as the sole load and ignoring all parasitics.
You are wrong on at least two counts.
The load is not pure resistance.
The supply is riddled with parasitics.
No.
It's not the same, as he stated.
you are looking at resistance as the sole load and ignoring all parasitics.
You are wrong on at least two counts.
The load is not pure resistance.
The supply is riddled with parasitics.
Thank you Andrew.
I have a feeling that liching1952 just feels like arguing for the sake of it.
I dun know these transformers.
Partridge was a British transformer company.
They weigh a standard bag of potatoes each, go by the name TH4663, afaig there are still a couple of shops that sell them to silly buggers for $1000.
(but if weight is your thing, how about 30lb each Partridge really high current chokes i wrenched out of pro-medical jogg/walking machines ?)
Basic physics says, only the resistive part of the load absorbs power, the imaginary part doesnt.No.
It's not the same, as he stated.
you are looking at resistance as the sole load and ignoring all parasitics.
You are wrong on at least two counts.
The load is not pure resistance.
The supply is riddled with parasitics.
I'm not certain that is true. If you increase the quiescent supply rail voltage enough, it doesn't matter how much it droops (assuming PSRR is not an issue) so you can have a small cap. Your stored energy will increase because of the higher voltage. What you can do is calculate the smallest cap required, given a stated Vdc (exceeding Vpk by whatever margin you deem helpful). You can also calculate the minimum stored energy (see my earlier post) but that merely lets you then choose C (given Vdc) or choose Vdc (given C).gootee said:Similarly, for any power amplifier with a linear PSU there is a lowest reservoir capacitance, below which the amplifier will not meet its specifications. How can we calculate the value of that capacitance?
I suspect you are all looking for the gold at the end of the rainbow: there is not an optimum value for C or Vdc, although there may be an optimum combination. Total 'AC in' to 'sound out' efficiency may be a useful parameter, as raising Vdc unnecessarily reduces efficiency.
Weight more or less gives an indication how they will perform at the lower end. If they are good, so build a good amp with KT100 or so. And what do you mean CLC. AndrewT wrote that it is a circuit smoothing thd power. Does it has anti hum windings for this purpose?Partridge was a British transformer company.
They weigh a standard bag of potatoes each, go by the name TH4663, afaig there are still a couple of shops that sell them to silly buggers for $1000.
(but if weight is your thing, how about 30lb each Partridge really high current chokes i wrenched out of pro-medical jogg/walking machines ?)
Yes am MSc but doesnt understand power factor correction so explain.I also suppose that you have never heard of power factor correction, specifically to counter this problem.
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