Metro gets all the credit. All I did was to describe how to use the meter.
Glad the mystery is solved!
Regards,
-- Al
Glad the mystery is solved!
Regards,
-- Al
Strangest problem I've ever had
I found this thread interesting to read. Riasillo, I do have a few questions, curiosity I guess..... On way to get a meter to test wires.Electrician did his job? What all did the electrician do? New branch circuits? How many? Extend from existing wiring only? Type of wiring used? NM-B, Romex? Conduit and wire? How did the electrical pass through the studs? Please be specific as possible.
"plugged into different outlets with nothing else attached, volume on zero = very loud buzz... very loud..." Outlets on the same 120V circuit? Outlets on different 120V circuits?
Are the wall studs metal? A drywall screw through the jacket of the speaker cable and piercing the red conductor wire would indeed bond the wire to the metal stud. Assuming the electrical receptacle outlet box/es are metal this would bond the safety equipment branch circuit/s equipment grounding conductor to the metal studs. Thus the shorted reading you got with your meter. live and learn, should have hired a better low voltage guy that properly protected the wires in the wall... I didn't like the way he left them exposed around studs... I should have covered them with some cheap metal strike plates...or he should have..Holes for cables, wires, that pass through studs should be back from the surface of the studs 1 3/4" to protect the cable from physical damage from a drywall screw. Where studs are notched or the holes for cables are less than 1 3/4" from the surface a steel plate of at least 1/16" shall cover cable, wire, to protect the cable from damage of a drywall screw. Cables, wires, that pass through holes in metal studs shall be protected from damage by bushings or the like.
That still puzzles me...... Output of a power amp ya.... Damage a separate connected preamp? Maybe Al could expand on that..... One thing for sure I would not connect any new equipment up until everything including the electrical power is checked out. At the very least pick up one of these and check each receptacle for correct wiring and proper AC polarity. Jim |
Damage a separate connected preamp? Maybe Al could expand on that.....Hi Jim, Assuming that both components have 3-prong power plugs, as you realize the short would result in a direct connection from the "hot" output terminal of the amp to the chassis of both components. What happens from there is obviously hard to predict without knowing the details of the grounding configurations of the components, and other aspects of their design. But depending on the impedances between the chassis of each component and their circuit grounds, some fraction of the current flowing from the amps hot output terminal will find its way back to the amps circuit ground via the Onkyo receiver (being used as a preamp) and the return conductors of the cables connecting the two components. One conceivable scenario would therefore seem to be that a feedback loop is created from the amplifier's output to some upstream circuit point or points, via the Onkyo's grounds, resulting in a large amplitude oscillation, resulting in damage to circuitry in the Onkyo that is designed to handle low level signals. Or something like that :-) Best regards, -- Al |
To add more fun, and headaches to it, it sounds like Quietrock 530 has metal inside it. It's under "cutting the panel" on page one. I saw this on a home improvement type of TV show. |
jea 48. low voltage guy passed wires around studs in the front between drywall. I questioned it, not knowing any better and he said it was fine because the drywall guys could see it and work around it. Hard lesson learned. also cost me a perfectly good receiver. The electrician came in after, ran electric from existing bank of outlets to spot above fireplace for recessed outlet. His wiring went through studs and was to code as best I can tell... thick yellow wire, that's all I can tell you. I also had everything plugged into APC line conditioner/surge protector. Drilled hole today to outside of house, poked wire through and ran it under edge of house out of site, came back in where the cable wire comes. Problem solved ghetto style, I now have a left speaker run... just cost me a $10 for a masonry bit. Hooked up speakers to onkyo direct, drives them fine... pre outs still shot. Now i'm off to get a new receiver...what to buy, what to buy... I was planning on plugging receiver into amp with nothing connected to receiver. fingers crossed when i plug into AMP that the B&K is fine and there is no buzz... then i will connect cable box to receiver and hopefully speakers sign again... any suggestions on way to test amp other than that? I actually have a little Ipod 1/8jack to RCA adapter. I could plug that into amp and see if amp works right? |