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Post by pinkie on Jan 2, 2016 9:15:15 GMT
How I would love to rig up a dummy look alike with 4 sockets wired direct, and send that out on a loan scheme. I am completely certain (based on similar exercises previously) that it would change the sound in a similar subtle, not night and day way. Sadly the only person well equipped to carry out such an experiment has no commercial interest in doing so.
But the other amusing aspect of these balanced power supplies generically, is that they measurably do not do the thing that is their primary claim. Namely remove noise on the input from the output. They can isolate grounds, filter dc , and change the noise fed to ground, but in a domestic setting these can be done without the compromise to safety these devices create.
If a balanced mains power supply removes noise from its input, a balanced interconnect would remove noise from its input too. Obviously it doesn't. It removes noise ADDED to the interconnect not any noise already on the signal BEFORE the interconnect. How would it know what is noise and what is signal?
It's not hard to show that algebraically. Just remember balanced is balanced whether you create it with a transformer or an amplifier, whether you are talking a mains signal or a 5mv one.
But dc filtering and changes to grounding can have effects.
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Post by John on Jan 2, 2016 9:30:37 GMT
I am going to put this in another thread as if you wish to talk about if balanced units work or not then lets discuss it somewhere else
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Post by John on Jan 2, 2016 9:35:34 GMT
I would like to add for me the difference is not subtle but not night and day either It is a improvement I think many people will appreciate
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Post by pinkie on Jan 2, 2016 9:42:59 GMT
I am going to put this in another thread as if you wish to talk about if balanced units work or not then lets discuss it somewhere else Thanks John. The comment was intended as generic - it was the loan scheme aspect and the opportunity to trial a ringer (or lack of it) that caused the thought on the other thread. And as I noted, there may be reasons - primarily associated with grouniding arrangements, why a Balanced Power Supply could make a difference to the sound. So maybe the thread title should be "how does Balanced Mains make a difference?"
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Post by MartinT on Jan 2, 2016 9:45:35 GMT
Richard, your comment is disingenuous. If you are really 'completely certain' that there is no effect then you stand to have egg on your face. This kind of polite calling us fools is disrespectful, but I guess it's all in the name of debate.
Do you really think we go around imagining performance improvements when there are none? How many times do we try something that doesn't work? If your measurements don't see a difference then you are measuring the wrong things. The differences that a BMU or regenerator make are obvious if your system is sufficiently resolving.
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Post by John on Jan 2, 2016 9:45:50 GMT
Yes I thought it best to keep this separate and a good general debate
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Post by John on Jan 2, 2016 9:48:08 GMT
I like to point out a lot of recording Studios use Balanced power
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Post by MartinT on Jan 2, 2016 10:39:29 GMT
the opportunity to trial a ringer Do you have any evidence or reason to believe that? If the BMU doing the rounds was a 'ringer', why wouldn't it be the model that was selling, if it was that effective? I ask genuinely because I've borrowed a LOT of kit over the years and I've never suspected one item of being a ringer. Indeed, one item was the reverse because it was wired incorrectly, and my dissatisfaction with it is recorded here in TAS.
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Post by pinkie on Jan 2, 2016 11:29:43 GMT
the opportunity to trial a ringer Do you have any evidence or reason to believe that? If the BMU doing the rounds was a 'ringer', why wouldn't it be the model that was selling, if it was that effective? I ask genuinely because I've borrowed a LOT of kit over the years and I've never suspected one item of being a ringer. Indeed, one item was the reverse because it was wired incorrectly, and my dissatisfaction with it is recorded here in TAS. Martin - I absolutely DO NOT think the BMU doing the rounds was a ringer. Nor do I think that a Balanced Power Supply, whether a BMU or any other, CANNOT change the sound of a HiFi. Allow me to separate 2 issues I muddled in that post (because they are linked in my mind) In the past at PT we did more than a few audition tests where nothing changed and the audience heard differences. There have been plenty of such tests carried out by others. It is therefore reasonable to assume that the effect would work as well with a balanced supply making a difference as it did previously in speaker cable tests. Note - both speaker cables and Balanced Mains CAN change the sound. But also, and this is what I was referring to, audiences positively assert they hear differences in speaker cables, which match their marketing expectations, even when behind the blanket the same cables are being plugged back in every time - and not the cables held up and shown to the audience. Its a well documented (personally witnessed) phenomena. Balanced Mains would not be immune to it. But I was assuredly NOT suggesting that an item I have never seen was a ringer. Only that, along the lines of the solid state amp with fake glowing tubes on the top - it would have been an interesting experiment to carry out - and one only the maker of the device could attempt - and pretty obviously (and fairly) wouldn't want to. The more serious point was about understanding what Balanced Mains does - which appears to be clouded in some mythology. Specifically the claim that balanced connections, whether mains or signal, can "clean" noise from their input. And therefore, in the context of the new thread John has created - "what is going on with Balanced Mains"? And the question - what is a balanced connection? And how could a balanced connection remove noise from an input? Specifically how does the balanced connection - not how is it implemented - remove noise? Not - what is the effect of a transformer? What does balanced mean? How can it remove noise from an input to the connection? Why does that only work for mains and not balanced signal connections? Is that less confusing?
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Post by pinkie on Jan 2, 2016 11:32:56 GMT
I like to point out a lot of recording Studios use Balanced power They do. But why? Tackling earth loops is probably the primary reason - at least originally.
