dcathro Posted May 28, 2020 Posted May 28, 2020 Hi Andy, Is that separate orange and yellow wires or an orange and red striped wire? Cheers David
dcathro Posted May 28, 2020 Posted May 28, 2020 56 minutes ago, Steffen said: Neither can I, apart from the (low) chance of adding noise, which should be easy to detect. I don't know WHY either!
Warren Jones Posted May 28, 2020 Posted May 28, 2020 20 hours ago, dcathro said: Hi Andy, You have me confused how does your transformer have four secondaries? In mine there is a red and a black wire going in (240v and 0v), and yellow, brown and blue out (45, 0, 45) So I can connect the red and black to either 240v or 0v, and the yellow and blue to either AC side of the bridge. In my preamp the transformer secondaries are not colour coded (both black), but the two orientations sound different. Cheers David Because Andy's TX has 2 separate windings, depending on how you connect the windings you can get a + and - DC voltage or parallel the windings for double the secondary current. It is important if you parallel the windings to make sure you have the winding polarity correct. Winding polarity has nothing to do with voltage polarity as AC has no polarity only Active and Neutral.
andyr Posted May 28, 2020 Posted May 28, 2020 58 minutes ago, dcathro said: Hi Andy, Is that separate orange and yellow wires or an orange and red striped wire? Cheers David Separate, David. AIUI - yours is a 'centre-tapped transformer' ... mine isn't. Andy
MTsoul Posted May 28, 2020 Posted May 28, 2020 I'm going to just jump back in with an update: Yamaha referred me to Electronics Today who told me over the phone it was all perfectly normal to have power running through the front panel and the RCAs. When I explained the issue with the Stax he told me to take the Yam back to A2A and have them plug it in. I'm going to do some testing with different sockets and powerboards tonight. If that is inconclusive, I'm taking the yam and the stax to a friends place and trying there to eliminate any issues in my apartment wiring. If there is still problems I'm going to Electronics Today so he can see it for himself.
dcathro Posted May 28, 2020 Posted May 28, 2020 45 minutes ago, Warren Jones said: Because Andy's TX has 2 separate windings, depending on how you connect the windings you can get a + and - DC voltage or parallel the windings for double the secondary current. It is important if you parallel the windings to make sure you have the winding polarity correct. Winding polarity has nothing to do with voltage polarity as AC has no polarity only Active and Neutral. Hi Warren, the secondaries will be 180deg out of phase?
dcathro Posted May 28, 2020 Posted May 28, 2020 14 minutes ago, andyr said: Separate, David. AIUI - yours is a 'centre-tapped transformer' ... mine isn't. Andy OK andy, understood. How do you have them connected to the amp? are they paralleled?
andyr Posted May 28, 2020 Posted May 28, 2020 34 minutes ago, dcathro said: OK andy, understood. How do you have them connected to the amp? are they paralleled? No, one secondary feeds the diode bridge on the +ve DC rail - the other one feeds the diode bridge on the -ve DC rail. Andy
Warren Jones Posted May 28, 2020 Posted May 28, 2020 34 minutes ago, dcathro said: Hi Warren, the secondaries will be 180deg out of phase? The phase will not change it's fixed by the mains. What will change is the magnetic field. Someone posted earlier about adding and subtracting in a TX. It is the magnetic field that adds and subtracts and it does influence secondary voltage UNDER CERTAIN CONDITIONS like paralleling windings. It has no effect if the TX is standalone.
dcathro Posted May 28, 2020 Posted May 28, 2020 1 minute ago, Warren Jones said: The phase will not change it's fixed by the mains. What will change is the magnetic field. Someone posted earlier about adding and subtracting in a TX. It is the magnetic field that adds and subtracts and it does influence secondary voltage UNDER CERTAIN CONDITIONS like paralleling windings. It has no effect if the TX is standalone. Yes, but if your going to parallel them, then you would have to ensure that the phases match.
