How to tame a really noisy AC circuit. Transformer? Line Selective UPS?

[Echolane]

I just bought a hand held device that would enable me to check the amount of electrical noise entering the AC circuit that provides power to my very good audio system. It measured over 4000 units!! Other rooms in the house, therefore other circuits, varied but were generally half that of the most important living room. To put this in perspective, I am told quiet a AC circuit should measure under 100. So I am on a mission to quiet this noise.

I have been offered a very expensive super audiophile transformer, but I’m hoping to find something less expensive. Tripp-Lite transformers were recommended and a four outlet option with hospital grade outlets can be had for around $500.

Meanwnile, a little more reading produced a suggestion for a line interactive UPS, which is one thpe of battery backup that works like this:

“A line interactive UPS is a battery-backup system whose battery is always engaged between the input AC and the output AC. This requires the electrical power to go through a conversion to DC (direct current) and then back to AC, which will remove all the noise.”

one problem with the UPS is I can’t seem to find one that matches the description in that it converts to DC and then back to clean AC. So I’m feeling quite confused.

I am not an electrician so I really don’t know how to evaluate the potential of these possibilities. Can anyone help me sort this out?

 

[Gregm]

I am on a mission to quiet this noise.

I have been offered a very expensive super audiophile transformer, but I’m hoping to find something less expensive. Tripp-Lite transformers were recommended and a four outlet option with hospital grade outlets can be had for around $500.

I'm not an electrician either, but have had the same problem & applied the solution recommended to you, with reasonably good results -- not a tripp-lite, but a custom-made 2.5kW, 1:1 transformer.
Subjectively, the sound was "cleaner", i.e. details were much more in evidence. I am not sure about dyamics but I don't think I suffered loss of dynamic swing.
Admittedly, the result was far better than the audiophile solutions I tried...

 

[Nelsen]

Ciao.
Sicuramente l'unica marca che produce apparecchi che risolvono il problema in modo radicale li produce Gigawatt.
ok non costano 500 $ ma sono gli unici che non fanno doppia conversione. Da ultimo ti raccomando attenzione sulla cevetteria di alimentazione che è estremamente importante come importante è il distributore di rete e la linea di massa.
Spero di esserti stato utile.

 

[ddk]

I just bought a hand held device that would enable me to check the amount of electrical noise entering the AC circuit that provides power to my very good audio system. It measured over 4000 units!! Other rooms in the house, therefore other circuits, varied but were generally half that of the most important living room. To put this in perspective, I am told quiet a AC circuit should measure under 100. So I am on a mission to quiet this noise.

I have been offered a very expensive super audiophile transformer, but I’m hoping to find something less expensive. Tripp-Lite transformers were recommended and a four outlet option with hospital grade outlets can be had for around $500.

Meanwnile, a little more reading produced a suggestion for a line interactive UPS, which is one thpe of battery backup that works like this:

“A line interactive UPS is a battery-backup system whose battery is always engaged between the input AC and the output AC. This requires the electrical power to go through a conversion to DC (direct current) and then back to AC, which will remove all the noise.”

one problem with the UPS is I can’t seem to find one that matches the description in that it converts to DC and then back to clean AC. So I’m feeling quite confused.

I am not an electrician so I really don’t know how to evaluate the potential of these possibilities. Can anyone help me sort this out?

First, a lower number whatever that means in context of your device doesn’t mean better sound specially if the solution is sticking a transformer in the mix. 2nd, if the other rooms in the house are showing a lower reading it might be one or more of your audio components contributing to this higher value, then what?

david

 

[AMR / iFi audio]

We have a few ways to fight noise on the mains.
We can go passive:
- isolation transformer
- passive filtering
Or active:
-active filters
-regenerators

Passive solutions are simpler and they usually introduce some additional impedance with mains. That is why some people say passive filters slow down the sound.
Active options are more complex, but they provide lower impedance, so they should not restrict dynamics.

Personally, I go for either active or no filtering.

 

[Kingrex]

I don't think your approaching this correct. For one, you seem to be trying to throw devices at the reading without any understanding what the reading means, what your measuring and what is causing the assumed noise.

