A Balanced Mains Unit
I have to admit something.
I am a complete sceptic when it comes to most accessories. Audiophile fuses, expensive mains cables, a grands worth of interconnects, incredibly expensive equipment racks, you name it, I don't necessarily believe in it.
Each to their own though, If you believe whatever accessory makes a difference, and you believe that you can hear a difference, then to you, there is a difference. And if it helps you have better sound, then great. Just don't expect me to believe it too.
When it comes to cables, I believe I can hear subtle differences, but I'm not about to spend a huge amount of money on them. I can understand to an extent why they have an influence on the sound based on their electrical properties, but all the marketing bullshit is mostly just that. Bullshit. To get you to part with in some cases obscene amounts of money. Oh please, 1500 quid for 2 bits of wire? are you having a giraffe?......... The law of diminishing returns really does come into effect in my view. But again, if you think the change is worth what you have paid, then who am I to tell you how to spend your money.
This kind of brings me to the next point.
Mains regeneration, mains treatment etcetera etcetera. I have a view that if the psu in your amp, deck, pre, whatever is doing its job, that mains electricity shouldn't be an issue, but logically it should make a difference to things like the motor in a lenco, as this has no psu, it is directly powered from the mains...
We all know that what does come out of the wall is not necessarily what should be coming out of the wall, mains voltage is not always nominally 230v at 50hz. Mine when measured is between 248 and 252 most of the time. The 50hz sine wave that alot of ac motors in turntables use to set their speed is generally about as stable as a hippo on ice skates, with alot of the wave peaks clipped off, and a less than perfect waveform when looked at on a scope. And all sorts of switching noises, spikes, high frequency interference, rf pickup, you name it, its there
A mains regenerator will take the crap coming in from the wall, rectify it to dc, convert it back into ac and generate a proper 50hz waveform on the ac supply. This requires alot of high power handling components and can be very very expensive. But it does give you a 'perfect' supply.
In my view, which it should be said is a little naive, a power amp, preamp etcetera that has on board rectification, pi filters, rfi filters and the like in order for it to work shouldn't be affected by a mucky supply. The designers know what comes out of the wall is not always what it says on the tin.
So I could never justify it to myself to spend thousands on a mains regenerator.
But there are other options.
Enter the balanced power supply.
Essentially what you have, is a massive toroidal isolation transformer, with a centre tapped secondary winding. Typically you will see these with a 115-0 115-0 primary and 115-0 115-0 secondary. When the secondary winding has the two '0' taps connected together you have a centre tap, which is connected to earth, and you get a summed 230v, where 115 comes out on one side of the winding and 115 out of the other. Because the centre tap is connected to earth, you get one side of the winding in phase, and the other side out of phase.. When one of the 115v outputs is connected to live, and one connected to neutral, your equipment that is plugged into it will get the full 230v, but what you get is a supply that has all the spurious noise on the mains supply removed by cancellation due to the inverted phases of each side of the secondary.
There will be a certain amount of regulation from the transformer too, the larger the transformer, the worse its frequency response will be, which in this case is a good thing. The worse the frequency response is, the less high frequency crap will get through from the primary to the secondary in the first place.
It wont stop mains fluctuations, and it wont give you a perfect 50hz ac, but it will give you a whole load of interference cancellation.
Intellectually this makes complete sense, and the concept is how balanced xlr cables work, having a hot and a cold side. I was still sceptical..........
This was until my dad procured a 1000va isolation toroid on a whim and built one. And I heard his system with it in place.
The most prominent difference was that the entire frequency range sounded cleaner, and the top end was clearer. Reasonably subtle initially, I would describe it as walking around all day with your glasses on you don't notice they are dirty, then you clean them on your shirt, and suddenly clarity of vision is restored.
He took it out, and we were back to dirty glasses.
