humming noise from Krell 300iL

[jseog]

Hi,

I brouhgt Krell 300iL 9 months ago.
Recently I noticed that humming noise is coming from the unit.
I checked a few things and it was clear that the noise is coming from the unit as soon as it is plugged in.

If you experienced similar problem and can let me know how to solve this problem, I would greatly appreciate your help.

Joonil

[joel2762]

Well, I don't own one so I can't give real advice. But is it so loud that it's an annoyance? It could be just the normal operation of the power supply but not if it's too loud.

[jseog]

Thank you for your reply.
Actually, it is not that loud. I was just afraid that it might lead to other problems. It may be normal. I will just keep an eye on it to see if it gets any louder.

Thanks,

Well, I don't own one so I can't give real advice. But is it so loud that it's an annoyance? It could be just the normal operation of the power supply but not if it's too loud.

[StanleyMuso]

and it's still performing faultlessly. Mind you, its not a Krell.

I read somewhere that most tranformers hum and that its got something to do with them vibrating at the frequency of the electricity supply. I'm not an electronics person, so cannot really explain, perhaps someone else on this forum could.

At any rate, I can only hear it if its very quiet and nothing is playing, and from close up. So if yours is behaving in similar fashion, I would expect that you have nothing to worry about.

Oh, just remembered something else - I was told long ago that high power amps, with their powerful transformers, tend to produce more noise than lower powered amps.

[topspeed]

1) If at all possible, don't plug your amp into the same circuit as the rest of your equipment (unless you're using a power conditioner). In other words, if you have it plugged directly into a wall recepticle make sure the other equipment isn't in the other plug on the plate. In an ideal world, you would plug your sources into a separate circuit all together.

2) If your amp has a grounded plug (3 prong) check to make sure your house ground is good and strong. If that's not practical, go buy a cheater plug (a 2 prong adapter for your power cord) for .75 cents or remove the ground off your power cord if it allows you to do so.

3) If you're into such things, try an aftermarket power cord such as a PS Audio XStream or Cardas Golden Reference which have some filtering capabilities designed into them. They may take the hum away but buyer beware, it's completely up to you to decide if they make a noticeable improvement in sound.

4) As mentioned, it could just be the status quo for your amp. Some amps hum. If, however your are hearing it from your listening position I'd say it's more than that.

Good luck and let us know how it works out.

[Hairsonfire]

Big amps tend to hum. I have two Aragon 8008BB's and when the do hum, both at the same time - even the same pitch! It appears to be an idiosyncratic anomalie with big power supplies and non-dedicated circuit. No worries mate!

[jseog]

Thank you for all your comments.

I tried 1 and 2 but it did not make a difference. I can hear this humming noise when the room is very quite and I am very close to it. Now I suspect the voltage stability might cause a problem but I have not checked it yet. I heard that there is a voltage stabilizer that maintains 120V. If it get rid of the humming, I will let you know.

Thanks again

Joonil

1) If at all possible, don't plug your amp into the same circuit as the rest of your equipment (unless you're using a power conditioner). In other words, if you have it plugged directly into a wall recepticle make sure the other equipment isn't in the other plug on the plate. In an ideal world, you would plug your sources into a separate circuit all together.

2) If your amp has a grounded plug (3 prong) check to make sure your house ground is good and strong. If that's not practical, go buy a cheater plug (a 2 prong adapter for your power cord) for .75 cents or remove the ground off your power cord if it allows you to do so.

3) If you're into such things, try an aftermarket power cord such as a PS Audio XStream or Cardas Golden Reference which have some filtering capabilities designed into them. They may take the hum away but buyer beware, it's completely up to you to decide if they make a noticeable improvement in sound.

4) As mentioned, it could just be the status quo for your amp. Some amps hum. If, however your are hearing it from your listening position I'd say it's more than that.

Good luck and let us know how it works out.

