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Occasional hum

Printed From: Graham Slee Hifi System Components
Category: And the rest
Forum Name: Audio System Set-Up
Forum Description: Discussions about getting the best from your system (Digital section now moved)
URL: https://www.hifisystemcomponents.com/forum/forum_posts.asp?TID=5596
Printed Date: 24 Feb 2024 at 1:45pm
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com


Topic: Occasional hum
Posted By: CageyH
Subject: Occasional hum
Date Posted: 07 Mar 2023 at 6:36am
Occasionally, when listening to my system (through speakers or headphones) I get a short burst of a humming noise.
How do I find out what the source of this noise is, and more importantly, how do I get rid of it?

I will be checking to see if it is source dependent later today, as I noticed it yesterday when listening to vinyl.

At a guess, I would say it is probably in the 50Hz range, but it could be a multiple of 50Hz. It usually lasts for about 2 or 3 seconds.

I am thinking of fitting a filtered IEC to my mains block as a first step, as I think it is noise on the mains. Any other suggestions?

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Kevin
European loan coordinator, based near Toulouse, France.



Replies:
Posted By: Graham Slee
Date Posted: 07 Mar 2023 at 7:49am
There are two types of mains frequency noise: 1. 50Hz hum; 2. 100Hz buzz. In addition there is interference noise from TV and monitor screens which may have LCD (or similar) excitation frequencies, sometimes 75Hz.

There can be contact noise where a connection is on its last legs, thus removing the shielding function intermittently, resulting in "mains hum".

As you only recently noticed it ("as I noticed it yesterday when listening to vinyl"), then is there anything that has changed recently, or any new household electronics or electricals?

A mains filter cannot remove mains frequency noise because the noise is the mains frequency, and removing it removes the mains.

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That none should be able to buy or sell without a smartphone and the knowledge in how to use apps


Posted By: RichW
Date Posted: 07 Mar 2023 at 8:14am
Plug-in lamp dimmers on the same ring as hifi can induce noise.

Plug-in Adjustable Dimmer Switch for Home Lamps | eBay


Posted By: CageyH
Date Posted: 07 Mar 2023 at 8:19am
Thanks for the reply Graham.
It is not new, but yesterday on headphone listening it was there.
I had heard it before using my speakers, but was surprised to hear it yesterday.

I think I would go for option 2. 100Hz buzz.
Nothing has changed recently, but I know I have noisy mains, as we have a smart meter, power line network adapters, air conditioning and a heat pump.

So if there is nothing I can do to filter it out, I guess I will have to live with it.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 07 Mar 2023 at 8:23am
Originally posted by RichW RichW wrote:

Plug-in lamp dimmers on the same ring as hifi can induce noise.

Plug-in Adjustable Dimmer Switch for Home Lamps | eBay

Thanks. I don’t have ring circuits. My HiFi is on a dedicated line, but it all feeds back to the same place….


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Graham Slee
Date Posted: 07 Mar 2023 at 9:10am
Not a case of living with it. More like an ongoing investigation.

I and others can only give examples. Here's another.

I had an Hadcock GH 228 unipivot arm and upgraded to a GH 242.

Rather than being quiet, the new arm would introduce mains hum/buzz every now and then.

This was because the arm tube metal wasn't making electrical contact with the arm base, because the unipivot wasn't pressing "hard enough" together to always cause an electrical contact. Otherwise, the unipivot was doing its job as a bearing.

As such, the arm tube surrounding the arm wires wasn't an effective sheild, and then it was, and then it wasn't.

Eventually I said sod it and bought a fuss-free Technics.

We can only give you our stories in the hope something clicks (or doesn't...Wink).


-------------
That none should be able to buy or sell without a smartphone and the knowledge in how to use apps


Posted By: RichW
Date Posted: 07 Mar 2023 at 10:48am
DC on the mains, or asymmetrical AC mains is reported to make transformers buzz.
I used to hear this intermittently but now rarely for an unknown reason..
A DC blocker might be worth a trial.


Posted By: Graham Slee
Date Posted: 07 Mar 2023 at 11:10am
Originally posted by RichW RichW wrote:

DC on the mains, or asymmetrical AC mains is reported to make transformers buzz.
I used to hear this intermittently but now rarely for an unknown reason..
A DC blocker might be worth a trial.

Hi Richard, I think he's got one of those in his power amp.