I was now not so sceptical. So a plan was hatched, an identical toroid was procured, and one was built. His balanced power supply was breadboarded on a sheet of ply and was entirely open, not very safe for anyone to be around. Not really a problem in his house as it was out of the way and only he was going to use it. He built it, and is not a fool. so wasn't about to blow himself up on it.
This approach was a complete no no for me, I have kids. And animals. And a missus who might want to put some music on.
So it was built into a proper case, essentially double insulated as there are no metal fixings anywhere on the casework, the casework is all non conductive material (ply doesn't conduct obviously) and a captive lead.
I am a complete sceptic when it comes to most accessories. Audiophile fuses, expensive mains cables, a grands worth of interconnects, incredibly expensive equipment racks, you name it, I don't necessarily believe in it.
Each to their own though, If you believe whatever accessory makes a difference, and you believe that you can hear a difference, then to you, there is a difference. And if it helps you have better sound, then great. Just don't expect me to believe it too.
When it comes to cables, I believe I can hear subtle differences, but I'm not about to spend a huge amount of money on them. I can understand to an extent why they have an influence on the sound based on their electrical properties, but all the marketing bullshit is mostly just that. Bullshit. To get you to part with in some cases obscene amounts of money. Oh please, 1500 quid for 2 bits of wire? are you having a giraffe?......... The law of diminishing returns really does come into effect in my view. But again, if you think the change is worth what you have paid, then who am I to tell you how to spend your money.
This kind of brings me to the next point.
Mains regeneration, mains treatment etcetera etcetera. I have a view that if the psu in your amp, deck, pre, whatever is doing its job, that mains electricity shouldn't be an issue, but logically it should make a difference to things like the motor in a lenco, as this has no psu, it is directly powered from the mains...
We all know that what does come out of the wall is not necessarily what should be coming out of the wall, mains voltage is not always nominally 230v at 50hz. Mine when measured is between 248 and 252 most of the time. The 50hz sine wave that alot of ac motors in turntables use to set their speed is generally about as stable as a hippo on ice skates, with alot of the wave peaks clipped off, and a less than perfect waveform when looked at on a scope. And all sorts of switching noises, spikes, high frequency interference, rf pickup, you name it, its there
A mains regenerator will take the crap coming in from the wall, rectify it to dc, convert it back into ac and generate a proper 50hz waveform on the ac supply. This requires alot of high power handling components and can be very very expensive. But it does give you a 'perfect' supply.
In my view, which it should be said is a little naive, a power amp, preamp etcetera that has on board rectification, pi filters, rfi filters and the like in order for it to work shouldn't be affected by a mucky supply. The designers know what comes out of the wall is not always what it says on the tin.
So I could never justify it to myself to spend thousands on a mains regenerator.
But there are other options.
Enter the balanced power supply.
Essentially what you have, is a massive toroidal isolation transformer, with a centre tapped secondary winding. Typically you will see these with a 115-0 115-0 primary and 115-0 115-0 secondary. When the secondary winding has the two '0' taps connected together you have a centre tap, which is connected to earth, and you get a summed 230v, where 115 comes out on one side of the winding and 115 out of the other. Because the centre tap is connected to earth, you get one side of the winding in phase, and the other side out of phase.. When one of the 115v outputs is connected to live, and one connected to neutral, your equipment that is plugged into it will get the full 230v, but what you get is a supply that has all the spurious noise on the mains supply removed by cancellation due to the inverted phases of each side of the secondary.
There will be a certain amount of regulation from the transformer too, the larger the transformer, the worse its frequency response will be, which in this case is a good thing. The worse the frequency response is, the less high frequency crap will get through from the primary to the secondary in the first place.
It wont stop mains fluctuations, and it wont give you a perfect 50hz ac, but it will give you a whole load of interference cancellation.
Intellectually this makes complete sense, and the concept is how balanced xlr cables work, having a hot and a cold side. I was still sceptical..........
This was until my dad procured a 1000va isolation toroid on a whim and built one. And I heard his system with it in place.
