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Hummm in each speaker

krazyjohnny, modified 12 Years ago.

Hummm in each speaker

Youngling Posts: 7 Join Date: 1/4/11 Recent Posts
Genelec gurus I need your help.

I just got a complete new home theater system for Christmas and it included the Genelec 8020 Espresso 5.1 system. I have a hum in every speaker. I am using the Denon 3311ci reciever and the speakers are connected to it via the pre-amp outputs which are RCA. The cables being used are RG-6 Coax with RCA connectors on both ends. I am using an RCA to XLR adapter to go into each monitor. What do I need to do to eliminate the hum?

Also is there anyway to power these off when the system goes off. All of my previously owned powered subs had a signal register that would turn off the power to the sub when there was no signal.

By the way these things are awesome!
krazyjohnny, modified 12 Years ago.

Re: Hummm in each speaker

Youngling Posts: 7 Join Date: 1/4/11 Recent Posts
No response in 24 hrs. I have actually purchased and installed the equipment in my home. If this is not the place to answer my question or seek advice please direct me to the proper location. I searched the FAQs and did not find the answer there. :?:
krazyjohnny, modified 12 Years ago.

Re: Hummm in each speaker

Youngling Posts: 7 Join Date: 1/4/11 Recent Posts
Did some more digging around and found this:

http://www.genelecusa.com/ht/learning-c ... d-outputs/

It appears that if post 1 and 3 are connected that should solve the proble on an unbalanced connection?

Please confirm.
krazyjohnny, modified 12 Years ago.

Re: Hummm in each speaker

Youngling Posts: 7 Join Date: 1/4/11 Recent Posts
I got home tonight and got into the RCA to XLR adapters I am using. There is a soldered connection from the metal housing on the adapter to the #3 pin and then the #3 pin has a connection made between it and the #1 pin. The outer part of the RCA connector makes contact via a tab to the metal housing on the adapter. Is there something wrong with this set up?

Anyone? Throw me a bone here or something. I would really like to get this figured out.
andreas, modified 12 Years ago.

Re: Hummm in each speaker

Padawan Posts: 61 Join Date: 4/8/09 Recent Posts
If the adapters are from a brand, then we we can assume they are soldered correctly. What you say with Pin 1 and 3 sounds right.

Hum in all speakers is often more likely to come from something like a satelite receiver or some ground loop in the chain. You can try to buy a filter then for the antenna cable. Really check component for component. Start with just a CD player and the Denon, disconnect the rest. Is there also hum, if just these two are connected to the Genelecs ?
andreas, modified 12 Years ago.

Re: Hummm in each speaker

Padawan Posts: 61 Join Date: 4/8/09 Recent Posts
No response in 24 hrs


One more hint. 6th, if I'm not mistaken, is holiday in Finland as well. It can mean that starting yesterday or earlier Genelec staff is not in the forum that often taking bridge days as well. At least that is what I would do....hehe...so be patient, latest Friday or next week they will reply as well ;)
krazyjohnny, modified 12 Years ago.

Re: Hummm in each speaker

Youngling Posts: 7 Join Date: 1/4/11 Recent Posts
There is a hum no matter what is on. You can only hear it when there is no signal being sent to the speaker. If there is signal being sent then it is enough that you cannot hear the hum.

Sorry about the impatience, but I had seen posts answered in other forums multiple times while mine was ignored. Hope everyone has a great holiday in Finland.
andreas, modified 12 Years ago.

Re: Hummm in each speaker

Padawan Posts: 61 Join Date: 4/8/09 Recent Posts
Yes, as said, it must be a ground loop then. What is connected to the Denon ? Can you exchange the RC6 cables for others with RCA plugs ?

What you can do, but this is not recommended at all, you can tape the ground pin on the power plugs of the Genelecs with isolation tape as a test. I once had a ground loop from a poor power socket in the back wall of my room....

When you take a different source (no 110/230 Volts source), what happens ? Take an MP3 player or your mobile phone and play an MP3 song that directly into your Genelec speakers, do you also get a hum ? Of course wou would need to have a cable from 3,5mm phone jack to RCA.....or try a different room, different power sockets....

There is a hum no matter what is on.


Do the speakers hum already when you have nothing connected to them ?
krazyjohnny, modified 12 Years ago.

Re: Hummm in each speaker

Youngling Posts: 7 Join Date: 1/4/11 Recent Posts
There is no hum if I disconnect the RCA cable from the adapter and leave the speaker plugged in and on. As soon as I disconnect the input cable the hum is gone.

The RG-6 quad shield Coax has RCA ends on it both at the speaker and at the Denon pre-amp out end. If I push the adapter to one side or the other while attached to the speaker the hum almost goes away.

I have also ran a ground lead from the ground on the back of the Denon 3311 to the Panamax 5100 grounding post to hopefully help. It did not. I did this because the Denon is only a 2 prong power plug with no ground.

All of the equipment is on a completely separate circuit from the speakers. The speakers have their own circuit and breaker in the power distribution panel for the house.
andreas, modified 12 Years ago.

Re: Hummm in each speaker

Padawan Posts: 61 Join Date: 4/8/09 Recent Posts
The speakers have their own circuit and breaker in the power distribution panel for the house.


That does not matter. The gain on the shield wire is comming from what is connected to the Denon. Is the hum also there with nothing connected to the Denon ? (disconnect all wires on the Denon besides voltage)

A test is so easy. Connect an MP3 player with volume control to the speakers without the Denon. I'm sure you pick up gain on the shield/ground of the RCA plugs via one of the sources connected to the Denon.
krazyjohnny, modified 12 Years ago.

Re: Hummm in each speaker

Youngling Posts: 7 Join Date: 1/4/11 Recent Posts
Andreas,

Found the issue. It comes from me having to hire the magnolia guys to do the install instead of me doing it myself.

They had plugged the Denon into the Panamax 5100 on the same bay as some of the equipment. It should have been connected in its own bay on the Panamax and then the Blu-ray, CD player, Control 4, etc should have been plugged into their own respective bays as indicated on the back of the Panamax. The Panamax 5100 is designed to eliminate this very issue and it seems to do its job exactly as specified.

Thank you for you insight and help.

Now to find out if it is OK to leave the Genelecs on all of the time?
andreas, modified 12 Years ago.

Re: Hummm in each speaker

Padawan Posts: 61 Join Date: 4/8/09 Recent Posts
Hi KJ,

glad you found it out. For usre a relief for you. Enjoy.

Now to find out, if it is OK to leave the Genelecs on all of the time?


That we leave to Illka to confirm :-) There probably is a MTBF value available for the 8000 series. I think they are designed to stay on, if really necessary, as most Genelec speakers are also availalbe/sold for fixed installments in venues or professional installs/exibitions/displays, where speakers may need to stay one all the time.....
ilkka-rissanen, modified 12 Years ago.

Re: Hummm in each speaker

Yoda Posts: 2564 Join Date: 3/23/09 Recent Posts
There is a hum no matter what is on. You can only hear it when there is no signal being sent to the speaker. If there is signal being sent then it is enough that you cannot hear the hum.

Sorry about the impatience, but I had seen posts answered in other forums multiple times while mine was ignored. Hope everyone has a great holiday in Finland.

Hi,

It's not that I would have ignored your question, it's just that I didn't have a clear answer/solution to your problem and therefore needed some more time to figure out the possible cause. Also Epiphany on the 6th caused some additional delay. I'm terribly sorry for this.

In any case I was happy to find out that you (with the great help of Andreas) were able to figure out the problem by yourself! :)