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That none should be able to buy or sell without a smartphone and the knowledge in how to use apps


Posted By: CageyH
Date Posted: 07 Mar 2023 at 1:04pm
Originally posted by RichW RichW wrote:

DC on the mains, or asymmetrical AC mains is reported to make transformers buzz.
I used to hear this intermittently but now rarely for an unknown reason..
A DC blocker might be worth a trial.

Thanks Rich, unfortunately it is not transformer buzz. I built and fitted a DC blocker into my amplifier.
The buzz can be heard through the speakers/headphones and only lasts 1 or 2 seconds, so could be a fridge or something else turning on/off.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: BackinBlack
Date Posted: 07 Mar 2023 at 4:41pm
I can't imagine you haven't considered mobile phone interference. I have occasionally noticed intrusions from my phone a it keeps "in touch" with the network. Most often when the local mast is not available due to reaching max capacity or maintenance and the phone has to increase signal strength.
Just a thought.

Ian


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Just listen, if it sounds good to you, enjoy it.


Posted By: gwebster
Date Posted: 07 Mar 2023 at 5:05pm
Originally posted by CageyH CageyH wrote:

The buzz can be heard through the speakers/headphones and only lasts 1 or 2 seconds, so could be a fridge or something else turning on/off.
Possibilities:
  • fridge
  • freezer
  • air-con
  • heat pump


-------------
Inspire Apollo tt, O/L modded RB250, Ortofon 2M Black, Slee Different Approach inspired Phono, Putzeys Pre, Cusat, Raspberry Pi/Volumio, Bitzie, Self Load Invariant Power, Acoustic Energy AE509s


Posted By: CageyH
Date Posted: 07 Mar 2023 at 5:19pm
Originally posted by gwebster gwebster wrote:

Originally posted by CageyH CageyH wrote:

The buzz can be heard through the speakers/headphones and only lasts 1 or 2 seconds, so could be a fridge or something else turning on/off.
Possibilities:
  • fridge
  • freezer
  • air-con
  • heat pump

You are correct, but I don't want to turn any of those off!
Having a fridge/freezer, a fridge and a freezer in the house makes this a challenge.
Soon I can see if it is the heat pump, as I will be able to turn the heating off soon - hopefully!


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: patientot
Date Posted: 08 Mar 2023 at 5:21pm
No advice but I wish you luck in sorting this out. Problems like this can be very annoying.


-------------
SL-1200 MK7 (modified) + Reflex M + PSU-1 used with AT150-40ML, AT VM95ML, Stanton 680mkII + Ogura, and Shure M35X cartridges.


Posted By: CageyH
Date Posted: 08 Mar 2023 at 5:22pm
New discovery tonight - It is only on the analogue side of my system, so not likely to be a mains issue?
Makes me wonder if it is RFI or EMI now.

The digital side uses USB/coax into an Audio GD DI2014, which feeds the DAC via another coax cable. Connections between the DAC, Preamp and amplifier are all balanced.

On the analogue side, I use coax interconnects cables from SL1200 into the BB3, core for signal and shield as return, and a “balanced” RCA cable with the screen connected at the source end only, going from BB3 to Pre.

I think my money is on the last cable being the “problem child.”

The expertly made cables in this house have just left for a loan, so I will have to try one of my “CageySat” cables between the Phonostage and preamp.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 08 Mar 2023 at 5:23pm
Originally posted by patientot patientot wrote:

No advice but I wish you luck in sorting this out. Problems like this can be very annoying.

Thanks. Luckily I can’t hear it when the music is playing, but I know it is there.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 08 Mar 2023 at 5:32pm
For clarity, the phonostage is not one of Graham’s designs. It is a valve (MM)/hybrid design(MC uses JFETs to amplify the signal, AFAIK). It was a another “lockdown” project I built to keep me sane. It is equipped with a Schaffner medical grade filter in the IEC socket.

I am in the lucky position of having several well designed phonostages “available” to swap in to see if it is the phonostage.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Fatmangolf
Date Posted: 08 Mar 2023 at 7:05pm
I am hoping CageySat helps.

-------------
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: CageyH
Date Posted: 08 Mar 2023 at 7:10pm
It didn’t, so I need to move further up the chain.

-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 08 Mar 2023 at 7:12pm
I may try a pair of Lautus. The ferrites may be just the job.

-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Fatmangolf
Date Posted: 08 Mar 2023 at 7:13pm
Fingers crossed for you Kevin.