Warren Jones Posted May 28, 2020 Posted May 28, 2020 1 minute ago, dcathro said: Yes, but if your going to parallel them, then you would have to ensure that the phases match. We might be talking cross purposes here. Phase is the relationship of the AC wave to zero degrees. This is fixed by the power generation system. The only way to alter AC mains phase is to shift it with a capacitor. Like in an AC induction motor that uses a start capacitor to phase shift so the motor starts. Transformer winding polarity is the physical way the wire is wrapped around the former, this effects the rotation direction of the magnetic field around the TX former. This explains it reasonably well
dcathro Posted May 28, 2020 Posted May 28, 2020 3 hours ago, andyr said: No, one secondary feeds the diode bridge on the +ve DC rail - the other one feeds the diode bridge on the -ve DC rail. Andy Hi Andy, I have always used a center tapped transformer, with a single bridge to get V+ and V-. I understand that with your arrangement you use one output winding to get V+ and the other to get V- Thinking about swapping the wires, you would keep the same wires for each bridge, and swap them over. If you know that the transformer is wound in the same orientation as you have it connected, such as: orange at the 'top' of the first winding yellow at the bottom of the first winding black at the 'top' of the second winding red at the bottom of the second winding Then you should have two possible alternatives: the one you have (Orientation #1) or the one I think you meant to be #4 yellow to the 'top' of the +ve DC rail diode 'diamond' orange to the bottom of the +ve DC rail diode 'diamond' red to the 'top' of the -ve DC rail diode 'diamond' black to the bottom of the -ve DC rail diode 'diamond'. If you don't know the orientation of the windings, then you should try all four alternatives (or 8 if you swap the inputs ) e.g. if the transformer is wound yellow at the 'top' of the first winding orange at the bottom of the first winding black at the 'top' of the second winding red at the bottom of the second winding Then Orientations #2 or #3 would likely be better. Cheers David
dcathro Posted May 28, 2020 Posted May 28, 2020 3 hours ago, Warren Jones said: We might be talking cross purposes here. Phase is the relationship of the AC wave to zero degrees. This is fixed by the power generation system. The only way to alter AC mains phase is to shift it with a capacitor. Like in an AC induction motor that uses a start capacitor to phase shift so the motor starts. Transformer winding polarity is the physical way the wire is wrapped around the former, this effects the rotation direction of the magnetic field around the TX former. This explains it reasonably well Hi Warren, we are talking about different things. The two ends of a center tapped transformer winding are out of phase from each other. Cheers David
dcathro Posted May 28, 2020 Posted May 28, 2020 (edited) Hey @andyr have you got a circuit diagram for your power supply. because I am not sure that what I said above is correct. It could be with your transformer that there is only one way to connect the secondaries. Or it could be that there are other ways to connect that may not have the same effect as in my case. Cheers David Edited May 28, 2020 by dcathro
andyr Posted May 28, 2020 Posted May 28, 2020 22 minutes ago, dcathro said: Hey @andyr have you got a circuit diagram for your power supply. No, sorry - only as a PDF - which won't post here. Andy
dcathro Posted May 28, 2020 Posted May 28, 2020 3 hours ago, andyr said: No, sorry - only as a PDF - which won't post here. Andy Understood. You can convert the pdf to a jpeg then crop the picture to only show the transformer and diodes. But I understand if you don't want to do that.
andyr Posted May 28, 2020 Posted May 28, 2020 Just now, dcathro said: Understood. You can convert the pdf to a jpeg then crop the picture to only show the transformer and diodes. But I understand if you don't want to do that. No, David - very happy to do that ... just that my (lack of!) technical skills don't let me! (Convert pdf to jpg, that is.) Andy
dcathro Posted May 28, 2020 Posted May 28, 2020 Hi Andy, Just google it. There are free online programs that will do it - very simple. e.g. https://pdf2jpg.net/ Cheers David
stereo coffee Posted May 28, 2020 Posted May 28, 2020 (edited) To say there is no effect of which way Active and Neutral attach to a rectifier, is to agree with transformer theory.... ie plainly there is no difference. However we assume just like an amplifier to speakers that attach to it, that transformers are sufficient in current capability to drive any given load.... and usually they are. What is not being seen is the load transformers actually do drive, and therefore the effects from that load on the transformer caused by the rapid switching of diodes - each containing strange artifacts like dark current which is reverse bias leakage current, and the strange lazy way we have come to use rectifier circuits, which I think may contain clues as to why some are swapping active for neutral. If this swapping is to be done at all, it should be done on the secondary side of the transformer winding, simply for safety sake alerted to here: https://sound-au.com/articles/mains-safety.htm Almost every bridge rectifier either grounds the negative anode side of the diode bridge to create a positive voltage, or grounds the positive side of the bridge the cathode, to create a negative voltage, The other is a center tap ground on the transformer, with the diode bridge using each half.... messy but works, .... but separate bridge rectifiers for each voltage rail are much better. Its a lazy way of doing power supplies regardless, as the bridge directs full current of whichever polarity to be used in a DC current source manner to the needed polarity and views the anodes (describing a needed positive voltage) of the diode bridge as a ground. I would hazard at a guess there are then small differences how each transformer polarity is utilized, because there are delays with DC circuitry as current sources, compounded by capacitance charging and discharging. This might begin to explain preference for how the secondary transformer winding relates to the primary winding with polarity. Current being drawn, may not coincide properly with the transformer addressing the bridge rectifier. If so swapping secondary wiring is a band aid solution, but if found to be beneficial a full examination of the circuitry needs to determine Why... not just think you have it solved. The other way is Yes difficult, but would see just the amount of current needed by the supply being controlled by - in the case of a positive supply the anode of the bridge - .... rather than just grounding, the required load is then actually determined by the circuit addressing the rectifier anode. The risk with this is instant polarity swap, but the advantage if it can be done, is far better use of the rectifier- when = time , and by exactly how much is needed. Edited May 28, 2020 by stereo coffee
