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Should my power conditioner hum?

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Re: Should my power conditioner hum?

Postby Martin Walker » Mon Mar 27, 2017 2:35 pm

mashedmitten wrote:DC riders are one part of it, but a mangled sine wave is another.

Right on mashedmitten!

I've certainly noticed this transformer hum as a result of a distorted mains waveform (I even went to the trouble of wiring up an old 9-volt AC wall wart and a couple of resistors as a potential divider so I could plug the mains waveform into my audio interface and examine it more closely when ever it happened (don't try this at home folks unless you're REALLY sure what you're doing ;) )

Odd harmonic distortion in the waveform (flattening of the waveform 'tips', typically resulting in around 1% measured THD in the mains 'sinewave') didn't result in any transformer buzzes.

NO TRANSFORMER BUZZ - 1% ODD HARMONIC DISTORTED MAINS WAVEFORM

MWmains-13-10-04-2pm-226volt-NOBUZZ.jpg


However, there was a loud transformer buzzer in my power amp as a result of even-harmonic distortion (even though the THD didn't rise any further), with visible discontinuities in the waveform around the zero crossings.

LOUD TRANSFORMER BUZZ - 1% ODD & EVEN HARMONIC DISTORTED MAINS WAVEFORM

MWmains-13-09-30-2pm-228volt-loudbuzz.jpg


Having said that, these buzzes came and went as the waveform changed - 95% of the time I don't hear these buzzes, even during brownouts (I once measured one down to 179v)


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Re: Should my power conditioner hum?

Postby Animesh » Mon Mar 27, 2017 2:41 pm

mashedmitten wrote:All I can think of is Keeping Up Appearances where Hyacinth Bucket rings the electric provider demanding she get clean, never been used electric delivered to her home lest it brush against her wall paper or fail to de-shoe before entering the residence.

Hahaha! Classic! :-)

Martin Walker wrote:I've certainly noticed this transformer hum as a result of a distorted mains waveform (I even went to the trouble of wiring up an old 9-volt AC wall wart and a couple of resistors as a potential divider so I could plug the mains waveform into my audio interface and examine it more closely (don't try this at home folks unless you're REALLY sure what you're doing )

Are you guys thinking that this could be causing my transformer hum? To be honest, I can just about wire a plug, and change a light bulb...so performing anything more complex than this would most probably be an accident waiting to happen! Is it worth calling in an electrician or a priest before going to the trouble of jettisoning my Furman?
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Re: Should my power conditioner hum?

Postby Martin Walker » Mon Mar 27, 2017 2:55 pm

Animesh wrote:Are you guys thinking that this could be causing my transformer hum?

No, as I mentioned above, these buzzes only happen to me when there's bad interference on the incoming mains waveform, probably due to someone nearby running some renegade high-powered electric appliance :headbang:

These buzzes only tend to happen in my neck of the woods (rural village surrounded by farmland) for a few seconds at a time, and then disappear again. Yours is a continuous buzz most probably due to an under-specified mains transformer (or more exactly, one correctly specified for a 60Hz mains supply that was never tested on a 50Hz one)


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Re: Should my power conditioner hum?

Postby Guest271017 » Mon Mar 27, 2017 3:06 pm

Martin Walker wrote:
Animesh wrote:Are you guys thinking that this could be causing my transformer hum?

No, as I mentioned above, these buzzes only happen to me when there's bad interference on the incoming mains waveform, probably due to someone nearby running some renegade high-powered electric appliance :headbang:

These buzzes only tend to happen in my neck of the woods (rural village surrounded by farmland) for a few seconds at a time, and then disappear again. Yours is a continuous buzz most probably due to an under-specified mains transformer (or more exactly, one correctly specified for a 60Hz mains supply that was never tested on a 50Hz one)


Martin

My understanding is the culprit could be blocks away or a neighbor. Could be a factory down the road operating 24/7 causing the mess.

Given your skill set, I'd simply take it to a friend's or relative that lived the next town over or such and see what it does there. If it hums, return the unit. If not, call the electrics man, oops, sorry....person. ;)
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Re: Should my power conditioner hum?

Postby Animesh » Mon Mar 27, 2017 3:15 pm

Martin Walker wrote:No, as I mentioned above, these buzzes only happen to me when there's bad interference on the incoming mains waveform, probably due to someone nearby running some renegade high-powered electric appliance

Aha, all makes sense now - apologies, I clearly didn't quite follow your post there!

mashedmitten wrote:Given your skill set, I'd simply take it to a friend's or relative that lived the next town over or such and see what it does there. If it hums, return the unit. If not, call the electrics man, oops, sorry....person.

My skill set? Well I never ;-) !! Haha very fair point...mashedmitten!

So now all I need is a friend in a nearby town... *cue tumble weed rolls*

On a serious note, thanks very much for the suggestion! I'll try to do this posthaste!
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Re: Should my power conditioner hum?