-------------
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: lfc jon
Date Posted: 08 Mar 2023 at 8:53pm
Same here.

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Reflex M, Solo (both with PSU-1) CuSat50, Lautus, Spatia & Spatia links cables. Ortofon Bronze.


Posted By: CageyH
Date Posted: 08 Mar 2023 at 9:04pm
I think I have fixed it….

It is either a ferrite I have put on a power cable, or the network cable I moved to put the ferrite on the cable.

I have not heard the buzz for about 10 minutes, which is unusual….

Fingers crossed.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Fatmangolf
Date Posted: 08 Mar 2023 at 9:26pm
Are you able to listen to music again?

-------------
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: CageyH
Date Posted: 08 Mar 2023 at 9:52pm
I was always able to listen to music, it is just the low level hum annoyed me in the quiet bits.

It is fixed though, so I am happy. I was wearing my headphones as I fitted the ferrites on various cables. No difference was audible until I clipped one around the cable that feeds my power block. The pitch of the buzz increased slightly, and then went silent. It has not been back since, and I have moved the network cable back to where it was.

I can’t explain why it is fixed….


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Graham Slee
Date Posted: 09 Mar 2023 at 8:16am
Well done, Kevin!

Neither can I explain exactly why it is fixed.

But I do know that RF (frequencies that are in the radio spectrum that aren't always due to TV or radio transmission), will trigger oscillations at the strongest local frequency (this being the ever present mains), in components operating close to "the edge".

That "edge" is constantly changing due to a thing called "progress", so can happen to any sensitive analogue circuit. Progress disregards the playing of records. In other words, record playing equipment is rather inconvenient for progress, and "they" never thought vinyl would make a comeback as it did. So it has become a no man's land regarding "the standards", because "they" know they are also unable to work it out. Therefore, it can always be blamed on the equipment manufacturer, or the user - anybody but "they".

There'd have been exactly the same problems with live performance, had it not been for forward thinking, and a thing called the hearing loop, which made the dynamic mic a thing of the past. They too, as well as mixer input stages, pick up all the airborne crapito. So now they're condenser which is non-magnetic. Additionally, they contain a preamp right there at the source.

Another thing about the microphone is that it is fully shielded - even where the sound passes through is a Faraday cage.

With record players however, outputs of a millivolt or so from a magnetic cartridge (with its seriously non-linear output increasing at +6dB per octave) ARE NOT SHIELDED. The industry refuses to adapt with the progress, although it can easily do so, but has its head firmly planted where the sun don't shine. It is at record players that the standards writers give up the ghost. A kind of "let the children play" attitude, hoping that its generations will pass away one day and take their record players with them.

So, some acceptable modern interference happens somewhere, which can be just about anywhere, and that triggers a sequence of events resulting in spurious oscillations. And then it's "find the needle in the haystack" time.

A ferrite on a cable makes a "half turn transformer" such that the frequency the ferrite becomes lossy at, is short circuited to itself, and does what all ouslem birds do. The frequency will be well into RF, and not mains frequency, but remember, it's the trigger.


-------------
That none should be able to buy or sell without a smartphone and the knowledge in how to use apps


Posted By: CageyH
Date Posted: 09 Mar 2023 at 8:51am
Thanks for the detailed insight into this Graham. My approach was based on "It may help" and it was a question of working through the cables until I found the right one. 

If it was not the cable, I was going to put a properly built phono stage in the system to eliminate the "DIY" model I have, but fortunately, I did not have to do that yet.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 10 Mar 2023 at 1:22pm
An interesting development regarding this subject.
My "Smart Meter" let the magic smoke escape last night/this morning.

So I am patiently waiting for a replacement meter. It could be related to the noise I have heard recently.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Graham Slee
Date Posted: 10 Mar 2023 at 1:38pm
I was going to mention chattering contacts but couldn't think of any apart from a dodgy central heating thermostat. But, yes, a smart meter has a contactor (or more), which is a large relay, and all relays that chatter eventually burn out.

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That none should be able to buy or sell without a smartphone and the knowledge in how to use apps


Posted By: CageyH
Date Posted: 10 Mar 2023 at 1:43pm
The meter should be changed today. It is not that old.
I will remove the ferrites from the power cable when the new one is fitted, and see if there is any hum/buzz with the new meter.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 10 Mar 2023 at 2:31pm
Apparently caused by ants in the meter.
The "owner" of the meter tells me I need to put some product in the meter box to stop the ants. 

