BAT products seem to be more susceptible to hums than the average mfg'er.
The generic response is:
Lifting or floating the grounds or installing an isolated ground for these dedicated lines should help.
Also, ensure that no TV, TV cable, satellite, cable box, etc. are associated in any way with these new dedicated lines.
For best sonics, I would recommend lifting the grounds from all components except for the preamp.
-IMO |
What is "lifting the grounds"? |
Lifting the grounds means to use the "cheater" plug which in a three prong to two prong adaptor.
To continue a bit more....Stehno, you say, "or installing an isolated ground for these dedicated lines..." how about this situation. I have two wire service in my house. I was able to add a 20 amp three wire line for the stereo. There also is a 15 amp two wire line already there. Can I run a ground "jumper" to the two wire line? Would this help eliminate ground loops?? |
Try to use a Commercial electrician, they will have a better grasp on dedicated circuits for your application. Have him run a conduit to your proposed location, have him pull a seperate neutral with every hot(#12 is fine).
Then ask him to pull a dirty ground and an isolated ground. He'll probably ask you if your using I.G. receptacles? (just stare blankly into his eyes).
Explian that your trying to isolate every piece of gear from every other piece. If he's really good he'll ask if you want an isolated ground bar in your panel. Just smile and he'll understand. Then glance over and say, Do you think you can isolate the ground all the way back to the ground rod?
He'll either get a big grin on his face or jump in his truck and drive away cursing.
Personally I ran a 1-1/4" conduit to a 100 amp sub panel just outside my listening room. Then I installed an isolated ground bar and a dirty ground bar at my service panel and the new sub-panel. Next I pulled the feeders between the two panels (2-hots, 1-neutral, 1-dirty ground, 1-clean ground) Then I took six dedicated circuits with dedicated neutrals and two grounds up to my outlets (using smurf pipe). I custom ordered White I.G.industrial grade recptacles to match the decor of the room. (I did not cryo them because I'm lazy) I tied one hot one neutral and the Isolated ground to each receptacle. I tied the dirty ground to the box, hooked it all up and WALA!.
I also upgraded my service to 200 amps and cleaned up some of the house circuitry problems during the course of this work.
I'll eventually connect the Isoated ground bar to the ground rod when I have time.
This is the most bang you'll ever get for the buck IMO and in my 22 years working as an electrician in Silicon Valley.
Good luck! |
Glen: Am I reading this right? That your I.G. recepticles are "star grounded" to an isolated ground bar that is not (currently) referenced to ground? |
I've tied the I.G. bar to the panel ground bar with a jumper at my main panel temporarily :^(
This has been an on going project, and I still have a few loose ends to tie up before I can complete the true isolated grounding.
I'm not big on lifting or floating the ground.
But that's just me :^)
|
The short answer is: not necessarily. Try to minimize the number of dedicated circuits. Ground loop hum probability increases with each grounded power cord you plug into different outlets on different circuits. Sounds counter-intuitive, but one circuit for all your gear gives the greatest possibility of eliminating ground loops. That's because all of your grounded plugs terminate at the same point in the circuit - preventing ground planes from being created.
If you plug each component into its own dedicated circuit, you now have multiple circuits with different lengths (from the breaker, the wiring and the power cords)creating a ground plane - a "rectangle" of wires. These different lengths have different resistance and with that come voltage potentials created along the ground planes. This causes induced stray currents in the ground wiring (or conduit or BX) - the cause of ground loop hums.
IMO, add additional circuits only if absolutely necessary. I have three circuits: two for mono block amps (due to power draw) and one for the entire front end. No problems whatsoever with ground loops since all three circuits terminate in the same gangbox resulting in all outlets haven the same ground conductor length. I'm sure others will have differing opinions, but this is what works for me. |
Max, lifting the ground is far better done NOT at the male AC via a cheater plug but by USING an existing PC's shield as a floating ground and lifting at the component end (IEC) to further possibily reduce noise.............
Interesting thread. I usuallly advise running a MAX of 4 dedicated lines: 2 for big monos, one for all remaining analog, and one for digital, and then reduce the number to three if only one amp OR the digital can remain on a dirty preexisting house line, or two if both of the above, or just one dedicated line if the system just comprises an integrated amp for the dedicated line and the CDP on the vestigial house line. As long as the dirty digital is kept well-isolated from the low-level analog pre.
Nice posts, guys. |
Thanks for the responses guys.
I am planning on going with five dedicated lines so that one line on each side of the room can be used for a powered speaker and a subwoofer. One line for analog, one for digital, and one for the amp. I am also considering going ahead with a sixth dedicated line which would be used for my second amp if I decide later to monoblock my amps.
My plan is to use 10/2 romex throughout the rewiring project with equal lengths of wire being used on all circuits. I will also be checking with PartsExpress to see if they have any 10 gauge solid core 99.95% OFC AC wire. My plan is to go 20 amps on each dedicated circuit.
I have decided against the Wattgate outlet because of expense and go with a cryo treated Hubbell 5362's but would like to hear your opinions of that change and make suggestions if there is another you like better.
I don't want to overkill this process, but I would prefer to get all the wiring done at the same time and be done with it.
Glen and Subaruguru...I will be using your suggestions when I discuss this installation with my licensed electrician. If you have any other suggestions, I'd love to hear them. |
Jcambron, if you are installing 6 dedicated lines, I'd suggest making sure that the line lengths are fairly short. You might consider a subpanel near your listening room. Then star ground with equal length wire runs from the subpanel to the outlets, and see that the lines are on the same phase, with the main household items on the opposite leg. Regarding outlets, I like the Hubbell 5362's a great deal but haven't compared them to Wattgates. |
Thanks for the invite to repost, Jc. I further agree with Flex fully. If the lines are long, using a sub with a FAT feeder will reduce loop potential. As well the 5362 is my favorite duplex (disclaimer: I have a bunch for sale for only $10 each). No sense paying extra for Hospital unless you need explosion proofness, eh?
Further, I really do believe is using a better dielectric for the dedicated lines that will serve the components that handle the low level audio signal, especially the analog.
So I'd suggest using the Belden 83803 (another disclaimer, as I sell the stuff "preburned in") for that analog line, and possibly for the digital...again as ong as they're kept separate. If the lines aren't too long, it'd even be better to put 5 lines on the sub-panel and run the digital one separately back to the main instead of through the sub!
Be aware that solid 10AWG is a bare to wire in tight duplexes, so leave a bit of room around corners, etc. The 12AWG 83803 is MUCH more installation friendly.... |
