Where is the sound of silence?

Auralsaga

Standard Member
Hi folks,

I'm getting the classic low level hum coming from my power amplifier and now it has started coming from my speakers (at a very low level). All cables are good quality and shielded where they need to be. I also have an IFI Purifier and an Audiolab DC Blocker which plug into two separate extension blocks simply as I only have two wall plugs that I can use within reach.

The hums are not volume dependent and I hear them with no volume, but on standby it's doing my head in. None of this occurred until I added the power amp.

Due to the positioning of my hifi rack (in the only place it can go as I have a large fireplace in-between the speakers), many cables do run in parallel although I do my best to keep speaker cables away from power cables.

I also have a student multiple occupancy flat through the wall and they i'm sure will be streaming multiple devices etc. etc. The flat is also old so the wiring may not be amazing.

Does anyone have any practical solutions (apart from move house)? Any info would be greatly appreciated.

I read that I can ground the chassis of the power amp but have no idea how to and I know it may actually be an issue with the transformer in the used amp itself.

Really weird that the speakers have started humming now without changing anything else. I never have them over about 1/5th volume, so i've not blown them and they can handle 120W. Plus i've no young uns who could've been playing with the hifi when i'm out!

Cheers,
A
 

Helix Hifi

Well-known Member
It could be earth hum. There is nice vide by Paul PS Audio online. He’s suggestion is to disconnect every source and eliminate so to speak this component. If the hum is still present them I am afraid there is fault with power amplifier.

Perhaps I am misunderstanding but all of the components are connected to one power strip? This is must. Can you try another power strip?

I had an annoying back in the day. Nothing worked, just had to disconnect the component. Voila silence. This was hum from the speakers. Amplifier hum is very, very annoying. This is usually the transformer or the chassis.

By tightening the transformer this could work. I am no expert, so probably other people could help. I seem to read all component have different earth hum measurements this is why you need to use one power strip only
 

Auralsaga

Standard Member
Hi, thanks Helix. I have to use two power strips. One for the AV stuff and one for the hifi stuff as I only have two wall sockets that are within reach. I have blockers on each of them. Longest wall has a large fireplace on it (tv above) and opposite is the sofa and my listening position. The short ends of the room have another sofa and the other a work table, so not alot of room to maneuver.
 

Helix Hifi

Well-known Member
The hum in my situation was cheap Fiijo DAC. But some kit just hum. Like my old Rega Dac R. It had an annoying hum. Got rid of Dac.
Hi, thanks Helix. I have to use two power strips. One for the AV stuff and one for the hifi stuff as I only have two wall sockets that are within reach. I have blockers on each of them. Longest wall has a large fireplace on it (tv above) and opposite is the sofa and my listening position. The short ends of the room have another sofa and the other a work table, so not alot of room to maneuver.
I see. The hum occurs with new power amplifier. Do you by any chance have the opportunity to try another power amplifier?
 
Process of elimination. Start at the source, CDP, Turntable, Streamer etc and start disconnecting. This should reveal which component is causing the issue.
 

3rdignis

Well-known Member
If it's dc, then a dc blocker before the extension blocks dc entering that extension.

But if a device on that extension creates dc, all other devises on that extension can be effected.

I have one big extension for my av equipment which helps with ground loops.

My dac and power amps are the only things attached to my dc blocker, then different extension.

My dac uses optical only, no ground loops.

My dac and power amp use xlr and my power amps have no ground other than xlr, my dac has ground.
 

3rdignis

Well-known Member
If hum/buzz is coming from you power amp transformer and through speakers with only power connected to amp that sounds like dc on mains. Put the dc blocker before power amp only with no signal cable connected. If this doesn't fix amp could be faulty.
 

3rdignis

Well-known Member
You should only hear amp transformer when you press your ear to the amp.

For digital you should hear no hum from your woofers.

For your kit you may hear hiss 2" - 6" from tweeters.
 

3rdignis

Well-known Member
How many speakers have you got connected to what?

Why use the 8000a?

For stereo I would connect your avr hdmi to tv, optical to dac, cd optical to dac to power amp.

Only connect devices that are susceptible to dc after the dc blocker, as few as possible. For stereo dac and power amp.

Keep all other kit on one other extension.
 

Helix Hifi

Well-known Member
Optical is preferred over coaxial. From my understanding he can only use two power strips.

But why not buy power strip which can accommodate more hifi components.

Can put link to dc blocker?
 

3rdignis

Well-known Member

3rdignis

Well-known Member

Mains power in, mains power out.

Stop dc in both directions.

Protect a unit from dc on mains.

If placed directly before a unit that creates dc will protect other units.

If before an extension will protect all units on that extension unless a devise on that extension Is creating dc on mains.

I would use one anyway, otherwise if at a later point you get dc you won't know until it rattles your transformer loose and degrades the audio signal.

I see no downside.
 
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