Hi All!
I've got a problem with my hifi. My system is an actively biamped 3-way system. I use an integrated amp (NAD C370). Its pre-amp part leads to a Behringer cx 3400 crossover. From there the mids and highs go to the poweramp part of the NAD, the low end goes to a JB Systems AX400 poweramp.
The system has always worked fine. Yesterday I discoverd a strange kind of noise from the midrange driver of the left speaker. The noise is not loud, but audible when about 1 meter from the speaker (about 3.3 feet). It sounds like a beep, with some kind of cracks in it, and the frequencie constantly changes but with small steps. Guess the frequencies are somewhere between 500 and 800 hz.
I tried a few things to find out what causes this noise. I switched powerams (used the NAD to drive the lows, the JB Systems to drive mid/high), now the noise came from the woofers.
Switched cables that go from Crossover to both poweramps, but these were also not at fault.
Tried the NAD used as a complete integrated amp on my dads B&W CDM 9 NT (with passive crossovers): No noise.
The noise is still there when the Behringer is turned off. Strangely it disappears when I pull the powercord out of the behringer!
What could cause this noise? Is there something wrong with the NAD?
I've got a problem with my hifi. My system is an actively biamped 3-way system. I use an integrated amp (NAD C370). Its pre-amp part leads to a Behringer cx 3400 crossover. From there the mids and highs go to the poweramp part of the NAD, the low end goes to a JB Systems AX400 poweramp.
The system has always worked fine. Yesterday I discoverd a strange kind of noise from the midrange driver of the left speaker. The noise is not loud, but audible when about 1 meter from the speaker (about 3.3 feet). It sounds like a beep, with some kind of cracks in it, and the frequencie constantly changes but with small steps. Guess the frequencies are somewhere between 500 and 800 hz.
I tried a few things to find out what causes this noise. I switched powerams (used the NAD to drive the lows, the JB Systems to drive mid/high), now the noise came from the woofers.
Switched cables that go from Crossover to both poweramps, but these were also not at fault.
Tried the NAD used as a complete integrated amp on my dads B&W CDM 9 NT (with passive crossovers): No noise.
The noise is still there when the Behringer is turned off. Strangely it disappears when I pull the powercord out of the behringer!
What could cause this noise? Is there something wrong with the NAD?
Hi Pinkmouse,
I just found out something very strange!
the powersockets in my listeningroom have no earthings. The Behringer unit does have a powerconnector with earthingpoint. I ran a wire from the nearest earthingpoint in the house to the case of the behringer, and when the wire end got very near the case I could see current sparking over! So there must be voltage on the case. Is this normal?
I was thinking, maybe the two other poweramps I used to compare to the NAD had better DC blockers (they are PRO amps)?
keyser
I just found out something very strange!
the powersockets in my listeningroom have no earthings. The Behringer unit does have a powerconnector with earthingpoint. I ran a wire from the nearest earthingpoint in the house to the case of the behringer, and when the wire end got very near the case I could see current sparking over! So there must be voltage on the case. Is this normal?
I was thinking, maybe the two other poweramps I used to compare to the NAD had better DC blockers (they are PRO amps)?
keyser
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