Are dedicated lines enough?

So I’ve been slowly getting things squared away in my new sound room. For those who may recall - six dedicated 20A circuits, each feeding its own outlet, the circuits being fed directly from the main cutoff to my house via its own dedicated 100A breaker, bypassing everything else in the house. All of my source gear is running off a P20 on one circuit. My Pass X260.8 monoblocks off their own circuits nearby each amp. When I first turned everything on I was thrilled that I finally got rid of the annoying hum that I’d get when the amps had been plugged into the old circuit (the room originally had only one circuit off the house’s main subpanel). It sounded like heaven.

Now because of that problem I had had, in my old room configuration, I had to plug into the P20 - with 20’ Amazon Basics extension cords :anguished: running from the amps to the regenerator - to get rid of that hum. I thought even with a room that was only poorly set up for audiophilia, the result sounded pretty darn good. In any event, with the room all done I’d been listening with the amps into their own outlets. I’d been spending the last months just getting used to the sound of the new room and all, picking out the new and improved things I’ve been hearing, optimizing things like the power cord to the P20 and the new ICs from my phono preamp, figuring out when I’d get around to running REW for the next phase of acoustic evaluation. No, I don’t rush things. :rofl:

But I got to wondering - surely now that I have this fabulously designed dedicated electrical subsystem, there’s no reason to plug the amps into the P20…. is there? I finally ran some listening sessions first with the amps in their direct circuits, and then into the HC outlets of the P20, again using these ‘who knows how good they are?’ extension cords. I asked my wife to lend her ears to the experiment. It was unanimous, and it didn’t take long. Even with an electrical system that is as good as I’ve ever seen, or not heard, my system sounds better with the amps plugged into the P20 - even through these nothing extension cords! The bottom line is a greater sense of blackness, openness, and clarity. Night and day? No. Jaw dropping? No. But if I modestly say for among the best systems I’ve ever heard, even this relatively small difference is noteworthy. In my system the P20 makes everything sound better.

Update: I changed the title of the thread to more accurately reflect what’s going on.

1 Like

Curious. What does it measure the thd as in your dedicated electrical runs?

When I built my place I had five 20 amp circuits built in. I also have a P20. A dedicated circuit, one with separate ground rods from the house system, using conductors spun from Angel Hair, the really good stuff. All that care delivers power from the grid that has 7% noise in it. So the P20 takes care of that nonsense for everything but my amplifier. Plugging the amp straight into the wall gives it noisy power. But I have found, at least from the companies I buy from, the Amp is designed to deal with substandard power. So for me, plugging the amp into the P20 tends to sound exactly the same as straight into the wall. That’s what I have experienced here.

By the way, I had a couple of situations where I needed a 25 foot cord to deliver power to a system. I go to Home Depot or something similar and I buy heavy duty outdoor power cables with 12.2 AWG lines. It might have cost $60. That makes me chuckle, oh no not $60 for one cable! But it’s worth it. I don’t know about Amazon Basics cable but if I had to guess it isn’t quite as good. Maybe.


On my existing home circuit that I was using, before the dedicated subsystem was put in, the THD on that circuit was (as measured with a Fluke 125B Scopemeter in Harmonics mode) 6.51%. This essentially matched what the P20 was telling me. Now it’s 3.2%. Still enough to matter? Perhaps. But all the dedicated lines, low impedance single point grounding, and twisted THHN in the world isn’t going to correct the garbage quality electricity coming in from the grid.

Yep. There’s only so much a good in home electrical subsystem can do. I guess in my case, in my house, the Pass monos like it better running from the P20.

Like I said, the difference is small - I’m guessing most non “audiophile-maniacs” :crazy_face: wouldn’t notice. But it’s there.

1 Like

I have a couple Pass amps, an XA25 and some XA60.8s. I can’t hear any difference between the dedicated 20 amp outlet and the P20 with any of them; no improvement and no deficit. So I leave them plugged in for the protection.
All of my preamps and source equipment are massively improved by the P20.


Maybe the XA’s are more immune to being influenced by power line harmonics? I think it may also just show that total system synergy for different audiophiles can yield different results even if some equipment is the same. What a hobby. :expressionless: :roll_eyes: :wink:

…could also be my ears :worried:

1 Like

The human machine is the most important - and most complex - part of the audio puzzle!

1 Like

I added two dedicated 20A lines with Wattgate outlets two years ago. Well worth the cost of $500. Before the dedicated lines my P10 made a nice improvement, after, only a slight improvement, so I sold the P10.

Are you running everything direct into those two pair of outlets?

Or, it could be that maybe I shouldn’t jump the gun, and do a better job of figuring things out! :man_facepalming: I have the advantage of being able to listen all day for as long as I want so I’ve been listening. Yep, system definitely sounds better with the amps into the P20. But then it struck me - what am I listening to? Is it the P20 all by itself? That plus the Frankenstein arrangement of Amazon plus Pass power cords? I decided to try running the amps off their own outlets again, but this time ditching the stock Pass (Ching Chen) cord and using something better. Unfortunately I don’t have two cords of the exact same type in the needed length, but I do have one Shunyata Alpha NR and one Sigma NR… so I powered one amp with one and the other with the other. Yes, yes, I’ve just lost my “real audiophile” membership, but it was just a test! :shushing_face:

What did I learn? My biggest problem running the amps with their own cords into the outlets is that - the stock Pass cords sound like :poop: in my system! That seemingly was the biggest problem. Even with mis-matched cords the improvement was obvious, to the point now where it seems to me maybe I should try to find a good match there before I insult my dedicated lines any further (sorry, dedicated lines!).

It’s clear the P20 does engender an improvement, but will it be as large if I otherwise run good power cords with the amps? I’ll have to find that out. Maybe what I was really hearing was the P20 saving my bacon from a cr@papy run of power cords between it and the amps.

Unfortunately I can’t afford two Audience Front Rows! The Shunyatas show me what’s possible, but even in that mixed up configuration I still got the feeling they wouldn’t be an ideal match with the Pass sonic signature. I could be (once again :face_with_open_eyes_and_hand_over_mouth:) wrong however.


I got five dedicated lines. My system is better and into the P-20. It can handle it with sane listening levels. I can now use shorter more expensive power cables by plugging all into P20. So it has perks

Unfortunately the only way for me to get the best of both (shorter, better power cords and a PowerPlant) is to unbox my P15 and set it up between the monoblocks! :astonished: :roll_eyes: :man_facepalming: That’s not something I’d want to do!

Yes that is my set up. I thought of having P20 handles anodized silver to match mMcIntosh amps better. The P20 aesthetic contrast with pass too much

Sounds like you need 2 more P20s, one for each amp.

Thread title updated.

So. I asked about your thd because mine is about 1.1% and .1% with my p10. I don’t know how I got so lucky. I built the room and only have my stuff on the circuit. But not dedicated like yours. My power lines are under ground. Transformer box out in front of the house. I wonder if that makes a difference

1 Like

I put in dedicated line recently as I have three 100A lines coming into my house and one of them is only used to charge a car, so the stereo is on that. I have a conditioner that does a superb job, but wondered about putting in more lines should I go mad and buy a component system with big power amplifiers. There are high current, low inductance conditioners on the market that have only one outlet, so you can get one for each amplifier and plug it into the wall. Although I have a dedicated line, given how effective the conditioner is, I wonder whether the dedicated line is needed at all. Not that it matters, the impedance is 0.19 ohms.

It very well may! 1.1% is pretty darn good. I wonder how your system would sound without the P10?