Dedicated 20 amp lines/should i use a sub panel

So many responses, I apologize if this was already said:  make sure all lines come off the same side of your 220 line. 

@Al- Yes, it makes sense to measure the voltage to narrow down the issue. I haven't upgraded the Parasound Halo-A21 amplifier because of two issues, room acoustics and power quality inconsistency issue that we are currently discussing. I have somewhat handled the room issue with GIK hybrid Alpha panels and wanted to ensure a good clean power feeding my music room before spending any money on the electronics. I have more or less decided to go with Pass Labs XA100.8 mono blocks when I am able to resolve these issues. 

@Peter- Is it worth spending $10K to get a branded transformer from Equitech or Torus instead of getting a Commercial Power isolation transformer at a much cheaper price?

Thank you all for responding to my queries.

A balanced power transformer is most definitely an improvement and well worth it - I use them - one for my power amps and one for the front end.

The slight hiss you hear is generated by current running through resistors,  transistors and other components in your amplifiers - all electronic components have this to some degree.  Some resistors have lower noise than others, same goes for Transistors etc.  Its not something to worry about.

Good Listening

Peter

Hello Indranilsen,

The first thing I would do before deciding how to proceed would be obtain a multimeter, if you don't already have one, and measure the AC line voltage at various times of the day and night over the course of several days.

If you find that there is a correlation between the variations in sound quality and changes in line voltage, a power regenerator, such as one of those made by PS Audio, might be a solution. A regenerator is likely to also be helpful if noise or distortion on the AC line is contributing to the problem. On the other hand, though, some people have reported here over the years that in their systems some regenerators have resulted in compromised dynamics.

Also, in a thread several months ago you indicated that you were considering upgrading your Parasound Halo A-21 amplifier. If you haven't yet done that, I would suggest that you re-assess the situation after purchasing the new amplifier before deciding how to proceed. It's possible that a different (and presumably better) amplifier may be less sensitive to the power line anomalies at your location than the present amplifier.

Good luck. Regards,
-- Al
 

@noromance/@lak,
Thanks for your feedback.
It seems like the hiss coming out of the speaker tweeter is a non-issue and in-reality that's not bothering me at the moment. So I would ignore it....
However turing off all lights/heaters/furnace etc is not going to be a realistic solution... Would a balance power transformer with its so much advertised common-mode-rejection functionality be able to  address the inconsistent A/V performance issue during day/evening? These items are expensive and relatively difficult to install, specially the units that connect to a 240V power supply. That's why I wanted to get an idea from this group before getting started on this project. For those who have this or similar power issue what do you do to avoid/eliminate it?
Thanks.

@indranilsen, AC power coming into our homes is always in a state of change. Fewer people up after midnight using power so the incoming AC could be less polluted as noromance stated.

A balanced power transformer could possibly allow you to hear more details in the music and maybe even a better soundstage however it might not necessarily get rid of the slight hiss you hear from your tweeter.
Personally, I wouldn't be concerned of the hiss.

Welcome to the perennial problem of dirty power. Turn off all dimmers and use only incandescent bulbs. Heating boilers, appliance motors, phone charging adapters etc all add noise. Note that your hearing is more sensitive late at night so music sounds better then.

Hello,
I have a question for this group regarding an issue likely related to power that I face time to time in my music room. It seems that audio/video quality fluctuates during the day/evening and I get the best quality (audio/video) only after midnight. I have two dedicated 20 Amp circuits (10 gauge wire) with a pair of Furutech receptacles which feed all of my AV components. I don't have any power conditioner but use a Nordost power distribution unit. My system is relatively quiet with no 60 hz hum. However there a slight hiss that comes out of my Aerial Model 7T speakers when everything is powered on but it is only audible if you take your ears very close to the tweeter.
Could anybody comment on the possible root cause behind the inconsistent audio quality throughout the day?
I am thinking of installing a balanced power transformer but not sure if that (isolation) would address the inconsistency issue. I would love to hear your opinion on this as well.
Thanks.