The most prominent difference was that the entire frequency range sounded cleaner, and the top end was clearer. Reasonably subtle initially, I would describe it as walking around all day with your glasses on you don't notice they are dirty, then you clean them on your shirt, and suddenly clarity of vision is restored.
He took it out, and we were back to dirty glasses.
I was now not so sceptical. So a plan was hatched, an identical toroid was procured, and one was built. His balanced power supply was breadboarded on a sheet of ply and was entirely open, not very safe for anyone to be around. Not really a problem in his house as it was out of the way and only he was going to use it. He built it, and is not a fool. so wasn't about to blow himself up on it.
This approach was a complete no no for me, I have kids. And animals. And a missus who might want to put some music on.
So it was built into a proper case, essentially double insulated as there are no metal fixings anywhere on the casework, the casework is all non conductive material (ply doesn't conduct obviously) and a captive lead.
I wont post a circuit for it, There are plenty of them out there, and protection is a hotly debated topic on several forums and other places. I have done it how I see as safe, some others may do it differently.
as you can see here, I chose to use a double pole breaker on the transformer secondary for safety. This trips if there is a current imbalance between the live and neutral lines, so if for example a fuse blows in a piece of equipment and cuts off the live side, the breaker will sense that there is no current in that side of the circuit, but current flowing in the other side and trip to cut the power to both sides. There is also a thermistor on the primary so that current inrush as the transformer core charges is limited on switch on. This stops the socket rcd from tripping on the house consumer unit
as you can see here, I chose to use a double pole breaker on the transformer secondary for safety. This trips if there is a current imbalance between the live and neutral lines, so if for example a fuse blows in a piece of equipment and cuts off the live side, the breaker will sense that there is no current in that side of the circuit, but current flowing in the other side and trip to cut the power to both sides. There is also a thermistor on the primary so that current inrush as the transformer core charges is limited on switch on. This stops the socket rcd from tripping on the house consumer unit
The wiring is done using proper mains twin and earth cable so the current handling is the same as a wall socket
I would not advise that anyone builds one of these without researching it very thoroughly, and having the skills to do this kind of work. Remember, you are dealing with the mains supply here, and the mains supply will kill you if you don't know what you are doing. It might not look like much, but it still requires just as much preparation, knowledge and safety as any other piece of equipment.
What I would recommend though is to listen with one in place if you can. There are several companies who build these who would be happy to loan one with a full money back guarantee.
I think it has made a difference to my system for the better, and I wouldn't be without mine now. The outlay to build it was not very much at all, probably around 60 quid in parts, and maybe 10 hours to build it from scratch.
Bear in mind that a 1000va transformer is rather expensive, airlink for example can supply them, and I got this transformer fo a very very (veryveryvery) good price which was nowhere near the going rate for a new transformer of this type. So my build cost figures are rather skewed, and the casework was built from scraps I had hanging around, with veneer that was left over from another job so is not included in those costs.
Not so sceptical now............. On the issue of mains at least.............
I would not advise that anyone builds one of these without researching it very thoroughly, and having the skills to do this kind of work. Remember, you are dealing with the mains supply here, and the mains supply will kill you if you don't know what you are doing. It might not look like much, but it still requires just as much preparation, knowledge and safety as any other piece of equipment.
What I would recommend though is to listen with one in place if you can. There are several companies who build these who would be happy to loan one with a full money back guarantee.
I think it has made a difference to my system for the better, and I wouldn't be without mine now. The outlay to build it was not very much at all, probably around 60 quid in parts, and maybe 10 hours to build it from scratch.
Bear in mind that a 1000va transformer is rather expensive, airlink for example can supply them, and I got this transformer fo a very very (veryveryvery) good price which was nowhere near the going rate for a new transformer of this type. So my build cost figures are rather skewed, and the casework was built from scraps I had hanging around, with veneer that was left over from another job so is not included in those costs.
Not so sceptical now............. On the issue of mains at least.............