weird problem

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filmguy
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#1 erstellt: 08. Apr 2005, 21:40

hi i just bought the klipsch rw12 sub and have a few problems i hope u guys can help me with

1) bcoz my HT is in my bedroom i have to run a 15m cable for the sub. while setting the sub i noticed a very unusual problem :
when i connect any RCA cable to the amp and touch the other end of the cable i get a slight electric shock. but this happens only in one particular end of the room (where i intend to place the sub); everywhere else nothing happens when i touch the RCA. at the same troublesome part of the room when i connect the RCA to the sub i get a bit of a shock when i touch the ON-AUTO switch (made of metal) at the back. what could the problem be?
will it affect the sub in anyway ? i hope not bcoz there really is no other place i cld really position it.
by the way i also tried different RCA cables and different sources (DVD player instead of amp) and i still get the shock at the same area.

2)so far i was using the LFE input. i was told that if i use the y-connector to use the line-level inputs i'll have greater output. but when i try that i get a very loud hum (almost a sorta distortion). this disappears when i use the LFE or either the R or L line-level input. i am using a DIY sub cable (RG-6 wire). this hum happens wherever i place the sub, in diff parts of the room, even where there is no other issues.

3)if i'm restricted to using the LFE input what am i losing out on ? is the variable phase disabled ? the sub crossover anyway is useless to me as my marantz sr4300 reciever only has a fixed crossover point of 100hz when is set the fronts to "SMALL" ( i have bookshelves with a lower 3db limit of 45hz)

hope u guys can help me out.

thanks

myriad
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#2 erstellt: 09. Apr 2005, 03:25

IMO you have a ground problem at the troublesome part of the room. The supplied cord with RW12 is two pronged. You need to run a ground wire from electric outlet and connect it to any chasis screw of your sub.
If you don't want to get into any of this, just replace your stock cable with three pronged 2.25sqmm Volex cable. These cables are available at computer shops for around Rs.100/- and are much better than stock cables.
You can also try FINESSE.
The variable phase will be disabled with LFE.
I don't think you will lose much with HT but im not sure about stereo playback. For me, a sub with 2 channel stereo has always been disappointing.

big-ears
Stammgast

#3 erstellt: 09. Apr 2005, 06:34

Hi Filmguy,

Reply in order:

1. Obviously a grounding problem. Check at other outlets whether the same happens. Ground wire should solve the problem.

2. I think I had cautioned you earlier about the 15 m cable resulting in humming. Anyway, since the LFE input works fine, you may use that.

3. Don't think you would be losing much with the LFE in HT. However, you can keep the amp closer to the sub with the line level connection for a trial to find out for yourself if you really are losing anything

filmguy
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#4 erstellt: 09. Apr 2005, 22:23

thanx for the advice myriad & bigears.. i plan to call an electrician in the next day or so to check things out.

actually i dont think i explained the shok thing well. see my whole setup(amp, tv, front spkrs etc.) is on the west side of my bedroom and my seating is on the east side. now when i place the sub on the east side is when i have the problem and the problem really isnt with the wire bcoz when i attach the sub in other outlets on the west side its fine. infact its not only the sub that gives a shock. i carried out an experiment where i connected an RCA wire to the sub out of my reciever and holding the other end of the wire to my finger i carried it across to the east side where at diff places i feel a slight shock that varies from a buzz to something sharper. this happens along the whole east side of the room. and it disappears everwhere else. so thats the strange thing - its almost like that side of the room is charged or something!!
bigears - the 15m wire itself isnt creating the hum. when i use the same wire on the LFE or singly on the R or L input of the sub theres no prob. only when i use the y-connector. so thats something else thats weird! i checked out the y-connector on the TV and theres no prob with it.
my main concern is that i dont damage the sub by placing it there in that section of the room as i wont really be touching the ON-AUTO switch or RCA on any sorta regular basis.
i hope u can help me solve it coz i dont know if the local electrician knows abt these things.

big-ears
Stammgast

#5 erstellt: 10. Apr 2005, 03:50

Hi Filmguy,

Hmmm... now that you've brought in the east / west location angle, don't think a simple electrician will be able to solve your problem, you need to call in a Feng Shui expert!