If the cap have to be in use to reduce noise, I think it is worth to confirm that if the C13 ( .03 600V ) been modified and connected across the Hot and Neutral, the cap should be a class X cap, and if the cap is connected from Neutral to chassis then a class Y cap must be used.
https://www.allaboutcircuits.com/uploads/articles/ND_x-class_y-class_safety_figure2.jpg

https://www.allaboutcircuits.com/technical-articles/safety-capacitor-class-x-and-class-y-capacitors/

Noromance, sounds like a plan! FYI, though, the manuals I’ve seen for various REL subs recommend that when a single sub is used in conjunction with monoblock amps, and is connected at speaker-level, the black wire should preferably be connected to a ground point on the preamp. That may be worth trying when you get a chance, as you **might** find that sonics are improved at least slightly.

Jea48 1-5-2018
For proper operation the cap should be connected to the neutral conductor. Problem with the way it is now the neutral is fused....
At any rate if possible I would want the fuse on the Hot mains conductor and the cap connected to the mains neutral conductor to chassis ground.

Jim, the photo in Noromance’s system description of the underside of his amp, which as he mentioned has been modified, shows a somewhat different circuit configuration than the schematic Imhififan provided. It appears to show the fuseholder (and also the power switch) in series with the black (hot) AC wire. And although it’s hard to tell for sure, I think the cap is connected between the white (neutral) AC wire and chassis. So if that is correct, and assuming both amps are wired the same, what you are indicating should be done has been done.

Also, I wouldn’t be surprised if the modifier replaced the original power cord with a two-wire cord having a polarized plug, and in the process checked for optimal polarization. But as we’ve both said it might be worthwhile to try to verify that. The experiment I suggested in my previous post would provide some confidence that plug polarity is correct. A more conclusive way would be to disconnect the interconnect cables from the amps, turn them on, and use a multimeter to determine which plug orientation results in the lowest AC voltage between the chassis and the screw on the wallplate of the outlet. A cheater plug would be used for purposes of the experiment if that is necessary to reverse the orientation of the plug. To be sure those results are meaningful, though, it might be necessary to disconnect the electrostatic speakers from the amp as well as the interconnects. It should be safe to run the amp unloaded, given that it won’t be processing a signal, but personally my preference would be to connect load resistors in place of the speakers rather than running a tube amp unloaded even with no signal going into it.

Best regards,
-- Al

Thanks @almarg. Yeah, I'll try it with and without the safety ground and see what sounds better. Thanks for your vote of confidence in the amps' wiring! The Speakon black goes to the right speaker ground IIRC. Not sure I'll bother with the second run. It's fine and juicy as it is and I've other fish to fry (like a new idler wheel from AF for my 401!)

@noromance

If you can’t solve your problems with breaker assignments, etc., for whatever reason, consider an isolation transformer. The added benefit is over-voltage protection from an electrical disturbance such as a lightening strike or a transformer event.

Of course, this comes at a cost. First, they hum while they work, so they must be sited outside a music room. Second, some electrical inspectors don’t understand, and get tense or weird. Third, they aren’t cheap. But they do work. I have one in front of everything which produces signal: ESL power, amplifier power. I also isolate motor controllers, but that’s just silly old me.

A separate ground was mentioned above, but I would be wary of that option unless you have a dedicated subpanel to which ALL the audio is connected, and it will always be that way. Otherwise you invite a ground loop of heroic proportions. Typically the ground plate is supported by fresh water copper pipe, which does a great job (assuming a moist environment around the pipe, and of course, unless you have plastic!!!).

Plitron sells good transformers, bare and boxed, and they sell directly to the public.

Thanks for your thoughts and questions, Jim.  Generally speaking a direct connection between AC safety ground and signal/circuit ground is an invitation to ground loop issues (both hum and high frequency buzz).  In good modern designs the two grounds are often connected to each other through a resistor having a resistance in the area of 10 to 100 ohms, which would probably be impractical to do in this case since chassis is used as signal/circuit ground in many places.  It would also stand a good chance of being sonically undesirable, due to the small impedances it might create between grounds at different circuit points within the amp.  So I would recommend that Noromance leave well enough alone, and if he chooses to upgrade the power cords on the amps that he **not** connect AC safety ground within them.

Also, regarding the "death cap" (and thanks to Imhififan for providing the good reference), it's worth noting in the photo of the underside of Nomance's amp that the cap has been replaced with a modern one.  So presumably leakage within that cap is not an issue.

