Again, need to know if this problem exists with short cables, and exactly how they are constructed.
There are two types of shield: Braided and foil. Foil is 100% coverage, braided around 80% I believe.
All my cables are 2 conductors plus shield, never have a noise pick up problem.
Best,
Erik
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It is
Done by licensed electrician |
jricci Would running cables through a braided sheild in the conduit work? Before undertaking additional work, you should try correcting your improper electrical safety ground that is "
independent from rest of house
" and be sure that it is properly bonded to the neutral bus bar in your electric service panel. |
If you read some of my prior posts on hum you will learn I had what seems to be a similar problem on my phono source. I wrapped my tonearm cables in aluminum foil and that took care of the problem. I think they were picking up hum from my Audio Valve Baldur 300 monobloc transformers. Tom. |
My system Frankensteins and coincident phono stage are unbalanced
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Would running cables through a braided sheild in the conduit work?
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Try shielded cables for your phono connections. That's what I use and they are dead quiet |
Jricci,
But it doesn't happen if you use a short cable?
Erik
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The noise occurs if interconnect connected to amplifier
Doesn't matter if
-connected to phono amp
-phono amp on or off
-phonoamp volume up or down
-phono or bypass input selected
|
I just noticed that the Coincident statement line stage does in fact include balanced outputs built in.
One last thing, running audio cables in metal conduits can roll off the highs due to capacitive coupling.
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@reubent Check out my blog post on ground loops. :) Cable TV often causes that. http://pqltd.blogspot.com/2016/11/quick-safe-and-easy-fixes-for-ground.htmlJricci, Let’s assume it really is EMI/RFI that you are hearing, and not a ground loop issue. With RCA lines running that long it could be an issue and may not be solvable with just cables. Make sure your cable is 2 conductors + shield. Connect the shield and - side at the preamp side only. This may not fix the problem, in which case your choices include: - Converting the signal to balanced/XLR outputs and run that XLR to amps that accept XLR. (this can also be done with matching transformers at both ends)
- Moving the preamp and amplifiers so they are much closer together.
Also, before you do any of this, make 100% sure you don't have significant noise pick up in the preamp itself. I've seen cases where this occured as a result of being too close to a transmitting station. Best, Erik |
jricci,
Does it only make the noise when you have the phono input selected, or is it when any input is selected? I ask because I just remembered that my system has a nasty noise when the phono is selected and I turn on the TV. Not sure what is causing it, but I just turn off the TV and it goes away. I don't know if the cable or the cartridge are picking up the interference. Regardless, turning off the TV resolves the issue. No other inputs are affected, just phono. |
jricci Separate audio system ground independent of house ground
All audio grounds share single ground with no ground loops
To what is your audio system grounded? Again, all electrical grounds should be bonded to the neutral in your service panel, per NEC. |
Not directional
Happens with any audio cable |
Separate audio system ground independent of house ground
All audio grounds share single ground with no ground loops
Noise present when interconnect connected to amplifier input. No other connection impacts sound. No effect of phono amp gain or power on |
I don't know the topology of your cable, but you could try swapping it end for end (turn it around). Some cables are grounded on one end only. It's probably a longshot, but I don't think it would hurt to try it. |
I have a coincident
phono amplifier and biamped coincident speakers with dedicated 20 A
circuits from a separate panel share a common star ground (independent
from rest of house).
There is not ground hum, but when phono to amplifier interconnects connected to amplifiers a course EMF like noise occurs.
It isn't clear what you mean by "
course EMF like noise
." But the problem could be your ground, which you state is not shared with the rest of your house. In the US, this would be a violation of the NEC and is potentially hazardous. In any event, if it's an unshared ground ... to what is your system grounded? It sounds like it's not bonded to the neutral in your service panel, which would tie it back to the electric utility ground. That's your best ground, which of course is supplemented with ground rods as required by code. |