 

[Nelsen]

Abbiamo alcuni modi per combattere il rumore sulla rete.
Possiamo andare passivi:
- trasformatore di isolamento
- filtraggio passivo
Oppure attivo:
-filtri attivi
-rigeneratori

Le soluzioni passive sono più semplici e di solito introducono un'impedenza aggiuntiva con la rete. Ecco perché alcune persone dicono che i filtri passivi rallentano il suono.
Le opzioni attive sono più complesse, ma forniscono un'impedenza inferiore, quindi non dovrebbero limitare la dinamica.

Personalmente, scelgo il filtro attivo o assente.

io trasformatore di isolamento e quanto di più attivo esista ;-)

 

[Atmasphere]

“A line interactive UPS is a battery-backup system whose battery is always engaged between the input AC and the output AC. This requires the electrical power to go through a conversion to DC (direct current) and then back to AC, which will remove all the noise.”

one problem with the UPS is I can’t seem to find one that matches the description in that it converts to DC and then back to clean AC. So I’m feeling quite confused.

All those devices do is make sure that the power keeps running for a while after the power goes out. In this way you have time to shut your computor off gracefully without losing any data. They do not need to produce clean power for that reason.

@Kingrex is right; without knowing the nature of the noise its a shot in the dark as to how to reduce it! Is there a particular reason why you are using this meter? IOW is there a problem in your system you are trying to address?

 

[christensenleif@msn.com]

what hand held device?
do you experience a problem or is the device telling you you have one?

 

[MarkusBarkus]

and what is causing the assumed noise.

@Echolane I echo what Kingrex and others have written. Is the circuit feeding your audio system a dedicated circuit? Or are other things also being fed from that circuit?

If it's only for the audio, is it a "home-run" meaning, direct from panel to audio outlet(s) without other breaks?

"Tracing" this out is the only way to proceed, IMO. Starting from the panel and thinking your way along. You might also want to consider your wire gauge and checking grounds and connections along the way. What the heck "units" are you measuring, BTW?

 

[microstrip]

I just bought a hand held device that would enable me to check the amount of electrical noise entering the AC circuit that provides power to my very good audio system. It measured over 4000 units!! Other rooms in the house, therefore other circuits, varied but were generally half that of the most important living room. To put this in perspective, I am told quiet a AC circuit should measure under 100. So I am on a mission to quiet this noise. (...)

What type of device were you using? What are these units? Unless you know about the spectra of noise these measurements tell very little and can be misleading to find a solution. Considering the price of many power devices IMHO we should have a proper analysis carried before going in such expenses - or simply listen to find what you prefer, probably much more reliable than many hand held devices.

 

[Echolane]

I'm not an electrician either, but have had the same problem & applied the solution recommended to you, with reasonably good results -- not a tripp-lite, but a custom-made 2.5kW, 1:1 transformer.
Subjectively, the sound was "cleaner", i.e. details were much more in evidence. I am not sure about dyamics but I don't think I suffered loss of dynamic swing.
Admittedly, the result was far better than the audiophile solutions I tried...

Were you able to measure the noise before and after you installed your custom made transformer?
it would be helpful to know more about your custom made transformer.
Lastly, we’re you able to measure the the before and after improvement with a meter?

 

[Echolane]

First, a lower number whatever that means in context of your device doesn’t mean better sound specially if the solution is sticking a transformer in the mix. 2nd, if the other rooms in the house are showing a lower reading it might be one or more of your audio components contributing to this higher value, then what?

I was very surprised to find lower numbers in other rooms! And I have no plausible explanation.
The measuring device I bought is a Trfield Line EMI Monitor..

I hope you can educate me with what you mean when you say lower numbers don’t mean better sound quality and your comment that sticking a transformer in the mix might not solve the problem. I repeat my statement that I am not an electrician and I will add that I am not an engineer either, so I really do not understand these issues in detail.

I have no idea which, if any, of my audio components might be emitting electrical noise. I have nine components in my stereo cabinet, most of them plugged into a Brick Wall surge protector and line conditioner. Other than the typical audio components, I have a pair of Quad ESL-63 electrostatic speakers plugged in as well as a number of lamps which use LED light bulbs. I have been told LED light bulbs are noisy but most of the time they are not lit., or only two are lit.

 

[Alrainbow]

I was very surprised to find lower numbers in other rooms! And I have no plausible explanation.
The measuring device I bought is a Trfield Line EMI Monitor..