I reminded him that neither the meter, or the box belong to me, nor are they on my property, and as I don't have a key, how can I, even if I wanted to?

The conversation was cut short as they found a problem with the installation.....


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Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 10 Mar 2023 at 4:44pm
And I think they have now found the root cause. A dodgy connector on the telegraph pole….

-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 10 Mar 2023 at 5:57pm
Meter replaced, connector (and possibly old cable) replaced.
Result? No hum/buzz audible on the vinyl side of my system.

I would never have found that fault, so I am happy it has been replaced


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Fatmangolf
Date Posted: 10 Mar 2023 at 8:23pm
Thanks Kevin, that is good news on several levels.

-------------
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: Chris Firth
Date Posted: 10 Mar 2023 at 9:24pm
I'd be surprised if they've replaced any cable - most grid issues can be laid at the feet of insufficient torque at the supply tails into meter.



Posted By: CageyH
Date Posted: 12 Mar 2023 at 9:56am
After a period of silence, the hum came back last night, but at a lower level.
I dug out my old mains regenerator and have plugged everything but the power amp into it.
The result is that silence has now returned, and hopefully the hum/buzz is banished from my system.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: gwebster
Date Posted: 12 Mar 2023 at 10:31am
Have you still got the ferrites in use on your cables?

-------------
Inspire Apollo tt, O/L modded RB250, Ortofon 2M Black, Slee Different Approach inspired Phono, Putzeys Pre, Cusat, Raspberry Pi/Volumio, Bitzie, Self Load Invariant Power, Acoustic Energy AE509s


Posted By: CageyH
Date Posted: 12 Mar 2023 at 10:36am
Yes, I put them back on before I fitted the regenerator.

-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 15 Mar 2023 at 9:36am
Still confused by this.
As soon as my phono stage is turned on in my system, the buzz of the AG1500 stops, but there is a very faint noise audible through my headphones/speakers.

I plugged in my Amazon Commercial “Pure Sine Wave” 1500VA UPS (which is usually used for my NAS) and the unit does not buzz. Neither do I have the occasional hum/buzz through the headphones/speakers. Is a cheap UPS (SMPS based?) really the solution?

I do not want to spend thousands on a HiFi mains conditioner.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Fatmangolf
Date Posted: 15 Mar 2023 at 6:38pm
It is experimental at this stage. How does the music sound with the UPS?

-------------
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: CageyH
Date Posted: 15 Mar 2023 at 7:27pm
Flat. Cry

I would rather have the occasional buzz.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Fatmangolf
Date Posted: 15 Mar 2023 at 7:42pm
I'd do the same fwiw.

-------------
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: Graham Slee
Date Posted: 15 Mar 2023 at 8:24pm
Originally posted by CageyH CageyH wrote:

I do not want to spend thousands on a HiFi mains conditioner.

So what would one of those achieve?



-------------
That none should be able to buy or sell without a smartphone and the knowledge in how to use apps


Posted By: CageyH
Date Posted: 15 Mar 2023 at 8:42pm
Possibly the same as a “double conversion” inverter, but with a grossly inflated price tag.

-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 16 Mar 2023 at 7:40pm
The filtered IEC inlets arrived today. So I took my extension block apart only to find that I could not fit the IEC inlet, as there is a metal shield running down the middle of the enclosure.

So I put it back together, making sure all of the screws for the cables were tight. I then plugged everything back in, but in a different order (against the manufacturers recommendations). I also reorientated the mains block in an attempt to dress my cables.

I have yet to hear the buzz tonight. I don’t want to tempt fate just yet…


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Fatmangolf
Date Posted: 16 Mar 2023 at 8:23pm
I hope it stays that way. 🤞

-------------
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: CageyH
Date Posted: 17 Mar 2023 at 10:52pm
I tempted fate....



-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 18 Mar 2023 at 7:57am
Would an isolation transformer be a suitable device to cut down the noise?

-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 19 Mar 2023 at 1:07pm
I have a temporary fix, as what ever is causing the noise is not something I can turn off.
So my system is plugged in to the mains, with the exception of the phono stage.
The system is now silent, but I want to get rid of the AG1500 power regenerator, as I know this is throwing noise back into the mains.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 21 Mar 2023 at 12:08pm
Can a ground loop be intermittent?
Every time I think I have fixed the issue after a few hours of silence, it comes back.

