BMU noise

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Ed345
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BMU noise

Unread post by Ed345 »

My BMU has been in place for about a month, and has consistently been making a fairly loud buzzing. At decent listening volumes it is a lower level than the hum through the speakers that it has eliminated, but it is quite obstructive at lower volume levels and when not playing music.

I have been planning to find a wooden box that I could put it in and dampen the inside, but then today the hum stopped. It has been completely silent all day.

Is there any way that it could have bed in or changed in some way, or has some big nasty been removed from the local mains supply?

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Dr Bunsen Honeydew
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Re: BMU noise

Unread post by Dr Bunsen Honeydew »

No it is the quality of your mains changing, get one of these if it bothers you.

https://www.atlhifi.com/shop/fully-asse ... d-in-case/

Ed345
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Re: BMU noise

Unread post by Ed345 »

Interesting. I’ll wait and see how it behaves for a while. If it stays quiet then I won’t need anything. If it gets noisy again, then maybe I’ll get that filter.

Do you think it would have an effect on the music, or does the BMU render that null and void?

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Dr Bunsen Honeydew
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Re: BMU noise

Unread post by Dr Bunsen Honeydew »

Arguable. I have convinced myself it interferes a little, but a very little that could just be my mood. BUT bad transformer buzzing is a lot worse.

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CN211276
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Re: BMU noise

Unread post by CN211276 »

Dr Bunsen Honeydew wrote: Tue Jan 15, 2019 6:59 pm No it is the quality of your mains changing, get one of these if it bothers you.

https://www.atlhifi.com/shop/fully-asse ... d-in-case/
I bought one of these following the Doc's recommendation and it has been silent ever since. Previously it used to hum at times, especially first thing in the morning.
Main System
NVA BMU, P90SA/A80s (latest spec), Cube 1s, TIS, TISC(LS7)
Sonore OpticalRendu, Chord Mscaler & Qutest, Sbooster PSs
Network Acoustics Eno, ifi iPurifier3, AQ JB FMJ, Cisco 2940 & 2960
DH Labs ethernet, BNC & USB cables, Farnells cat 8 ethernet cable

Second System
NVA P20/ A20, Cubettes, LS3, SSP, SC
Sonore MicroRendu, Chord Mojo 2 MCRU PSs, AQ Carbon USB cable & JB FMJ

Headphones
Grado SR325e/Chord Mojo, Beyerdynamic Avetho/AQ DF Colbat

RIP Doc

Stemcor1990
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Re: BMU noise

Unread post by Stemcor1990 »

I also purchased one and it has reduced the “noise on my mains”. I would certainly recommend the blocker. Delivery from Bulgaria was about a week.

keepitsimplestupid
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Re: BMU noise

Unread post by keepitsimplestupid »

and if you have more DC than that simple two cap unit can deal with try one of these, he does bare pcbs as well

https://sjostromaudio.net/cart/en/mains ... -unit.html

Ed345
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Re: BMU noise

Unread post by Ed345 »

After 3 days of silence the loud buzz has come back and it seems like it’s here to stay. Think I’ll be trying that filter after all.

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Dr Bunsen Honeydew
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Re: BMU noise

Unread post by Dr Bunsen Honeydew »

The supply companies should get it made illegal to pollute your mains electricity, as it is illegal to pollute your mains water. This is the equiv of intermittent brown stained water coming out the tap.

A neighbour of yours is screwing your pleasure.

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Re: BMU noise

Unread post by Ed345 »

Dr Bunsen Honeydew wrote: Sat Jan 19, 2019 9:47 pm A neighbour of yours is screwing your pleasure.
Rather embarrassingly, it turns out I’ve been screwing myself. I tracked down the problem to a humidifier that I hade constantly running on low setting. Great big hum on low setting, lesser hum on high setting. Inky black silence 😉 when it’s turned off.

Time to start living with dry air...

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