Postby Guest271017 » Mon Mar 27, 2017 3:18 pm

Animesh wrote:
Martin Walker wrote:No, as I mentioned above, these buzzes only happen to me when there's bad interference on the incoming mains waveform, probably due to someone nearby running some renegade high-powered electric appliance

Aha, all makes sense now - apologies, I clearly didn't quite follow your post there!

mashedmitten wrote:Given your skill set, I'd simply take it to a friend's or relative that lived the next town over or such and see what it does there. If it hums, return the unit. If not, call the electrics man, oops, sorry....person.

My skill set? Well I never ;-) !! Haha very fair point...mashedmitten!

So now all I need is a friend in a nearby town... *cue tumble weed rolls*

On a serious note, thanks very much for the suggestion! I'll try to do this posthaste!

Was debating adding a :mrgreen: to that bit to clear confusion of meaning, but you seemed a sport so I risked it. :lol:
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Re: Should my power conditioner hum?

Postby Forum Admin » Mon Mar 27, 2017 3:34 pm

I have a Samson unit (bought from Germany) and it hums loudly too. I gave up using it and bought one of these Trojan SPS06 power sequencers from Studio Spares:
https://www.studiospares.com/Cables-Leads/Mains-Distribution/Trojan-SPS06-15A-Power-Sequencer_348010.htm

It doesn't do 'conditioning' but is a great one-switch turn-on that delays the start-up and switch-off of each socket to avoid massive spiking. I have distribution boards plugged into each 13A rear socket. Works well for me.
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Re: Should my power conditioner hum?

Postby Animesh » Mon Mar 27, 2017 3:58 pm

mashedmitten wrote:Was debating adding a :mrgreen: to that bit to clear confusion of meaning, but you seemed a sport so I risked it. :lol:

Well played sir!! :clap: :lol:

Forum Admin wrote:I have a Samson unit (bought from Germany) and it hums loudly too. I gave up using it and bought one of these Trojan SPS06 power sequencers from Studio Spares:
https://www.studiospares.com/Cables-Lea ... 348010.htm

Thanks very much for this link, it looks great! I will have a trawl through for ones with IEC outlets! I'm quite taken with the Bryant ones Hugh mentioned as there is also the sequential startup/shutdown option, but definitely keen to explore! Thanks again for sharing your thoughts.
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Re: Should my power conditioner hum?

Postby Guest271017 » Mon Mar 27, 2017 6:01 pm

Animesh wrote:
mashedmitten wrote:All I can think of is Keeping Up Appearances where Hyacinth Bucket rings the electric provider demanding she get clean, never been used electric delivered to her home lest it brush against her wall paper or fail to de-shoe before entering the residence.

Hahaha! Classic! :-)

Taking it further, you could be Richard when he got volunteered into fixing the church's electrics.

Stop what you're doing and step away from the fuse box. :lol:
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Re: Should my power conditioner hum?

Postby Animesh » Mon Mar 27, 2017 6:11 pm

mashedmitten wrote:Stop what you're doing and step away from the fuse box.

Now just you hang on for a minute...the other day, I managed to replace the batteries in my mouse - unaided!!

With this kind of progress I'll soon be writing for SOS!
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Re: Should my power conditioner hum?

Postby Guest271017 » Mon Mar 27, 2017 6:16 pm

Animesh wrote:
mashedmitten wrote:Stop what you're doing and step away from the fuse box.

Now just you hang on for a minute...the other day, I managed to replace the batteries in my mouse - unaided!!

With this kind of progress I'll soon be writing for SOS!

You're over-qualified as is. :bouncy:

I'll get me coat. :oops:
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Re: Should my power conditioner hum?

Postby Guest271017 » Mon Mar 27, 2017 6:18 pm

Animesh wrote:
mashedmitten wrote:Stop what you're doing and step away from the fuse box.

Now just you hang on for a minute...the other day, I managed to replace the batteries in my mouse - band-aided!!

:o Hope the wound wasn't deep. :bouncy:
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Re: Should my power conditioner hum?

Postby Animesh » Mon Mar 27, 2017 6:32 pm

:lol:
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Re: Should my power conditioner hum?

Postby BigZ427 » Sun Jul 12, 2020 6:47 pm

I solved this issue. It’s a design flaw with the PL Plus. The transformer that runs the rack lights is what is buzzing.

I unplugged the leads to it and it’s dead silent and the everything works perfectly, just the rack lights don’t work.

I emailed furman and have not heard back.

It seems like the power comes in, is stepped up to supply all the 9 outlets and then is reduced to power the lights. The reduction causes the hum/buzz. I read a lot of forums and everyone that owns the cheaper models of Furman’s say that their units are dead silent. What is the common denominator in those units? No rack lights.
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Re: Should my power conditioner hum?

Postby Arpangel » Mon Jul 13, 2020 7:09 am

James Perrett wrote:As others have said, humming US made gear is very common - and it isn't just the cheap stuff. My Eventide H3000 is one of the worst offenders. Mind you, I have a couple of UK made items that hum audibly too.

Yes, I sold my H3000 because of this hum, I tried everything, but you just can’t cure it. Totally unacceptable.
I’d get a European conditioner, but as others have said, is it really necessary?
As for the one button solution, is that a good idea? Having everything come on at the same time would worry me, there is a preferred switch on sequence, to avoid mains spikes.
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