It does sound a bit like a ground loop hum, that lasts for maybe one to two seconds.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 24 Mar 2023 at 5:36pm
Further steps taken.

I tried an iFi iPurifier. It did nothing, so got sent back.
I have some more ferrites on my phono leads between TT and phono stage. The occasional buzz has reduced in intensity, but it is still there.

Only one cable left in the analogue chain to treat now. The earth cable between TT and phono stage.
I guess it is just like an aerial, just sitting there to pick up RFI. It is quite thin, so I may have to wrap it around a ferrite.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: lfc jon
Date Posted: 24 Mar 2023 at 7:32pm
I must be so lucky, I remember having noise problems with my system but a simple purchase of a Tacima mains conditioner sorted it all out. That's going back quit a few years ago now.

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Reflex M, Solo (both with PSU-1) CuSat50, Lautus, Spatia & Spatia links cables. Ortofon Bronze.


Posted By: CageyH
Date Posted: 25 Mar 2023 at 10:23am
In my case, the Tacima mains block would not have helped. I was chasing a mains related problem, as my “mains regenerator” stopped the noise, but I think it was/is EMI/RFI based.

I fitted a ferrite bead to my TT earth wire last night, (it was a spare one from my mains cable beads, so is massive)  and there is a very slight trace of a buzz now.
I think I need an RFI/EMI resistant earth lead, and I can finally point this subject to bed.

It has been an interesting journey so far, which is almost finished, I hope. Now I just need to work out how to make this lead.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Chris Firth
Date Posted: 25 Mar 2023 at 10:40am
Originally posted by CageyH CageyH wrote:

I think I need an RFI/EMI resistant earth lead, and I can finally point this subject to bed
So a shielded ground cable, eh?

Where are you going to ground the shield to..........?


Posted By: CageyH
Date Posted: 25 Mar 2023 at 10:42am
Exactly…
But how do I stop it from being an aerial?
I think there is a mobile phone mast about 1km away. This could be the source.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Chris Firth
Date Posted: 25 Mar 2023 at 10:48am
Radio Hams might run something outside and into the ground.


Posted By: CageyH
Date Posted: 25 Mar 2023 at 10:51am
So if I grounded the shield to the mains earth, with a fly lead, would it work?

I am going to try a couple of ferrites (of the correct size) first, and then look at other options.
I may try removing the lead altogether, but so far, ferrites seem to be the answer.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Chris Firth
Date Posted: 25 Mar 2023 at 10:54am
Is there anything with a mains ground connected in your audio system?
Hook it up to there.

You posted before I finished typing.

Something else crossed my mind.
Are you still using AK's modified arm, and what is the arm tube made of?



Posted By: CageyH
Date Posted: 25 Mar 2023 at 12:53pm
The phono stage is connected to the mains, as is the pre and the power.

Yes, I have AKs modified arm, with an aluminium arm tube. 

I have just made a new grounding lead, with a floating shield. It has been plugged in for 15 minutes, and no signs of a hum. It may not be the theoretically optimal solution, but if it works, who cares?


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Chris Firth
Date Posted: 25 Mar 2023 at 12:59pm
Thumbs Up


Posted By: CageyH
Date Posted: 26 Mar 2023 at 9:29am
The even simpler solution has been found. Just disconnect the grounding cable from the phono stage.
Why did I not think of this earlier?

Why, because it still hums…. Cry

Digital is so much easier.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 29 Mar 2023 at 8:31pm
I think it is power related.

Out of desperation, I fitted ferrite beads on the internal power cables inside my phono stage, and the noise has dropped dramatically. I am hard pushed to hear it at normal listening levels (without music playing) so I have bought an Isotek power filter to see if that will help.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: gwebster
Date Posted: 30 Mar 2023 at 9:47am
Originally posted by CageyH CageyH wrote:

I think it is power related.

Out of desperation, I fitted ferrite beads on the internal power cables inside my phono stage, and the noise has dropped dramatically. I am hard pushed to hear it at normal listening levels (without music playing) so I have bought an Isotek power filter to see if that will help.
Is it worth swapping out your "lockdown special" valve hybrid phono stage and reinstating your previous solid state phono? 
As a valve unit, there is inherently more mains related guff floating about (heater, higher dc supply) in it.


