DC on the line

[ralflar]

The transformers in my D-200s hum, so I knew I have a DC component riding on my AC power. It did not bother me too much since it is not audible unless I'm close.

That changed last night when I put my ears close to the woofers of my Vantages, and heard a low level hum. I am fairly certain that hum was not there when I set up the Vantages last December. Since then neither the components nor the cabling in my system have changed. Anyway, this does bother me.

The hum occurs on both speakers whether the speaker cables are connected or not. I tried it with the Vantages plugged into the high current outlets of my Belkin PF60 power console, into the stronger filtered other outlets of the console, as well as straight into the wall. No change.

So I think I can conclude that the problem is not due to a ground loop, and that the power console is ineffective as a low frequency filter. OK, so that is no surprise.

Any ideas as to what could be the cause other than DC?

 

[twich54]

Two things.... first off all transformers hum...at least to a small degree.

secondly....to the best of my knowledge all Vantage speakers have a low freq rumble 'at idle', I have confirmed this with Jim Powers, as a matter of fact , I was the one who brought it to his attention, over a yaer ago. His reaction......."don't worry" !!! they all do it, after testing those coming off production !!!

 

[ralflar]

It sounds a bit like what you hear when you hold a Nautilus shell to your ear, like a distant rumble. There is also a chirping noise of higher frequency which reminds me of very distant cicada at night. The low frequency hum can be heard from at least 1 foot away.

Does this describe what you are hearing from your Vantages?

 

[twich54]

that's it, I have yet to NOT hear it from any that I have come across in the past year. We had a discussion about a year ago on the forum and all were in agreement then tht they all do it. Beyond a foot or so it is completely inaudible.

has anyone gotten a reasonable explanation ???

 

[Charliemike]

that's it, I have yet to NOT hear it from any that I have come across in the past year. We had a discussion about a year ago on the forum and all were in agreement then tht they all do it. Beyond a foot or so it is completely inaudible.

has anyone gotten a reasonable explanation ???

I gotta say I'm pretty disappointed that our PF60s don't seem to be doing all that much.

 

[ralflar]

Thank you Dave. In a way it is a relief to know that nothing seems to be wrong.

It still bothers me, though. The woofer membrane is clearly oscillating in order to produce that noise. It means it always shakes, never idles. The woofer amp will always use power to move the woofer membrane, even when idling.

This 24/7 activity simply does not sound like a good recipe for longevity, both electrically and mechanically speaking...

Folks, do Summits behave like this, too???

 

[ralflar]

I gotta say I'm pretty disappointed that our PF60s don't seem to be doing all that much.

Aww, come on! They still look pretty and have the highest surge protection spec around the block: over 7000 Joules.

 

[Charliemike]

Aww, come on! They still look pretty and have the highest surge protection spec around the block: over 7000 Joules.

As far as surge protection goes, I'm completely confident. I just wish there was a bit more line conditioning.

 

[benleeys]

Thank you Dave. In a way it is a relief to know that nothing seems to be wrong.

It still bothers me, though. The woofer membrane is clearly oscillating in order to produce that noise. It means it always shakes, never idles. The woofer amp will always use power to move the woofer membrane, even when idling.

This 24/7 activity simply does not sound like a good recipe for longevity, both electrically and mechanically speaking...

Folks, do Summits behave like this, too???

Yea, ralflar. My Summits do hum, but you have to put your ear real close to detect it.

 

[twich54]

Thank you Dave. In a way it is a relief to know that nothing seems to be wrong.

It still bothers me, though. The woofer membrane is clearly oscillating in order to produce that noise. It means it always shakes, never idles. The woofer amp will always use power to move the woofer membrane, even when idling.

This 24/7 activity simply does not sound like a good recipe for longevity, both electrically and mechanically speaking...

Folks, do Summits behave like this, too???

I agree 100%, here's a thought......when we have the M/L guys all gathered together for dinner on Sunday nite at "The Gathering" this June in Lawrence we will hold them captive untill they come up with a solution ! Now come on everybody, get registered so we can show some strentgh !!!

 

[ralflar]

As far as surge protection goes, I'm completely confident. I just wish there was a bit more line conditioning.

From what I can tell from Internet research, most if not all passive "line conditioning" means filtering of the AC at frequencies beyond the audio spectrum, say 100kHz. As far as I am concerned any such passive line conditioning is a placebo.

 

[ralflar]

Yea, ralflar. My Summits do hum, but you have to put your ear real close to detect it.

Lucky you, I can hear mine from more than 2 feet away if all the other noise sources in my apartment (AC, fridge) idle. In a way I hoped that the answer had been "nope, my Summits don't hum at all". It would have been a reason to upgrade .

 

[risabet]

PS Power nee PS Audio

made a device called the Humbuster which took care of the DC on the line that causes T-former hum. They are no longer being made but you can find them on A-gon and E-Bay from time to time.

 

[ralflar]

Great that you mention this, I have been looking into the PS Audio UPC-200HB, "HB" as in humbuster.

Do you have first hand experience with the original Humbuster? The UPC sells for $500, DC removal and (unquantified) surge protection included. It has 2 "humbusted" and 2 regular outlets.

Alternatively, CIAudio will release the XDC-2 lowcut filter very soon. 2 filtered outs good for 7.5 A each for $300.

I don't know which way to go.

 

[ralflar]

I agree 100%, here's a thought......when we have the M/L guys all gathered together for dinner on Sunday nite at "The Gathering" this June in Lawrence we will hold them captive untill they come up with a solution ! Now come on everybody, get registered so we can show some strentgh !!!

Nice moves Dave . I want to attend, I really do. To date I still don't know if I can. I may have family over right then. Their idea of good sound is five or more speakers distributed around the four sides of a room, and fed by something which can generate "surround sound"... Their favorite brand is B&Ose.

 

[risabet]

Great that you mention this, I have been looking into the PS Audio UPC-200HB, "HB" as in humbuster.

Do you have first hand experience with the original Humbuster? The UPC sells for $500, DC removal and (unquantified) surge protection included. It has 2 "humbusted" and 2 regular outlets.

Alternatively, CIAudio will release the XDC-2 lowcut filter very soon. 2 filtered outs good for 7.5 A each for $300.

I don't know which way to go.

No, all I know about them is that they did what PS said they did, transformers stopped humming.

 

[benleeys]

Lucky you, I can hear mine from more than 2 feet away if all the other noise sources in my apartment (AC, fridge) idle. In a way I hoped that the answer had been "nope, my Summits don't hum at all". It would have been a reason to upgrade .

ralflar,

Hum heard from 2 ft away is LOUD. Actually the 'hum' in my Summits is more like low end white noise - a kind of shhhh sound. It disappears the moment I switch off the power. I think it exists in all Summits, because I heard it at my dealer's place too. But then, it could actually be a hum like yours, only I got wax in my ears!

 

[ralflar]

Ben, don't worry about your ears, let me clarify.

When the AC blows, any attempt at critical or relaxed listening is pointless. I have not even tried if I can hear the speakers hum when the AC is on. The normal background hum from the fridge is tolerable but even that has to be off to hear the speaker buzz from 2.5' away. With it on the hum can be heard approx. 1' away.

Better now?

 

[risabet]

Are there any other $10,000, now $12,000, SS components in which hum/noise is acceptable? Regardless as to whether it can be heard 2 ft away or not, SS amplifiers should be functionally silent w/o a signal. YMMV

 

[ralflar]

I agree. While transformer hum may be somewhat normal, the amps in Vantages/Summits should be silent.

Do Summits go for 12k now? I thought the price increase was 10%.