I hope you can educate me with what you mean when you say lower numbers don’t mean better sound quality and your comment that sticking a transformer in the mix might not solve the problem. I repeat my statement that I am not an electrician and I will add that I am not an engineer either, so I really do not understand these issues in detail.

I have no idea which, if any, of my audio components might be emitting electrical noise. I have nine components in my stereo cabinet, most of them plugged into a Brick Wall surge protector and line conditioner. Other than the typical audio components, I have a pair of Quad ESL-63 electrostatic speakers plugged in as well as a number of lamps which use LED light bulbs. I have been told LED light bulbs are noisy but most of the time they are not lit., or only two are lit.

If you can post a link to the product. No one here is trying to make you feel it’s a waist. But many have used all kinds of products to measure various types of noise.
what They claim is a minefield to understand
some filters do lower noise in both directions meaning out to audio devices and back towards the power source.

 

[microstrip]

According to the information I could find about your device

"The Line EMI Meter measures electromagnetic interference in a single-phase AC power line. It plugs into a wall outlet (mains socket) and requires no battery. It immediately displays total line noise in millivolts peak to peak (range 1999.9 mVp-p, resolution 0.1 mVp-p) in the frequency range 10 KHz – 10 MHz (the frequency limits at which sensitivity is ½ of the maximum sensitivity). A speaker plays the sound of the EMI, amplitude demodulated, in order to identify the EMI source (such as an AM or shortwave radio station vs. a motor vs. an electric arc)."

this is simply a peak to peak broadband RF meter - useless to compare different mains points located at different zones that can have different types of noise. As it does not discriminate the frequency of the guilty interference, all it allows you is to try minimizing interference by try and guess. What type of sound do you hear on the speaker?

 

[Kingrex]

If you have a budget for transformer/filter can you use it to get a dedicated circuit to your rack.

 

[microstrip]

Probably you have done it, but did you try disconnecting the Ethernet router and the net cables?

 

[oldhvymec]

I'm new here so bare with me, I'll just ask.

Can you hear this noise you're measuring with the gadget you're using?

I've never had a noise problem I couldn't fix. Usually routing cables, using certain cables that need to be shielded, cable weaves, isolate equipment with "noise" issues (laptops and cable routers) from stereo equipment and checking for voltage difference between stereo equipment, usually fixes the issues.

I know I can turn the volume all the way up on any digital playback units I use and there is a blacker than black back ground. With Analog MM, MI, MC or RtR it's still very quiet.

I use modified Tripp Lite with added heavy copper IEC and silicone dampening. They maintain 120 on the button. I use 3 circuits. One 15 amp and 2 20 amp circuits. They are all dedicated and ALL on L2 of a 120/220-240 single phase service. I use L2 because all the light circuits in the house are on L1 so is the hair dryer, microwave and a few other things..

I roll a lot of different vintage tube systems. I'm very careful of 110 VAC systems and noisy transformers. A Variac has been a long time mechanical noise fixer for 45 years in that room.

If I can't hear it, I don't worry about it. I have pretty good ears and a bull horn to the ear usually removes any doubt.

BTW My speakers are 93% sensitive with 12 ohm subs and 94% with 12 ohm bass and mid columns. Small planars and ribbons, they hide nothing and reveal everything.

It is time to feed my chickens

Regards

 

[ddk]

I was very surprised to find lower numbers in other rooms! And I have no plausible explanation.
The measuring device I bought is a Trfield Line EMI Monitor..

I hope you can educate me with what you mean when you say lower numbers don’t mean better sound quality and your comment that sticking a transformer in the mix might not solve the problem. I repeat my statement that I am not an electrician and I will add that I am not an engineer either, so I really do not understand these issues in detail.

My point was that you’re equating a random number on a gadget to a problem that might not exist. You don’t know what your device is measuring or if 4000 unit of whatever even affecting your sound yet rushing to conclusions. You don’t have to be an engineer or an electrician to look at this rationally.

david

 

[microstrip]

My point was that you’re equating a random number on a gadget to a problem that might not exist. You don’t know what your device is measuring or if 4000 unit of whatever even affecting your sound yet rushing to conclusions. You don’t have to be an engineer or an electrician to look at this rationally.

david

I said the same in a technical way. And fortunately there is little rationality in many important things we do and write in this hobby.