But it doesn’t [hum] when I add my REL sub.

Noromance, what model is the sub, and if you are using the high-level Speakon connection what is the black wire connected to?

Also, if you want to pursue the hum issue further what you might try would be connecting each amp to its own dedicated line, with the two lines on the same AC leg, and then trying all four combinations of the orientations of their AC plugs. If the plugs are polarized or are 3-prong types, even though the safety ground is not used within the amps, for experimental purposes you could try that using cheater plugs.

Regards,
-- Al

Looks like I should expedite my plan to rewire the power cords on the power amps with new OFC cables including connecting the safety ground. I’ve been meaning to do it after changing the power cord on the preamp with very positive results. Thank you.

When I did my Listening room installation, I moved most the rest of the house circuits to a separate sub-panel - but I needed the space breaker wise.  If  you don't need the space just use your existing panel, but have your electrician tighten up all connections.

I ran 12/2 to the outlets but the longest run is only 20 feet of wire,  I have 9 dedicated lines, one leg of the incoming power is used for the tubed system,  4 circuits.  The other is for my SS system,  5 circuits including a 220V one.

I don't get caught up in the Outlet craze - use Leviton Industrial grade outlets.

Running separate dedicated lines will be the single most $ efficient upgrade to your system you can do, the second one will be room treatments.

Good Listening

Peter

New house, ran 4 separate 20 amp circuits to 1 of the main panels. I asked my electrician and he thought that would be best. No hum or issues and have plenty of power for anything I want to use

Use levlok hospital grade outlets. They have pigtails and you connect it with wire nuts 

Audio Advisor has excellent Solid Copper gold plated 20 amp 
for $100 each , or their phosphor bronze gold plated 20 amp $50
night and day better then anything Hubble makes and the best buy
in top quality outlets  built to last and grips great. 
Look at the resistance index ,cheap home units zinc , brass ,
bronze 4x better conductivity , Copper 5 x .for the money 
the gold phosphor bronze  are fantastic . I am rebuilding my line 
conditioner with the exact one . You want great sounding cable inside your wall,
Analysis plus sells The best Audio cable by far that runs inside your wall a awg11 I believe you may pay 4 times as much as Home Depot crap but you will hear the diffference without question !!

noromance,
No apology necessary, i'm enjoying all the different opinion's and just absorbing all the info.
   

Thanks everyone, i appreciate the info. i guess ill forget about the sub panel as it seems like there is little to no benefit by adding it since the 3 runs will all be under 50 feet and i'm not going with an Equi=Tech as much as i would love too.

Jim,
Thanks. Correct - that’s how I received it from the seller. Not sure if Stu R. originally did that or if it was the seller. As the REL is fine and grounded, the hum loop may be from the monos. I dunno. The Croft preamp has the safety ground intact as factory supplied. The 401 is also grounded. Interesting notes on the steel plate. However, I’ll definitely try it on the DIY 4 duplex receptacle unit if I can buy one in that size. Thanks for your help and apologies to the OP for going a little off-topic.

How far away is the main panel from your listening room? If it’s more than 50 feet then it pays to put in a subpanel since a branch circuit of that distance will have a high voltage drop (3 volts with #12 and 1.8 volts with #10 at a 15-amp peak draw).

If distance is not an issue, use 10/3 romex because the wires are spiraled and that reduces common mode noise. Cut the bare grounding conductor and use the red wire for ground (tape it green where exposed, of course). Also, use the clamps under the screw of the receptacle for #10 wire instead of looping it around the screw. And use 10/3 from the subpanel to the receptacle also.

Jim,
8/2 with ground. You are correct about the legs. I also tried it on both legs. So instead of 22, 24, where I originally connected it, I had tried it on 23, 24 but it still hummed. In fact, as it’s a basement space, I just ran in a 12/2 on 15A breaker on the same leg to see if it still hummed with the (2 wire) monos. It did. But it doesn’t when I add my REL sub. So all is not lost! I should say that there is normally no hum from the rig.

Besides having built-in noise cancelling features, and surge protection, another advantage to the sub-panel is that you end up with a star grounding scheme that is short, and therefore much less likely to cause differences in ground potential.

