Which power cord should you buy first

I realize this is an old topic.  It's good getting current experience.   Appreciate everyone's input .  My Pass labs 350.8 amp comes with a pretty beefy power cord with its own direct power line.  I have a separate Lumin U2 streamer and La scala DAC.  Sounds like experimentation is in order between these.  Thanks again 

@salc trying is the only way to find out. Everything matters.
However based on my experience, I follow a simple rule as I proved over and over it works every time - start from speakers and go up the chain - speaker cables, amp power cord, interconnects into amp, etc.

Plug the amp directly into the wall outlet without power conditioner

First power cord upgrade is for the amp - 10awg minimum, best possible cord you can afford

Second is for the preamp. Then on power conditioner feeding source components, then up the chain - preamp, DAC, streamer/transport

Also, I owned 3 Pass Labs amps - X250.5, XA30.8 and X260.8 monos. The generic 14awg stock power cord included with the amp is enough to get you up and running. But…every time a good power cord made a difference on these amps in my system. Even the affordable Audience Forte F3 beats the stock cord.

I have also owned many Pass, or Nelson Pass designed, amplifiers going back to the mid 1980's- and have found some improvements in replacing the beloved supplied power cord on some of them. I am currently using Audio Sensibility Statement cords on my XS150 monos - and was happy enough to go with them throughout the rest of my system. I will say - what I think made the most difference - was plugging them directly into their own dedicated 20A circuit. 

I’ve lost count as to how many power cords I’ve tried. My modus operandi is to buy a pc for an intended component. Evaluate it there for two weeks or so. Then reinstall the previous pc - and try the new one on other components for a least a few days each. Finally putting it where it sounds best for my ears. After cable swapping for 20+ years, I’m always surprised where it ends up. Even last week, I experimented with swapping pc’s that are already in my system. The results were very educational.

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. . . comes with a pretty beefy power cord

In my experience, beefy doesn’t correlate to SQ. There are many other factors involved.

@maxlarson

I am currently using Audio Sensibility Statement cords on my XS150 monos - and was happy enough to go with them throughout the rest of my system. I will say - what I think made the most difference - was plugging them directly into their own dedicated 20A circuit.

And Audio Sensibility makes great cables, for the money. I have a Testament power cable on my Plixir power supply and one lying on my floor right now. And knowing what I know now, I would agree if someone asked "is it better to upgrade to a $500 power cable or get dedicated circuits" I probably would agree getting the dedicated circuits would be more beneficial. But your experience sounds familiar to mine: I’ll repost my impressions from the "Zavfino" thread from over a year ago when one goes from a good $500 power cord to a power cable in the $1000 level. Again as always, this is my results, with my former equipment, my ears, my system, YMMV. (I tried to post a link to the comment but I don’t think it goes to the actual comment, it goes to the beginning of the thread)

Thought I would chime in with my experiences regarding power cable upgrades.

I don’t post here on Audiogon often, so I will add a bit more context. Going back several years I of course was one who was skeptical (to say the least) regarding high end cables. Over the years I have noticed having more education in science compared to the masses makes it even tougher to think outside the box and be a believer. Anyone else remember going back to your early 20’s after a few years of university how much of a "know it all" we thought we were? I understand capacitance, inductance and resistance. If a scientific instrument cannot show the difference between cables, if we can’t prove any sonic differences beyond a reasonable doubt knowing how emotions/bias/ monetary gain and pride can influence our decisions or claims then there must not be any. Sound familiar? Caught any ASR cult posts lately? These "do cables make a difference?" posts keep coming, and there is always a post from some electrical engineer (probably recent grad) giving his 2 cents worth.

Going back even further before forums or internet was even invented I was reading and touting Julian Hirsch’s publications. I was a subscriber. I bought that Sony amp over the Creek because it measured better. Boy was I an idiot. I have since grown up :) I accept the fact that there is no instrument on this planet that can measure better than our ears. Even my ears which only go to 16khz.

