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.
Dedicated 20 amp lines/should i use a sub panel
Happy New Year to all!!
I am about to install 3 - 20 amp dedicated lines for my stereo. I still have space in my 200 amp main panel but was wondering if their is any benefit to installing a 60 amp sub panel for the 3 audio circuits , also as i am using 10 gauge wire and its not the easiest to manipulate should i hook up the bare wire to the receptacles looped around the screws or inserted in the holes or should i use spade connection's. any advice would be appreciated.
Thanks in advance
Chris
I am about to install 3 - 20 amp dedicated lines for my stereo. I still have space in my 200 amp main panel but was wondering if their is any benefit to installing a 60 amp sub panel for the 3 audio circuits , also as i am using 10 gauge wire and its not the easiest to manipulate should i hook up the bare wire to the receptacles looped around the screws or inserted in the holes or should i use spade connection's. any advice would be appreciated.
Thanks in advance
Chris
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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 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. |
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. |
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 agree with dill as well, no need for a sub panel, jmho. noromance @noromance, 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? Did you use Romex? 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? Is it possible one of the 2 is running parallel next to some other branch circuit? Jim |
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. |
noromance >>> Same leg/busbar. One 20A breaker above other.If the breakers are directly above one another, there in on the same side of the electrical panel, they are not fed from the same leg/bus bar. (For standard size single pole breakers.) One is fed from one leg, Line, and the other is fed from the other Leg, Line. You can easily verify this with a multimeter. Insert one test probe in the Hot contact of an outlet fed from one dedicated circuit and the other test probe in the Hot contact of the other dedicated circuit outlet. ~ If both are fed from the same leg, Line, bus bar, the meter will measure zero volts. ~ If the meter reads 240V, nominal, then one circuit is fed from one leg, Line, and the other circuit is fed from the other leg, Line. Did you use Romex?8-2 with ground? Not 8-3 with ground? Jim |
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, 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. |
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. |
@noromance, From the picture of one of your mono amps you are not using the green safety equipment ground wire. I assume both amps are wired that way. https://systems.audiogon.com/systems/1593#&gid=1&pid=11 How about the preamp, are you using the safety equipment ground on it? I also noticed the steel cover plate on the single receptacle outlet. https://systems.audiogon.com/systems/1593#&gid=1&pid=14 Not that it would cause the hum issue, it could have an effect on the SQ. Just for the heck of it pull the steel cover off the outlet and see if you can hear a difference. If yes just install a nylon plate in its’ place. By the way, nice looking vintage equipment. Just an added note. I ran two 10-2 with ground NM-B cables, (Romex is a Trade Name manufacture of NM-B sheathed cable), around 75ft each in length. Preamp and amp are tube. System is dead quiet. Ear right up next to the drivers of each speaker. Jim |
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. |
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noromance said:The DIY 4 duplex plate appears to be stainless steel. It may or may not have ferrous materials in it. It depends on the grade quality of the stainless steel. You can use a magnet to check it. If the magnet sticks to the plate like glue or is attracted to the plate replace it with a non breakable nylon plate. Change that single receptacle steel cover plate if that is the outlet that’s feeds the DIY power distributor. Jim |
Al, (almarg), By chance have you been following the exchanges between noromance and me in response to this post of his? noromanceBoth mono block amps are floating the safety equipment ground. When everything is fed from one dedicated circuit no hum. When the other dedicated circuit is used to feed the other amp he gets the hum. Is there a chance the hum is not caused by a difference of potential between the two equipment grounds of the two dedicated circuits? Just a gut feeling I don’t think the equipment grounds are causing the hum. And how would you explain this? noromance But it doesn’t when I add my REL sub.??? Any ideas? Suggestions? How about if the mono amps are using an AC Line filter cap/s and maybe one or both is leaking to the chassis of the amp. What if the hot and neutral AC polarity is reversed on one amp with respect to the other? https://systems.audiogon.com/systems/1593 Again, any ideas? Jim |
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 |
noromance@ noromance, Is this the schematic wiring diagram for your amps? http://www.freeinfosociety.com/electronics/schematics/audio/pictures/eicohf22.gif If so, see that C13 (.03 600V) cap connected to the AC line that is connected to the chassis? (Just to the right of the AC line fuse). That would have to be removed before connecting an equipment ground wire to the chassis. That’s the cap I was attempting to ask Al about in my previous post. I forgot it was/is referred to as a "death cap". (Thanks imhififan for the 2 Links above.) I always wondered why the cap was installed on the fuse AC line and not on the non fused line. With the old original non polarized plug the user had a 50/50 chance of plugging the plug into the wall outlet and getting the neutral, (The Grounded Conductor), the line the cap is connected to. Again note the fuse would be connected to the neutral line. I guess back in those days electrical safety was seen different than it was in later years. One example, old Knob and Tube wiring the HOT was ran directly to the ceiling light and the neutral ran through the switch on the wall. The amps, at the time they were designed and built, were not designed to be directly connected to an equipment ground. You will be connecting the amplifier’s circuit ground/signal ground directly to the mains safety equipment ground. I am not sure if that will improve the SQ of the amps or harm it. Someone like Al or Ralph would need to chime in with their thoughts. Jim |
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 |
@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. |
Al (almarg), Thanks for responding to my above post. I was thinking the same things as you stated in your last post. And no doubt circuit grounds/signal grounds are more than likely connected to the chassis at various places. Would you leave the cap where it is now located on the same AC line as the fuse? For proper operation the cap should be connected to the neutral conductor. Problem with the way it is now the neutral is fused. (I remember reading somewhere the user should reverse the 2 wire plug in the wall outlet for what sounded the best with the least, buzz/hum/noise.) I think for a test I would first lift the cap from the chassis and then check for the proper, correct, AC polarity orientation for the primary winding of the power transformer. That will determine which lead of the primary winding should be connected to the Hot conductor and which lead of the winding should be connected to the neutral conductor. Hopefully the AC line that is fused will be the Hot. There’s 50/50 chance. I doubt back when the amps were built anybody back then checked. 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. I would check and wire both amps the same. (Of course for many years the plug for the amps were a 2 wire non polarized plug that had a 50/50 chance of the fuse being fed from the mains Hot conductor.) Al, what do you think? Jim |
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, 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 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. |
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/ |
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. |
@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. |
@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. |
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 |
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 |
@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. |
@handymann Every other single breaker space down each side of an electrical panel is the other Leg, Line. Example for a 120/240V single phase electrical panel: First top breaker space on the left side is L1. The first top breaker space on the right side L1. The second space on the left side is L2. The second space on the right side is L2. The third space on the left side is L1. The third space on the right side is L1. The forth space on the left side is L2. The forth space on the right side is L2. And so on down each side of the panel. NOTE: Some GE single phase load centers have a funky breaker connecting bus that will accept standard size breakers as well as "slim" size breakers. With this load center if 2 slim single pole breakers are installed side by side on the same side of the panel it is possible both may be connected to L1 or both connected L2 Or one might be on L1 and the other on L2. To make thing even more confusing there is a 2 pole "slim breaker" for 240V loads. Extreme care must be taken when using this GE load center. There may have been other manufactures that use standard and slim style breakers as well. GE is the only one that I know of. https://www.superbreakers.net/1-pole-circuit-breakers/thqp120 https://www.lowes.com/pd/GE-Q-line-Thqp-20-Amp-2-Pole-Standard-Trip-Circuit-Breaker/1099039 Jim |
