B&K Ref 200.2- Hiss
Jer.War
Posts: 180
Hello all,
I am hoping some of the more tech savy members can maybe help me shed some light on an issue with my B&K Ref 200.2 power amplifier. For the last little while I have noticed that when I first power on the amplifier there is an audible hiss from the left channel. There is no hum at all, the hiss sounds like static and is most audible from the tweeter. Initially the hiss is audible from a foot or two away, but it usually quited down after sevral hours of the amp being on. The right channel is dead quiet all the time.
I have switched out ICs, but the hiss remains. If I swap the channels the speaker cables are connected two, the hiss moves to the right channel. The hiss is present no matter what input is selected on the AVR (I have also tried connected the amp directly to the variable ouputs on my CD player with the same result). When the hiss "settles" it is only audible when within 4 inches or so from the speaker (though probably twice as load as the other channel).
Recently I went out of town for sevral days and disconnected all electroncis from the wall. Upon coming home and firing up the system, the hiss was audible from 6 feet away from the left channel while the right channel remaining unchanged. After 10 hours of being on, the hiss has quieted to the point where it is auidble from 2-3 feet away.
What section of the amplifier would cause these types of symtoms. I am a newly graduated electronics technologist and have knowledge of electronic components, test equipment, and definately know my way around a soldering iron. I am hoping there are some likely suspects that I can change out. Where should I start looking (power supply section, output, etc), and how should I go about it. I am hoping I can email B&K and snag a service manual, or at the very least a schematic.
Any insight would be greatly appreciated.
Thanks guys,
Jeremy W.
I am hoping some of the more tech savy members can maybe help me shed some light on an issue with my B&K Ref 200.2 power amplifier. For the last little while I have noticed that when I first power on the amplifier there is an audible hiss from the left channel. There is no hum at all, the hiss sounds like static and is most audible from the tweeter. Initially the hiss is audible from a foot or two away, but it usually quited down after sevral hours of the amp being on. The right channel is dead quiet all the time.
I have switched out ICs, but the hiss remains. If I swap the channels the speaker cables are connected two, the hiss moves to the right channel. The hiss is present no matter what input is selected on the AVR (I have also tried connected the amp directly to the variable ouputs on my CD player with the same result). When the hiss "settles" it is only audible when within 4 inches or so from the speaker (though probably twice as load as the other channel).
Recently I went out of town for sevral days and disconnected all electroncis from the wall. Upon coming home and firing up the system, the hiss was audible from 6 feet away from the left channel while the right channel remaining unchanged. After 10 hours of being on, the hiss has quieted to the point where it is auidble from 2-3 feet away.
What section of the amplifier would cause these types of symtoms. I am a newly graduated electronics technologist and have knowledge of electronic components, test equipment, and definately know my way around a soldering iron. I am hoping there are some likely suspects that I can change out. Where should I start looking (power supply section, output, etc), and how should I go about it. I am hoping I can email B&K and snag a service manual, or at the very least a schematic.
Any insight would be greatly appreciated.
Thanks guys,
Jeremy W.
[The Ever-Evolving System
LSI15's (PNF Symphony cabels, modded X-Over and subs), LSIC, LSI7's, Rega Apollo CDP (PNF ICON ICs, modified PS cct.), Yamaha RXV-1700 w/ ipod dock, B&K REF200.2 (fronts) Samsung BDP-1600, XBOX360, Patriot Box Office Media Player, 42" Samsung LCD.
Post edited by Jer.War on
Comments
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If it is only in one channel I would look at the output side of that channel. Probably a cap getting old. Look for any swollen caps.
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Yep, caps that are old or worn will start to hiss and eventually they might start to pop and click. Had that problem with a 25 year old Nak pre-amp. The tech replaced two small caps at the cost of $128. The caps cost about $8 the rest was labor and cleaning supplies, etc.
Do you have a schematic for the amp? I wouldn't attempt anything before studying the schematic.
H9"Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
