Power cord for DSD Sr

@tedsmith Thanks! But I would assume though the stock cable is capable of dealing with those larger but short current draws?

I really don’t mind spending money on higher quality power cables. But utilizing the proper gauge I feel is important. Essentially, the right tool for the job.

For example, I have a Pass Labs XA30.5 and it comes with a boring looking but very robust 14awg power cord. I can’t fathom that a digital device like DS (even using the preamp) would ever draw more current than a Class-A power amp, and I also really doubt that Mr. Pass would provide an insufficient cable. So the 16 awg for the DS, at least in my mind, certainly seems sufficient. But to improve on that stock DS cable requires going to at least a 12 awg (AC3) or if you want the ‘best design’ the 8awg AC12! To me this just doesn’t make much sense…

@Paul Are you able to share why the decisions weren’t made to make an AC12 design available in a few different gauges?

It’s just a matter of degree - what tires are capable of supporting your car - what tires do you want on your car?

I’m not sure I agree with the tires analogy. As a driver, one can choose how much force is exerted on the tires, beyond the static weight of the sprung vehicle. Drive like my grandma or drive like Mario Andretti.

We don’t have the same choice with a nearly fixed current device like a preamp or DAC. Power amps, sure no question, but the DS? Isn’t the circuit in total always active except for the output transformers when in standby or mute?

I was just going to ask the same question that brett66 did above.
Does the dac draw a constant, fixed current? The DMP?

My point was simply that since things are a matter of degree you can choose your own point of diminishing returns.

Like I said above most linear power supplies take big gulps at the top of the AC waveform and nothing the rest of the AC cycle.

Think about sucking 10 x the nominal current for a short time - how much resistance does your power cord have at that instant? How much does that drop in voltage matter to your device? Use your ears.

With regard to power cord current carrying capability I was just answering a question about why the stock may not be good enough.

I don’t think this is the main issue with power cords for DACs, I addressed that a little above. (https://forum.psaudio.com/t/power-cord-for-dsd-sr/5445/14)

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Here’s a plot of the voltage and current of a typical low power audio device:


You can see the gulps of current at the peaks of the voltage. The ratio of max current to average current is about 10.

I have a dedicated circuit but it’s only 14awg. I’ve tried two commercially made power cables and two of my own making out of stranded 12awg copper THHN. Standard stuff. The only cable that seems to sound any different to me anywhere in my system is feeding my power regenerator and it makes a brassy, bright top end I don’t like at all. This cable is silver coated copper with fancy thick plated silver ends, all of the others are copper with either copper or brass terminations.

From a value perspective, I’ve just not yet realized anything close the cost in improvement. Perhaps my power regenerator is fixing most of what needs fixing.

I have 8 dedicated #10 (30A) circuits. Like I mentioned above power cords make a noticeable difference here. I have a small stable of them that I try on each new component. The dedicated circuits were one of the most cost effective things I did for my system.

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Garth Powell makes a compelling case for using a regen and high quality power cords.

On my PWD Mk 2 DAC I tried PS Audio AC-5, AC-10 and AC-12, a few days with each. I would have loved it if an AC-5 sounded the best or just as good. But I could hear differences that made me prefer the AC-12 to either of the others on the DAC and on any component I tried them on. So I struggled to and succeeded in installing AC-12 on all my components. The cumulative effect is real and I stopped my power cord search and experimentation then.

Ted, thank you for the circuit and illustrative graphs, very telling.

While I have known for a long time that equipment takes its power from the AC peaks, flat-topping the peaks, I do not understand why.

Is this primarily because power supply capacitors need only to partially recharge and their demand is not expressed until the voltage reaches an upper value?

I agree. I went from the 5 to the 12 and it took no effort to hear an improvement. It was substantially better, more so even than going from the stock cable to the 5. And the more articulate the amplifier, the more it matters. With my First Watt J2, the effect was a “holy crap” moment.

Sounds like I need to try some better cables that I have so far. Thanks for the very clear current sucking graph Ted.

Yep, the diodes keep the caps from unfilling back to the source so the caps supply current to the rest of the system when the input voltage is lower than the current cap voltage, only when the input voltage is greater than the cap voltage by the diode voltage drop do they fill back up. But they fill at the rate set by the capacitor’s impedance the transformer’s impedance, the power cord’s, the outlet’s, etc.

You can see that part pretty clearly with a simpler (but less efficient) circuit:


Thanks, Ted!

I was on the right track, but did not even think of diodes. This makes perfect sense.

Very cool stuff.

yoooreekah!!!

I read a story of a man, in Japan I believe, that managed to convince/pay the local utility to mount a dedicated transformer on the pole outside of his apartment.

How important are the power cords to each device if my single supply is 14awg? Everything DAC, pre, amps are supplied by it. Subs are on their own shared circuit.

To ask the inverse, would I be more likey to hear changes or improvements if I had a 10awg feeding into Propower 1050 online ups?

I don’t know ProPower, but in general, online UPSs are bad news for audio, even the ones that say that they have Pure Sine waves are almost always a bunch of little steps that stay within the 3% or whatever spec they have (or, with some, fewer great big steps.) I’m not saying ProPower did a bad job or a good job, I just don’t know. The problem with filtering those little steps to smooth them is that then you are adding even more impedance between the batteries and the output. Also, many online UPSs use SLA batteries and they have a maximum instantaneous output current that’s probably less than you want for spikes of current downstream.

Still I use an online UPS for my audio (and video) equipment that have switching power supplies since switching supplies are pretty insensitive to jagged input voltage and they draw current thru much more of each cycle than a linear power supply.

And don’t forget to check for the SPL of any fan, etc. in the UPS (often reported in dBa.) Online UPSs aren’t terribly efficient and generate about 1/4 to 1/2 as much heat as the rest of your system together. This often implies a need for more than passive cooling. (The ProPower 1050 specs “> 17dBa” (I think they have the comparison wrong or they are specing the minimum noise they make) if indeed it should be < 17dBa that isn’t bad.)

I thought I read you have a PurePower 1050. No? ProPower is the OEM. It draws about 100w at idle + audio system draw of 200w giver or take 10.

Unit is in a rack in another room, so I increased the pot to run the fans near full speed. They are < 17dBa and probably <30dBa in full speed mode, regardless, concrete insulated walls block it.

I have an electrician I’ve worked with for many years coming by to look at replacing my 14awg with 10awg plus another new run. Then I’ll try right to the wall. I didn’t pay much for the ProPower so no big loss if it does more harm than good. But I can swap power cables feeding it without shutting anything down. :wink:

Yep, as I said I use The PurePower 1050 for the things in my system with switching power supplies. It’s been serving me well for over a decade. It is darned quiet.