How true, LOLAll that for about 120mA per rail, but it's so worth it to hear all that groove noise,
How true, LOLAll that for about 120mA per rail, but it's so worth it to hear all that groove noise,
Nice one, but honestly , wouldn't it have been easier, to replace all that regulation with a bank of LiPo's and a simple SMPS charger?It is a MC stage but it has enough input voltage headroom that one can use HO MC carts up to around 1.5mV.
Because its not just one opamp and a 3 pin reg...
There's 108 transistors in a stereo build and a fair bit of class A psu.
OK I'll bite...Mostly positive responses but not many. Nobody tried to argue with my assertion about the mains cable being an unimportant component![]()
Monoprice caries some heavy duty power cords, 14AWG, 15A/1875W, 3-Prong, Black, 6ft for $5.99.So the bottom line here is unless you're running a larger tube amplifier or a very large class A solid state amp, the power cord will probably not be an influence. But if it is, if you run that kind of equipment and found that a power cord does make a difference, you may be disappointed to learn that you can get materials at Menard's (heavy power cord used for stoves or clothes dryers) and with some nice looking connectors off of Amazon you can make a power cord that will work just as well and for under $100 including shipping. ...
To start with, I am a fan of Atma-Sphere, you guys make very interesting amps, I have been tempted to get one.For most solid state amps it probably isn't. But for tube amps (or larger class A solid state amps) a power cord can be a deal due to voltage drops. I've seen a power cord gobble up significant power, causing the amp to lose 40 Watts of power at its output (about 30% of total output power). The voltage drop across the cord was something just north of 2 Volts. Not surprisingly the power cord was warm to the touch not just at the connectors but along its length. Its a series resistance after all and Ohm's Law still applies.
Again, 20 amps is in 12V or 6V rail, on a 110V mains input it translates to 2A or 1A ! and a cable of 1 ohm resistance, it means 2V drop max? again significant?In a tube amp you can have a significant filament circuit. The one in the example just above had a 20 Amp filament circuit- it had a lot of power tubes. In addition its output section was composed of triodes which are more sensitive to B+ than pentodes. So the result was the filaments cooling off a bit in tandem with there being less B+ available, which is dropped across the now cooler power tube.
This is where you lose me completely!If the power cord has lousy high frequency bandwidth you might get some current limiting on the peaks of the 'sine' wave since that is the only time filter caps charge; this could lead to the power supply being a bit low. But I see that as a minor issue, if there is one at all.
108 transistors? Whew. Why on earth, for such a straightforward application? I smell overdesign here.It is a MC stage but it has enough input voltage headroom that one can use HO MC carts up to around 1.5mV.
Because its not just one opamp and a 3 pin reg...
There's 108 transistors in a stereo build and a fair bit of class A psu.
If the filament in a tube runs at a lower voltage, the tube will have less emissions. So you can see how this will lead to lower power in tandem with lower B+.To start with, I am a fan of Atma-Sphere, you guys make very interesting amps, I have been tempted to get one.
A 2V drop on the power cord is insignificant to normal voltage dropouts that can occur for reasons beyond our control. In UK (240V) I have monitored voltages as low as 230V and as high as 245V. Does that affect some amps to the tone of 40%?? I find that hard to believe.
If a small voltage drop causes so much problem, shouldn't a reputable manufacturer account for that, or at least use a chunky power cord, bolted to internal terminals, therefore not be replaceable?
Again, 20 amps is in 12V or 6V rail, on a 110V mains input it translates to 2A or 1A ! and a cable of 1 ohm resistance, it means 2V drop max? again significant?
This is where you lose me completely!
High frequency bandwidth? on a power cord? The only frequency I wish to pass through my power cords is 50/60Hz and nothing beyond - Indeed, I use elaborate L-C networks to make sure. Any high frequency through a power cord is RF noise!
Ever seen what makes up a square wave? With each succeeding harmonic the leading edge gets steeper. You need bandwidth in order to pass that. Fortunately this really isn't an issue with most power cords. That is why I mentioned that you can get decent materials to build a good power cord at Menard's.Are you implying that a BW of 1kHz is not enough for a power cord and that there are mains cables that cannot even reach 1kHz BW ?
All frequencies above 1kHz do not contribute to the reservoir caps charging.
Below measured current spectrum in the rectifier path (24A peak)
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IME most of the resistance is actually at the cable terminations; the connectors heat up before the cordage does. And yes that takes some current. Big class A power amps draw lots of current.Power chords have impedance in the miliohm range, that would have to be some serious current draw to cause a 2v drop.
Yep, seen plenty and in no way the current draw from any mains supply (is does not matter which diodes are used in the rectifier) looks anything like a square-wave.Ever seen what makes up a square wave? With each succeeding harmonic the leading edge gets steeper. You need bandwidth in order to pass that. Fortunately this really isn't an issue with most power cords.
It looks to me as if you missed my point. I'm not talking about a square wave. Filter caps can only charge when their voltage is lower than that of the output of the rectifiers; the rectifiers can only turn on when the power transformer voltage is higher than that of the filter caps. That will be at the peak of the AC waveform. At this time the rectifiers commutate; current flows with a very steep leading and falling edge. This has nothing to do with harmonics of the AC waveform as it does simply switching from off to on (commutation). The current flow will have a lot to do with how depleted the filter caps got between peaks of the AC waveform. All this was covered in opening posts of this thread.Yep, seen plenty and in no way the current draw from any mains supply (is does not matter which diodes are used in the rectifier) looks anything like a square-wave.
This has nothing to do with harmonics of the AC waveform
And again, as you mentioned earlier, a chord bolted to internal posts, negates the termination resistance (almost!), and as I mentioned earlier a chunky cable, with factory plug and bolted to the inside terminals, should give ideal arrangement for high current situations, probably why we see them in fridges, washing machines, and we should see them on high current amplifiers!-And there you go. As I mentioned earlier this is a minor influence; most AC cords have plenty of bandwidth to handle this issue.