-------------
Inspire Apollo tt, O/L modded RB250, Ortofon 2M Black, Slee Different Approach inspired Phono, Putzeys Pre, Cusat, Raspberry Pi/Volumio, Bitzie, Self Load Invariant Power, Acoustic Energy AE509s


Posted By: CageyH
Date Posted: 30 Mar 2023 at 10:09am
No can do.
I don’t own a SS phono stage. I do have plenty available, but they are not mine. Wink

I am determined to fix the issue. I am a bit stubborn about these things. Hopefully it will be fixed at the weekend.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Fatmangolf
Date Posted: 30 Mar 2023 at 6:41pm
Fingers crossed.

-------------
Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: CageyH
Date Posted: 31 Mar 2023 at 4:24pm
Today I have received my Isotek Evo Gemini mains filter. It is a bit of an expensive 2 way mains block, costing me just over €200.

I have plugged in it to my system, feeding my phono stage and preamp. So far, so good. The system has been powered up for over an hour, and no sign of the Buzz.

If this is what it takes to get rid of the noise (and hopefully have a better signal due to the lack of the noise) then it will be money well spent. I am sure I could probably build something cheaper, but this was much easier.


-------------
Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Ernie
Date Posted: 31 Mar 2023 at 9:32pm
Be interesting to hear what you think of the conditioner. Keep us posted. Hopefully it cures your itch.

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There are 10 kinds of people. Those who understand binary and those who don't.


Posted By: CageyH
Date Posted: 01 Apr 2023 at 8:03pm
It does not affect the system in anyway bad that I can hear, so I am happy with it.
The system almost seems to send more details, due to the lack of noise.

It has a very bright blue LED built in it though.


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Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 12 Dec 2023 at 12:47pm
The hum is still there, and it is annoying me.
If you listen (amongst the hiss) to this clip, you can possibly hear it. -  https://drive.google.com/file/d/11W048At3m5d7KcalhMxty-9un6VDKxOY/view?usp=share_link - https://drive.google.com/file/d/11W048At3m5d7KcalhMxty-9un6VDKxOY/view?usp=share_link

This is a condensed 3 minute clip, so you can see that the hum is not constant, but it almost sounds like a harmonic of 50Hz to my untrained ears.

I have a temporary fix, using my mains regenerator gets rid of it completely, but I would still like to know what is causing this, so I can fix the issue.


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Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 16 Dec 2023 at 10:20am
Playing around with Audacity, I have managed to produce a plot, that confirms it is mains related:
https://drive.google.com/file/d/1BussEKjYFLIOfFVnNHTQ5qxh0FekSQo1/view?usp=sharing - https://drive.google.com/file/d/1BussEKjYFLIOfFVnNHTQ5qxh0FekSQo1/view?usp=sharing

There is a noise at 50Hz and a bigger one at 100Hz.
I guess I don't have many option of filtering this 100Hz noise out?

It makes me wonder if this is ground loop related, and if so would a mains isolation transformer help?



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Kevin
European loan coordinator, based near Toulouse, France.


Posted By: CageyH
Date Posted: 16 Dec 2023 at 1:22pm
I have altered the earthing scheme and cable layout, and have managed to reduce the hum significantly.
It seems that it was either an earth loop, or loop pick up.
It is not perfect, but I will do a better job in the Christmas holidays.


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Kevin
European loan coordinator, based near Toulouse, France.


Posted By: BackinBlack
Date Posted: 16 Dec 2023 at 1:37pm
Glad to know that you're getting somewhere near solving the problem. Earth loops/pickup can be so difficult to isolate. I find that turntables are the worst culprit, earthing arrangements can be so haphazard, or even non existant.

Happy Listening
Ian


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Just listen, if it sounds good to you, enjoy it.


Posted By: CageyH
Date Posted: 16 Dec 2023 at 2:23pm
It has been about an hour since I made my changes. 
I have not had the faintest sign of the hum.

I think I can put this subject to bed, and move on. Thumbs Up


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Kevin
European loan coordinator, based near Toulouse, France.


Posted By: Fatmangolf
Date Posted: 16 Dec 2023 at 3:55pm
Well done and thank you for sharing.

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Jon

Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: RichW
Date Posted: 19 Dec 2023 at 8:13am
Well done for sorting out the problem Kevin.




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Majestic/Enigma, Accession MM & MC.


Posted By: patientot
Date Posted: 20 Dec 2023 at 4:29pm
Glad it worked out.


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SL-1200 MK7 (modified) + Reflex M + PSU-1 used with AT150-40ML, AT VM95ML, Stanton 680mkII + Ogura, and Shure M35X cartridges.



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