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Post by MartinT on Jan 2, 2016 11:40:36 GMT
Better! I am not an expert at the exact mechanism behind a BMU sounding better than raw mains, but two I can think of for certain: 1) DC blocking 2) Not efficiently coupling high frequency hash through to the equipment These alone would be reason enough, but there may be other mechanisms at work, too.
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Post by John on Jan 2, 2016 12:16:05 GMT
My System has a dedicated earth (along with its own consumer unit and spur) installed by a electrician so whilst tackling earth loops is part of what a balanced mains unit is doing I am not sure if it is the whole answer. As for biased listening I actually got rid of my last BMU as it was no longer making a difference so suggesting this I find a bit offensive
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Post by terrybooth on Jan 2, 2016 12:20:47 GMT
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Post by pinkie on Jan 2, 2016 12:21:40 GMT
Martin
I can think of more reasons than that - particularly ground loop elimination in situations with equipment with chassis ground leaks.
The question was not "Does balanced mains do anything"? Or even "is it the best way to achieve it"?
The question was "what does balanced mean"? And how could a balanced connection remove noise from the input ? - as claimed by some
Regarding "positives" like DC blocking - a good question would be - "is there an equally convenient and safer way of doing it?" I have a simple DC blocker on my subwoofer which tackled transformer noise caused by dc offset (or arguably a mains transformer with insufficient margin - dropping the voltage with a variac had the same effect). But my DC blocking circuit costs a tenner at most and involves no safety compromises of the sort which balanced mains creates- particularly balanced mains without RCBO's on the output .
But to repeat a simple question
"what does balanced mean"? And how could a balanced connection remove noise from the input ?"
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Post by pinkie on Jan 2, 2016 12:31:27 GMT
that doesn't answer the question. I am not disputing that a balanced connection rejects noise imposed ON THE CONNECTION. I can prove that algebraically. The question was not about what it does with any noise which might otherwise be added between the 3 pin plug stuck into a balanced power supply, and the bit of equipment at the other end of it. The question was what can a balanced connection do about noise already on the supply coming into the Balanced power supply? We have 2 bits of wire. Wire A goes from the socket in the wall of your house to the Balanced Power supply. WIre B goes from the balanced power supply to the NAD 3020 amplifier sitting on my desk as I type. There is noise in the room. The noise is 10 units per meter of cable. Wire A and Wire B are both 1 metre Use Wire B straight into the mains in the wall - it gets 10 units of noise on it Use Wire B into the balanced power supply, and by virtue of the balanced connection it gets ZERO - yes ZERO units of noise added to it But Wire A is picking up 10 units of noise - just like Wire B did when it was plugged into the wall What does the balanced supply do with the 10 units of noise picked up by Wire A? Does it a) cancel it so there is now zero units of noise on Wire B? b) not change it -so the 10 units of noise coming into the Balanced supply are carried through to Wire B - which now has 10 units from wire A and ZERO of its own, because it is a balanced connection, making 10 units in total) (This is clearly a very simplified schematic!) How would a balanced connection on Wire B remove the noise from Wire A? The balanced connection - not filters, DC blockers or other transformer effects How? 2nd edit Lest it not be obvious, the 10 units of noise added to wire A or wire B is probably pretty trivial compared with the thousands of units of noise already on the mains at the point of the wall socket, which will likewise not be removed by the balanced connection which is only protecting noise being ADDED to Wire B
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Post by pinkie on Jan 2, 2016 12:40:04 GMT
I have posted this before, but I find this a very useful explanation of what a balanced CONNECTION does. I use it as an aide memoire when trying to do the algebraic proof of why noise on the input to the connection is NOT rejected .
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Post by Slinger on Jan 2, 2016 12:42:25 GMT
Now, I'm not saying that these comments wouldn't have been made if the BMU that is currently attracting fairly positive comments from those who have actually heard it wasn't made by NVA but it's certainly within the bounds of possibility. There is actually data to support the correlation between the OP and negative comments about NVA. Of course I'll back-pedal like buggery if anyone suggests that this is an anti-anti NVA comment. I'm just generalising. It could have been posted by anyone who hadn't heard the BMU a BMU.
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Post by pinkie on Jan 2, 2016 12:49:11 GMT
Now, I'm not saying that these comments wouldn't have been made if the BMU that is currently attracting fairly positive comments from those who have actually heard it wasn't made by NVA but it's certainly within the bounds of possibility. There is actually data to support the correlation between the OP and negative comments about NVA. Of course I'll back-pedal like buggery if anyone suggests that this is an anti-anti NVA comment. I'm just generalising. It could have been posted by anyone who hadn't heard the BMU a BMU. How is a question about how something works a negative comment? The question applies to balanced power. How a balanced connection can remove noise on the input. That has absolutely nothing to do with NVA. It is a generic question about the technology.
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Post by John on Jan 2, 2016 12:52:51 GMT
I guess it how you came in at the time on the intial thread So lets keep this clean everyone
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Post by terrybooth on Jan 2, 2016 13:02:02 GMT
The question about balanced mains and the question about a balanced connection are different and require difference answers.
A balanced signal cable is part of a system which uses differenct electrical circuits to treat the signal and cannot be treated separately from that system. You can't plug a balanced cable into an unbalanced socket (physical connection differences notwithstanding) without using an signal converter - a balun.
Balance Mains converts N=0vAC and L=240vAC to N=-120v and L=+120vAC via two coils from a transformer. Since the differential between N and L is still 240vAC, it can be used by anything, within the design tolerance of the transformer itself, which requires a 240 vAC electrical input. A balance mains converter is logically separate from the electrical system it feeds.
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