2. amps-preamps
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Krell Service - speakers buzzing

I recently started experiencing a buzz in both my main speakers, After lots of troubleshooting, I believe the issue is my pre-amp. When the pre-amp is on or off/stand-by, the buzz is there. When actually unplugged, the buzz goes away. It is a Krell KAV-250p. I bought it used in 2013. My questions:

1. Why is it causing buzzing? I am more curious than anything.

2. Is there any point in trying to replace the cables between the preamp and amp (XLR type)? When I unhooked them the buzzing went away, presumably because there was no longer a connection between the pre-amp and amp. My assumption was since both speakers are buzzing, that is not the answer.

3. If you all think the pre-amp is the issue (and there is nothing else I should try in terms of troubleshooting), can it be serviced? Is it worth servicing? I like it. On the other hand, always fun to upgrade a piece of equipment, except everyone tells me the KAV-250p is a good unit.

Let me know if there are any other details I can provide. Thank you.

 

Jeffrey

olfac87

Showing 2 responses by mlsstl

mlsstl
1,395 posts
 

A simple alternative is to borrow a different preamp (or use the preamp output of an integrated amp) and see if the hum is still there. 

If the hum disappears with the other preamp, this indicates the Krell needs servicing. If the hum is still present with the other unit then you need to look elsewhere in your house for the cause, as Erik described.

I noted this particular Krell unit was released around 1997 so your unit could be up to 27 years old. Its not uncommon for the power supply capacitors to need replacement at this point, but there are also other things that might need fixing.

mlsstl
1,395 posts
 

"Throw a cheater plug on your preamp..."

That's a good experiment to try when you have a hum problem the first time you use a new piece of equipment or install it to a new location or setup, but my understanding of the OP's issue is that the preamp had been working just fine for the past ten years and only recently started buzzing.  That reduces the likelyhood of a ground loop issue and increases the odds that its an equipment aging problem.

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