The biggest source of noise in my mind is usually other household appliances, and dimmer switches. If you get separate runs, without any noise cancelling, you are literally just making it easier to pick up noise from anywhere in the house. Having a 30 to 60 Amp subpannel that has its own noise and surge protection is the key.

Best,

E

Jim, Some replies below.

By side by side, do you mean the breakers are installed directly across from one another? Connected to the same main bus breaker tie. (Both are fed from the same leg, Line.) Or, do you mean one is installed above the other, side by side? One fed from leg, Line 1 and the other fed from Leg, Line 2?
>>> Same leg/busbar. One 20A breaker above other.

Did you use Romex?
>>> Yes. 8/2 NM-B (not 10 as I said before) cable from Lowes.

Did you try to keep the 2 cables separated from one another at least 6" after getting them out of the electrical panel, as soon as practical? Especially a long parallel run?
>>>Yes. 12 feet apart.

Is it possible one of the 2 is running parallel next to some other branch circuit?
>>>It’s possible but not obvious.

>>>I also tried tying the ground wires to the same terminal, removing the ground (to test only) and moving other equipment to different runs to no avail. I’ll be honest, I abandoned messing around with it after an hour and removed one leg and used the cable for another project. The one 8/2 run on a 20A breaker into a 20A L5-20/L5-20P receptacle/plug sounds great.

Thank you, Larry (lak). Jim (Jea48) is the expert when it comes to electrician-type matters, and hopefully he’ll chime in. But FWIW I agree with all of the comments by Dill. I doubt that adding a sub-panel would provide any benefit, and as Dill indicated inserting additional contacts into the path won’t be helpful.

Unless, that is, the sub-panel is something like those made by Equi=Tech which incorporate a high quality transformer and would provide balanced power to the system. However their models cost in the vicinity of $10K or more, and weigh upwards of 300 pounds.

Good luck. Regards,
-- Al

I will be running 3 lines all identical in length to avoid ground loop hum, my interest is will there be any difference... negative or positive...from running a sub panel as opposed to just using open spots in the 200 amp panel. the closest and farthest line will each power a REL G1 sub and the centre line will power a Synergistic Research powercell 10 UEF, which is where my  tube cd, tube pre and ss amp are plugged into. this is how my system is presently powered just not with dedicated lines.

@almarg @jea48 there are othres also...
A little assistance, please?

I believe we need to hear from some of our more experienced professional electrical experts here on Audiogon (you guys know who you are).
I'd also really be interested in knowing if there is or isn't an advantage to using a sub-panel if there are openings in the main panel?
No offense meant to those that have answered above.
I also use a sub-panel in my systems.

My electrician recommended a subpanel and I'm so glad I went for it. His reason was my main box was a mix of old and new wiring and I was hearing noise thru my existing line to my Hifi rig.

He knew what he was doing since now I have two separate runs with no metal staples used, with two Hubbell receptacles grounded at the subpanel. He also added a second 8' grounding rod.
There is absolute silence thru my speakers now, and I'm using all tubes. I was able to remove one of my power conditioners since the noise floor is so low.

 

I don't think there's a big benefit, besides wiring alone, but there are some interesting options in terms of noise suppression and balanced power at the power panel.

Check with your electrician.

I ran 2 x 20amp runs on 10 gauge from 2 side by side breakers for monoblocs. I ended up not using one of them because of a hum loop. Let us know how you get on.

It is good not to introduce additional wiring and contact points, but...

it is also good to isolate the whole thing from any noise that reaches the main panel and a sub-panel could help with that.

Thanks dill, makes sense as not to add any extra contact points. i had just thought that by adding the sub panel the 3 dedicated lines would be better isolated from the rest of the houses electrical devices.

There is no need if you have space in the main panel. It is best not to introduce additional wiring and contact points in my opinion. The Furutech outlets are an excellent choice.

Just curious, why do you say not to use a sub panel. as far as my outlets i'm using Furutech GTX outlets. 

No, don't use a sub panel. I used 10 ga. years ago when I had my dedicated room, it is a bear to use. The best connection would be the screw. Use needle nose pliers to make a 3/4 loop and do not use spade connectors. Buy the best outlets you can. If you don't want to use audiophile duplexes, I recommend Porter Ports. These are sold on AudiogoN by Albert Porter and are cryo treated Hubble hospital grade.