Bodgit

Dedicated HiFi circuit design

Recommended Posts

7 hours ago, Bodgit said:

I'm going to be rewiring my house from top to bottom, its a 3 bed semi with extension to come so will of course have a dedicated mains circuit for the hifi. Am thinking of using 4mm T&E radial on a 32A MCB to 6 double unswitched sockets (MK Logic brand). Anyone got any suggestions for other ideas? There's only so many ways to wire a circuit, and using 4mm just allows extra cross sectional area (rather than 2.5mm).

A 4mm² T&E radial should be fine but be aware that how the cable is installed can reduce its current carrying capacity.

Personally I’d use switched sockets (the MK ones are usually cheaper than unswitched!) as it’s easier to completely isolate items.

Share this post


Link to post
Share on other sites
Posted (edited)

This is an idea not a recommendation. If I was going to do something like this, I would have an isolation transformer, and then a mains regenerator and fuse box to which the stereo would be connected. This would be referenced to a separate earth rod.

Edited by dave

Share this post


Link to post
Share on other sites

That's an awful lot of space to find and work involved Dave...........

Share this post


Link to post
Share on other sites
Moderator
8 hours ago, rabski said:

To revert to the point, which is install cable rather than equipment cable, the RA site states its installation cable needs to be double insulated to comply with regs and this can be done. However, at a price that is not stated. Neither is the method of double insulation.

My issue with the RA install cable is not the price, but that the blub states 'woven'. It is not clear what this means, but I assume it is a sort of plaited design. The idea behind this is that weaving mains cables has some benefits, but to my eyes, it could also have undesirable effects, such as increasing inductance. There are many good reasons why twisted/woven cables are a bad idea if higher currents are involved and there are many reasons why 'standard' mains cables for installation purposes are accordingly of an inline construction.

My issue with the RA cable is that it appears to be live and neutral only, no earth wire. Definitely non standard if it is used for mains installation.

Share this post


Link to post
Share on other sites
14 minutes ago, dave said:

This is an idea not a recommendation. If I was going to do something like this, I would have an isolation transformer, and then a mains regenerator and fuse box to which the stereo would be connected. This would be referenced to a separate earth rod.

Unfortunately, things like this throw up a whole load of potential safety issues and noncompliance to electrical regulations.

  • Upvote 2

Share this post


Link to post
Share on other sites
6 minutes ago, Tony_J said:

My issue with the RA cable is that it appears to be live and neutral only, no earth wire. Definitely non standard if it is used for mains installation.

There is an earth conductor, it does mention it in the specifications and if you look closely you can see it in the centre of the weave.

Share this post


Link to post
Share on other sites
Moderator
Posted (edited)
11 minutes ago, Blackmetalboon said:

There is an earth conductor, it does mention it in the specifications and if you look closely you can see it in the centre of the weave.

You're right - didn't spot that. 

Edited by Tony_J

Share this post


Link to post
Share on other sites
Moderator
31 minutes ago, dave said:

This is an idea not a recommendation. If I was going to do something like this, I would have an isolation transformer, and then a mains regenerator and fuse box to which the stereo would be connected. This would be referenced to a separate earth rod.

As BMB has observed, this kind of solution has its own issues wrt regulations.

I guess you could also contemplate a completely "off-grid" solution - a bunch of PV panels or a wind turbine on the roof, feed the output into a bunch of batteries for storage, then use the stored energy to drive your own private mains supply via inverters/regenerators etc., or even better, re-wire your hifi components for DC supply. The main issue I have with all of this is "Why Bother" when the standard mains supply fed to a competently designed PSU works just fine.

  • Upvote 2

Share this post


Link to post
Share on other sites
Moderator
32 minutes ago, dave said:

This is an idea not a recommendation. If I was going to do something like this, I would have an isolation transformer, and then a mains regenerator and fuse box to which the stereo would be connected. This would be referenced to a separate earth rod.

I realise this is speculation and an 'I would if' sort of idea, but for the sake of clarity, it ought to be pointed out that any electrical installation must have a connection to the mains earth at the supply. Adding a grounding rod can cause other issues, but regardless of that, it is certainly not acceptable, ever, as a substitute for 'proper' earthing.

Given a 'no holds barred' situation, I'd do none of the above. I'd keep the mains earth for all the chassis connections, completely isolate all the signal paths, and power everything with rechargeable batteries. Getting all the LT supplies that way would be simple, the 250V for all the small signal tubes wouldn't be a major problem, but 1kV or so for the 845s might be a bit harder. We can only dream.

Share this post


Link to post
Share on other sites

I think the full RA solution is compromised in terms of Regs and safety, using any kind of non standard cable will be frowned upon by a spark who will be signing it all off. Again, any kind of different earthing arrangements will be frowned upon and may introduce more problems than it solves.

it just makes sense to me, if rewiring the whole house, to put in a separate circuit for the hifi. Ring or radial, 2.5, 4 or 6mm cable, probably won't make that much difference.

Share this post


Link to post
Share on other sites
Moderator
3 minutes ago, Bodgit said:

it just makes sense to me, if rewiring the whole house, to put in a separate circuit for the hifi. Ring or radial, 2.5, 4 or 6mm cable, probably won't make that much difference.

It makes no sense to me to do that, given that all of your circuits, ring and radial, are connected together at a common point anyway, at your consumer unit. I.e., it will make naff all difference. The choice of when to use dedicated radial circuits Vs rings is about where the fuses/circuit breakers are placed, and what they protect, and not about noise/interference. It can't be about the latter, because the connection back at the CU doesn't insert any form of passive or active filtering in the path of the supply.

  • Upvote 2

Share this post


Link to post
Share on other sites
On 31/05/2019 at 10:05, Bodgit said:

I think the full RA solution is compromised in terms of Regs and safety, using any kind of non standard cable will be frowned upon by a spark who will be signing it all off. Again, any kind of different earthing arrangements will be frowned upon and may introduce more problems than it solves.

it just makes sense to me, if rewiring the whole house, to put in a separate circuit for the hifi. Ring or radial, 2.5, 4 or 6mm cable, probably won't make that much difference.

Russ is a snake oil salesmen, best ignored. Mains stuff does not affect performance.

Share this post


Link to post
Share on other sites
7 minutes ago, Muckplaster said:

Russ is a snake oil salesmen, best ignored. Mains stuff does not affect performance.

hi

does increasing a mains impedance affect performance ?

russ states that lowering the mains impedance is beneficial.

Share this post


Link to post
Share on other sites
Just now, Turk 182 said:

hi

does increasing a mains impedance affect performance ?

russ states that lowering the mains impedance is beneficial.

Yes, increasing mains performance can affect performance, usually of the device protecting the circuit. I’ve taken measurements at sockets as high as 18Ω, what was plugged in to them (luckily not a heavy load) still worked fine.

Share this post


Link to post
Share on other sites
2 minutes ago, Blackmetalboon said:

Yes, increasing mains performance can affect performance, usually of the device protecting the circuit. I’ve taken measurements at sockets as high as 18Ω, what was plugged in to them (luckily not a heavy load) still worked fine.

hi

thanks for the reply - i would like trevc, sorry, muckplasters opinion though as he claimed mains stuff does not affect performance !

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.