But seriously, if the outlet in the east section is giving you the problem whereas the outlets in the west work fine, the problem seems to be localised to that particular outlet. During your experiment, was the receiver connected to the western outlet and you still got a shock when you crossed over to the eastern side? Some magnetic field problems?

Sub humming due to ground loop is quite a tricky issue, sometimes it happens and sometimes it doesn't, but with a 15 m cable the sub would be more prone to humming. I once bought an expensive 8 m sub cable and found the sub humming in the LFE mode, whereas a cheapo Y splitter / RCA cable worked fine! Anyway, you are lucky the LFE connection works fine.

As regards the eastern side being charged, we should turn to the electrical whiz-kids on the forum to offer us a plausible explanation....

filmguy
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#6 erstellt: 10. Apr 2005, 10:43

big-ears schrieb:

During your experiment, was the receiver connected to the western outlet and you still got a shock when you crossed over to the eastern side? Some magnetic field problems?

yes, thats right. the amp was kept in the normal westside and i took the rca all over the room and it gave the shock only on the east side.

my main worry is that my sub shldny get damaged by this phenomena as i really hvae no choice in its placement.

the sub hum with the y-splitter comes even with a normal 1.5 m wire too.

deepug
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#7 erstellt: 10. Apr 2005, 14:45

Hi

I think this is due to some electro magnetic interferance ? I am not too sure . Check with you building plan and see whether it's through the eastern section the concealed electric wires are passing. Could be the reason

Best regards
Deepu

SUB_BOSS
Gesperrt

#8 erstellt: 11. Apr 2005, 06:31

Hi Film guy I too have the same problem...shocks now and then .here and there......kinda tingling when i touch the components....or Rca's .....any comments.....

one answer from my brother was wrong electrical wiring execution at the fundamental level....so has to be done from ABC....... and my landlord is a miserable miser...so thinkin of changing pad....

cheers......

chhhbuuuurppppppp

filmguy
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#9 erstellt: 11. Apr 2005, 13:36

well the electrican dropped by and as i suspected he was clueless abt things.

anyways i'll try the 3pronged cable as myriad suggests and just keep using the LFE input. changing wiring and all seems impractical so i hope the phenomena, whatever it is, doesnt have an adverse effect on the sub.

ravi
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#10 erstellt: 18. Apr 2005, 15:27

This problem is very interesting. The entire east side of your room seems to have a very strong electromagnetic field or some such. If that is the case, the hum with Y-splitter could be easily explained, as the ground shields of the two RCAs in the Y-splitter would form a loop in this configuration - and the strong magnetic field would induce a hum voltage in this "ground loop".
This same field might be inducing more than 40V in the wire as you carry it around your room, causing the tingling shock!
Do you have any equipment in that side of the room that can produce these fields? I am not sure any amount of concealed electrical wiring can cause this magnitude of fields.

Conversely, it might also be that it is the westside which is all charged up - and it discharges through your body when you touch the RCA on the east side! So might be worthwhile checking for damaged earth wiring on west side or faulty equipment with a short to earth/chassis.

filmguy
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#11 erstellt: 18. Apr 2005, 16:40

thats very helpful and informative ravi.

quote]
So might be worthwhile checking for damaged earth wiring on west side or faulty equipment with a short to earth/chassis.
[/quote]

how can i do that ravi ??

ravi
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#12 erstellt: 22. Apr 2005, 16:40

filmguy, one of the the main suspects is your amp itself - is this using a 3-pin plug? Which amp us this? Does the same problem occur when you connect the RCA to other equipment using 3-pin/2-pin plug?
If you can lay your hands on a multimeter, or a good elecctrician, get the voltages between all the mains terminal measured and see if the earth voltage is proper ( <5V w.r.t neutral and 220V w.r.t live) - with the amp connected

ravi
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#13 erstellt: 22. Apr 2005, 16:42

PS: take the problem seriously and get it resolved, since I blew both my sub and the sub channel on my AVR due to some earthing goofup not very long ago