Vistas humming :(

[tomi]

Hello everyone

I bought a pari of ML Vistas a couple of months ago. The problem is that one of them is giving quite irritating hum from its stator(the hum starts when the blue led lights). I've switched them between and it seems that it is only one of the Vistas which is humming. Although I unplugged speaker cables from it, the hum still remains. Only after unplugging the power cord the stator is silent, of course. I have tried to lead power through a conditioner or directly from a wall socket and tried to use a very expensive power cable, too. But no effect, the hum still exists. I don't know what to do, so any ideas? Could it be that some component or plug is abit loose inside the speaker?

 

[zaphod]

I don't know what to do, so any ideas? Could it be that some component or plug is abit loose inside the speaker?

well... with any kind of hum i wonder about ground loop. is this a 60Hz hum? is this a mechanical hum/rattle - or are the panels producing the hum?

can you put a ground lift into the mix to see if that gets rid of the hum? do you have a coax cable feed? cable is notorious for being poorly grounding creating an imbalance and hum, so disconnect the cable feed that pops into the house and see if that gets rid of the hum.

i once had a hum on the rears (particularily the left rear) and it was traced down to the VCR and television having an imbalance on the cable feed. when the two where both attached to cable, hum happened. an isolation transformer on the cable feed fixed it up.

at the office, i have my PC plugged into my system and it creates hum on all channels like a man with no words. i dropped in a ratshack ground loop isolater 1/8mini to RCA cable (part #2700054) and the problem went away.

hum. ground loop. bad.

 

[VanDaRo]

I once suffered this issue once when I lived in Hawaii. Traced it down to the power amps and a ground loop noise courtesy of a dimmer switch controlling an array of spotlights in the listening room. When I cheated the ground prongs on the amps, the noise went away -- but that seemed to be an unsatisfactory (unsafe) answer. So I removed the spotlights and dimmer switch.

Hope your issue is as simple

~VDR

 

[twich54]

ground loop noise courtesy of a dimmer switch controlling an array of spotlights in the listening room.

Van, this is part of which I preach about NOT having any of our audio equipment wired to one of the legs in your service panel that has 'noise making' devices on it, Dimmer swithces, ceiling fans, and anything with a compressor are all culprits !

Tomi, first off ...welcome ! as for your situation I'll plead somewhat ignorant....is Finland 220v / 50hz ?? If so I don't know wiring codes, etc for your neck of the woods and how they related to 'ground loops' but the fact that it is only with the one speaker I'm suspecting some kind of parasetic / short issue with it ????

 

[amey01]

The Vistas don't have an earth connection (or at least mine don't). That would mean the hum is coming from your amp, or is a problem with the speakers. Disconnect the amp and see if the hum goes away (ie. Pull the speaker leads out but leave the power connected).

 

[Feltran]

Try vacuuming, and make sure there is nothing like a WiFi router or microwave within a couple feet of the speaker. (Please, please tell me you don't have a microwave sitting on top of your speaker cabinet! )

 

[tomi]

No, I don't have a microwave sitting atop of my speaker cabinet

And yes, I think it is a 60Hz hum... Don't have any coax cables or other digital cables in my system(driving Vistas with Pathos ClassicOne mk III tube/hybrid amp).

I tried vacuuming the Vistas, but it was useless. Couple of hours ago I also tightened all the screws and connector plugs inside the problem speaker, but again the hum is still there.


twich54: We have 230V/50Hz here in Finland. It was 220V about twenty years ago.

amey01: I tried to leave only the power cable connected. However, the speaker is still humming. Disconnecting the speaker cables have no effect on it.

 

[ScottGardner]

This kind of problem can be caused by a failing capacitor.

You should call, or send an email to, Jim Power at Martin Logan

[email protected]

He is usually very helpful.

 

[FISH_MAN]

when do we get to see your system scott gardner ?

 

[amey01]

Yep, well it's a problem with the speaker. Call Jim - you're probably going to have to replace a HV board.

 

[ScottGardner]

when do we get to see your system scott gardner ?

I just put up more pictures in the 'How much can a computer do' thread that shows everything from way old to now.

http://67.19.167.226/~tdacquis/forum/showthread.php?t=7342

 

[tomi]

Thanks! I'll contact Jim.

 

[twich54]

And yes, I think it is a 60Hz hum...



twich54: We have 230V/50Hz here in Finland. It was 220V about twenty years ago.

.

OK.....so then.... if you have 230v/50hz how does one have a 60hz hum ??

 

[tomi]

Mission accomplished!

No humming anymore, whether it was 50 or 60Hz hum

Jim advised me to flip the HV board 180 degrees because mains transformer was maybe too close to the crossover inductor. Something to do with magnetism?

In addition, I checked out the other speaker and surprise, surprise, it is now completely silent, too.

 

[amey01]

Mission accomplished!

No humming anymore, whether it was 50 or 60Hz hum

Jim advised me to flip the HV board 180 degrees because mains transformer was maybe too close to the crossover inductor. Something to do with magnetism?

In addition, I checked out the other speaker and surprise, surprise, it is now completely silent, too.

What do you mean by "flip the HV board 180 degrees"?

 

[tomi]

It means to remove the four screws holding HV power supply and then to turn the board 180 degrees clockwise. At least the instructions Jim sent me told so