About 20 years ago I began to accept that not all copper is the same, and yes sound improvements can be had by changing cabling. That simple opening of the mind from "no I don’t need to hear it, because I know it makes no difference" to "well ok, I’ll give it a listen" is a huge step. Did alot of reading. Common sense says there is no way these hundreds of people are imaging things with their claims of improvement of sound with a simple cabling change- Are they all organized in some conspiracy? How could this many people be delusional? There must be something worth investigating. Even at this point I told myself that there is no way I would ever buy $1000 dollar cables; even if it made some little difference how can I justify spending this over just upgrading my amp instead? Or buy better speakers? I would just look into construction, and if they are all made the same then they must sound the same, right? Just buy the cheapest OCC cables you can with good quality connectors and replace the throw away cords. A few hundred bucks, okay, and hey, If some rich guy wanted $10,000 jewelry for this stereo that’s fine. I mean how much better does a Rolex tell time compared to a Seiko? But if it looks nicer have at it- it’s your money spend it any way you like. And so I read reviews of some budget friendly well-constructed cables: Audio Sensibility, and bought several Testament OCC XLR’s, some Transparent IC’s from Audiogon, and the last speaker cable I will ever need: Transparent Plus. I can’t believe I spent over $500 on a demo set of speaker cables! But man those fat things sure looked nice ;) And yes they brought sonic benefits over what I was using before. Well a few years later, a little more knowledge, understanding, and cognizance and reading and I have since upgraded the Audio Sensibility testaments to Acoustic Zen silver reference XLR’s and Absolute speaker cables. And yes, they make the DAC and amps sound so much better.

But power cables? It makes no sense; there are hundreds of feet of 50 cent a foot romex to the stereo, how is it possible that last 3 feet would make a difference? I already have dedicated circuits and a hubbell outlet. Well with the Audio Sensibility Testament it did, but I will admit I don’t recall it being huge, but a positive difference was noticed. Meh. Ordered a few more over the years.

So, last year decided on a whim to try a "real" power cord. Again, how could @thyname ​​​​@lalitk and so many others be exaggerating these sonic improvements? I thought about Wireworld, Audio Sensibility’s signature, Shunyata and after reading this thread Zavfino- Who the heck is Zavfino?

Ordered a Silver Dart power cord- thought about the lower level offerings but go big or go home. Well holy shit- it wasn’t a "I think it sounds a little better, but after burning in it should be better then I will re-evalute" it was absolutely and immediately a HUGE improvement: instruments immediately sound louder- check volume, yes it is the same- how? There is much more presence- detail easier to discern- separation between instruments- that grain you didn’t know was there was gone. I believe it was more of a difference than my last amp change (from Mcintosh to Nord) How could this be? Unbelievable. I still don’t know how 3 feet of "copper" makes such a profound difference, but it does. The Audio Sensibility Testament was a quality cord, with EMI/RF shielding, but sometimes in life you get what you pay for.

It has been about 6 months, I have a new found priority regarding my power. I ordered 2 more Silver Darts, I replaced my previous power conditioner with a Puritan PSM 156 (another huge improvement; highly recommended)

Just before writing this overdue impression of this exceptional Zavfino product I decided to put back in a Audio Sensibility Testament power cord between the Puritan and the high channel Apollon NCX500 (I use a Marchand active crossover to the Maggie 3.6’s). The soundstage just collapsed- all instruments are harder to pick out- major sounds are less prominent- lower level sounds have much less detail- more grain. No double blind test needed here- It is so obvious! Again, I don’t understand how music can sound so much better with a 3 foot power cord, but when listening to music with all these "fancy" cables I don’t care about measurements that can’t be done. I have no idea if this Silver Dart is the best power cord at it’s price; maybe at some point I will try some other power cords but there are many other things I will do to my system first.

Thanks @thyname for starting this thread. :)