AC/DC questions plus BMU ones

[Ithilstone]

Since the visit of electrician couple of weeks ago my mind was occupied with question of mains quality and how it relates to audio gear safety and music quality. I searched this and other forums and that's what I come up with (please correct me if I am wrong)

There are 2 main type of problems with electric in standard houses
DC pollution (internal coming from household items and external coming from other houses or industrial plants near by etc) and voltage issues.
On paper everyone should get 230V at 50Hz but it is rarely a case - In my house it is anything from 244V to 252V according to electrician.

Both of those have rather small impact on safety or live span of audio gear - except extreme cases, as transformers in power supplies should deal with most of it.

But unfortunately both have a degradation impact on music quality.

What I am struggling with is:
1 What is our worst enemy DC pollution or excessive voltage or bad mix of both?
2 Which one makes transformers to buzz?
3 Is BMU dealing with both problems? If not what else can be used combined with BMU
4 Can a PC be connected to BMU alongside audio gear (again according to electrician all of it PC amps dacs etc uses at most 600W measured but normally around 350W-400W)

[Dr Bunsen Honeydew]

Take the mains bollocks on other forums with a pinch of salt. Only with some valve amps especially Chinese ones will high voltage be a problem. DC and AC distorted waveform from many reasons are the problem.

1 DC and AC pollution
2 DC
3 BMU gives out the same voltage as goes in, high or low, all it does is convert 0 - 240v to 120 - 120v. DC is blocked, AC distortion is passed but is sorted by proper power supplies.
4 there is no point as a BMU will make no difference to it, and it may back emf digital distortion onto the secondary side of the BMU. BMU is for hi-fi systems.

[Ithilstone]

Take the mains bollocks on other forums with a pinch of salt.

That's exactly why I ask those question here as i know i will get simple and honest answer

3 BMU gives out the same voltage as goes in, high or low, all it does is convert 0 - 240v to 120 - 120v. DC is blocked, AC distortion is passed but is sorted by proper power supplies.
4 there is no point as a BMU will make no difference to it, and it may back emf digital distortion onto the secondary side of the BMU. BMU is for hi-fi systems.

3 As for sorting out AC pollution and distortion something like that would be needed:
http://www.powerinspired.com/store/ag15 ... -1742.html
if it works as advertise...
4 So ideal would be: PC, modems, printers, scanners and NAS to AC regenerator
and all audio gear to BMU??
Now what would be better to plug BMU directly to main socket as we are not worried about AC distortion as we know you are building proper power supplies or it still be better to connect BMU to AC regenerator type of gear and put less stress in power supplies ??

If I get it all right it would work like:
AC regenerator would clean AC of distortion/pollution and give stable 230V then BMU would convert 0 - 240v to 120 - 120v. and clean it of DC pollution ( as that AC regenerator does not advertise anything about blocking/filtering DC I assume it would still be there)

[Dr Bunsen Honeydew]

3 no
4 FFS I said the opposite.

Sorry you are talking bollocks. Anything computer or to do with your computer system plug direct into the mains via a surge protector (which should NEVER be used with hi-fi). Plug the hi-fi into a BMU. I would not waste my money on a cheap regenerator, it seems only the really expensive ones work but for £thousands.

You are assuming a lot of things wrongly.

AC distortion is changed by the BMU as it acts as a cancelling circuit (same signal opposite polarity cancels) everything else is dealt with by a proper power supply as in the NVA you own - problem solved so no problem.

[Ithilstone]

So forget about AC regulator - cannot afford expensive one...
buy a surge protector (any recommendation???)
save up for BMU

You are assuming a lot of things wrongly. - not a first time
and that's why I ask questions - even if stupid ones - still saves me money

[Dr Bunsen Honeydew]

They are cheap as hell built into four way mains blocks.

[Classicrock]

For computers just get a cheap mains strip with built in surge protector. If you want something better, say you have your own servers for a web site or business, then I suggest look into uninterruptible power supplys (UPS). Vary from cheap to £1000's.

[Ithilstone]

NAS it was I am worried about - 10TB with 5TB of backup: all my photos etc.
I dont remember having a black out in last 8 years so UPS is not essential
but my lights and monitor started to flicker every now and then so
something not right with my mains.

would that be OK:
https://www.comms-express.com/products/ ... s-230v-uk/

[Dr Bunsen Honeydew]

Anti surge is dead simple circuit consisting of a couple of varistors - https://en.wikipedia.org/wiki/Varistor

How you tart it up in what it is put into depends on how stupid you are and how much money you want to throw away.

[kimangelis]

I don't completely understand why you would want to plug a PC or a NAS into a BMU. So far as I understand a BMU provides a cleaner AC current to various hi-fi items (I have 2 x Power amp, CD and DAC connected to mine). A BMU is not a surge protector nor a protection against power outages.

All you need over and above a surge protection block is a small UPS. These units will protect your PC/NAS against AC spikes plus provide a battery backup should mains power fail. You can also configure a UPS to cleanly power down a PC or NAS so avoiding nasties.

Any computer system that contains the likes of PC/Server, disc units NAS or otherwise, should have a UPS connected in-line.