[mtrycraft]

3) If you're into such things, try an aftermarket power cord such as a PS Audio XStream or Cardas Golden Reference which have some filtering capabilities designed into them. They may take the hum away but buyer beware, it's completely up to you to decide if they make a noticeable improvement in sound.

Good luck and let us know how it works out.

How would this minimize hum? Power cord just cannot do this, regardless of their claim to marketing fame.

[mtrycraft]

Hi,

I brouhgt Krell 300iL 9 months ago.
Recently I noticed that humming noise is coming from the unit.
I checked a few things and it was clear that the noise is coming from the unit as soon as it is plugged in.

If you experienced similar problem and can let me know how to solve this problem, I would greatly appreciate your help.

Joonil

Have you called Krell? Since they designed it, they should know what hum it should or should not have. I bet it is either some parts that resonate to the transformer, or the transformer itself is causing audible hum either through its plates or interacting with other parts.

[mtrycraft]

An after market power cord is not the answer. It is an audio voodoo product.

[Kursun]

Hi,

I brouhgt Krell 300iL 9 months ago.
Recently I noticed that humming noise is coming from the unit.
I checked a few things and it was clear that the noise is coming from the unit as soon as it is plugged in.

If you experienced similar problem and can let me know how to solve this problem, I would greatly appreciate your help.

Joonil

It's a case of mechanical hum from the power transformer. This usually occurs in sub-standart components, mostly NAD and some other British stuff. I didn't ever hear a Japanese equipment humming, not even the power transformers of Technics amplifiers.

I had read somewhere that Yves Bernard André of YBA dips their power transformers in shellac for 24 hours, so that their iron laminations don't have any hairline gaps.

A power conditioner or regulator won't fix the problem. But if you change the frequency of the line frequency the transformer's laminations may stop resonating. But this solution is of course not practical. One solution would be inserting an isolation material between the transformer and the chassis and tighten the nuts.

[jseog]

Thank you for all of your comments.
I recognized the humming sound is sometimes there and sometimes isn't.
I agree that something got loosened near transformer.
I would be dissapointed if Krell used cheap transformer in their expensive amp.

When this noise starts to really bug me, I will send it to the factory.

Thanks for your help.

Joonil

[mtrycraft]

Thank you for all of your comments.
I recognized the humming sound is sometimes there and sometimes isn't.
I agree that something got loosened near transformer.
I would be dissapointed if Krell used cheap transformer in their expensive amp.

When this noise starts to really bug me, I will send it to the factory.

Thanks for your help.

Joonil

Even Toyota may have a few lemons, from time to time

[sldg]

Hi Joonil

If you purchased this unit new why wait until it gets worse or becomes a problem? I'm sure you payed good money for this amp, get it fixed. Krell should have no problem making you happy. If they don't let me know. I live about 5 minutes from the factory and woundn't have a problem giving Dan D'Agastino a piece of your mind in person! At least call them and let us know how you make out.

sldg

[jbangelfish]

Don't know if you ever solved your humming problem but there can be many causes to an audible hum in an amp. I have two identical Parasound amps, one hums and the other does not. The Parasound owners manual gives a list of suggestions to eliminate hum and they refer to it as a 60hz or 50hz hum depending on what part of the world you live in. In other words, it's a common problem associated with household current. The first suggestion is to reverse the plugs of each other component in the system, one by one to see if this eliminates the hum. If this does not work, they suggest that you reverse the way that the power amp plugs into the outlet. Being grounded plugs, they tell you to get an adaptor and eliminate use of the grounding plug but I'm not fond of this idea. I let mine hum and don't worry about it, the hum is minimal.
I get a hum through the speakers if I leave a certain florescent light on in the next room.This seems to just be some interference probably from the same circuit and is most likely not the type of hum that you are talking about. If I ever finish my stereo room, each amp will have it's own dedicated circuit and hopefully will alleviate my problems.
Anyway, my 2c worth related to amp hum.
Bill