andyr Posted May 28, 2020 Posted May 28, 2020 (edited) 10 hours ago, dcathro said: Hi Andy, Just google it. There are free online programs that will do it - very simple. e.g. https://pdf2jpg.net/ Cheers David Thanks, David - very handy utility. Here is the PS schematic; it's a very cunning, low-ripple PS designed for a Class A amp (the load can draw up to 6a, continuously). My question to you - in relation to your comment that the orientation of the secondary windings affects the sound - is, given I have orange / yellow and black / red wires ... which colour wire should go onto the: J1 spade J2 spade J3 spade, and J4 spade? Thanks, Andy Edited May 28, 2020 by andyr
dcathro Posted May 29, 2020 Posted May 29, 2020 Hi andy, Thanks for you diagram. So my answer above is correct. keep you current secondary configuration, or invert both the secondaries (i.e. swap round the orange with the yellow and the red with the black). Off course you can also try swapping round just one secondary at a time. Then off course you can try each of these with the primary inputs swapped. If your going to try it, I would do it with some friends (ears you trust) to get a consensus on any differences. Cheers David
MLXXX Posted June 18, 2020 Posted June 18, 2020 On 28/05/2020 at 9:53 AM, aussievintage said: How the heck this can affect the sound of the amplifier I don't know, but I can see that there may be some physical differences as above, with different connections. I have to agree, aussievintage, that it is not clear how the sound of the amplifier would be affected. And of course before pondering that question in depth, it could be useful to identify which particular equipment has given subpar performance with a particular active-neutral connection orientation. * * * In many parts of the world, non-earthed plugs (as used to power double-insulated equipment from a power point on the wall) can be inserted in either orientation. The manufacturer should design their product to perform properly whichever way the plug happens to be inserted into the power point by the customer. The opening post appears to take the view there will be an audible difference if the mains active and neutral connections are interchanged. (A few posters to this thread have indeed reported hearing a difference. However, others have reported hearing no difference.) I would suggest that failure to hear a difference with particular equipment if the active and neutral connections are swapped does not necessarily imply that the listener has "cloth ears". A simple and plausible explanation would be that there happens to be no audible difference, for the particular equipment, in these circumstances.
Red MacKay Posted June 18, 2020 Posted June 18, 2020 Well, it's time I chime in... IMO, on most gear the polarity of the AC active and neutral can give quite a drastic difference in SQ, but not everything. Some seem to not mind too much, but others... Many years back on advice from someone I trusted, I bought a Graham Slee phono. It had a two way radio AC plug for the linear p/s. When I plugged it in - what a bag of shite! The sound was recessed and just p*x. In disgust, it quickly got flicked back into it's box and chucked into the spare room. Fast forward 6 months and I thought it was time to move it on, but being paranoid and not wanting to sell something that was faulty, I thought I'd give it another go. All plugged in and yep - it was still p*x. Then I thought, "what's it like if I plug it in the other way round". So I did that and bugger me - it was sounding pretty darn good. Completely different and way fuller in sound. I swapped it back as used previously for another crack, and it returned to p*x. So on that linear supply it made a huge difference! The question was asked why manufacturers clearly don't mark it - I ask the same. Another instance was when I borrowed a US male plug AC Shunyata mains cable from the boys at AV Reference in Ringwood. As I run only AU plugs here at my place, I plugged the US cable into an adaptor and hey presto we have a goer. Well I tried that cord for over two weeks and it was terrible. I even ran a fan on it 24/7 for 5 days to put some miles on it ( it was new) and that didn't help either. When I returned it, I explained my dissatisfaction to David, only to have him clearly explain that the US and us here in Australia are at opposites with our wiring of the active and neutral and simply plugging it into a straight adaptor was destined for bad SQ. I had never heard of it!!! When I later checked - David was 100% correct. So how many others in Audio Land out there do not realise this? A lot of people I know us US plugs - just how many of them are out of phase with the incoming AC? The easiest way I found to check plugs is by using a three light tester. You simply plug it into the female end of a plug and see which lights come on - simple. I also have a Lampizator Switch/ Filter Box which has four oulets that are individually switched with 3 position switches, allowing the easy change of phase to see which sounds best. When I can find the tester I mentioned previously, I will post a pic. Just my 2 cents - ymmv. 2
attunement Posted January 29, 2021 Posted January 29, 2021 Referencing the post above, attached is a scan of the pamphlet accompanying the Graham Slee PSU1 Linear Power Supply that states "Changing mains 'polarity' may make an audible difference". I have always been content with my MM Accession Phono Preamp's performance, so to test this out I rotated the inlet, and yes, I found the sound tinnier, thinner and not as full-bodied, and so I reverted back to my original satisfactory placement. As Red notes above "The question was asked why manufacturers clearly don't mark it".
attunement Posted March 9, 2021 Posted March 9, 2021 Following on from the previous post, these comments from Graham Slee's amplification forum explain his reasoning for using a two-way AC plug. suede writes "Since I started caring more about quality sound reproduction or true HIFI about a year ago I have found that the most mysterious aspect is hands down the power or electricity bit. For instance changing the position of a power cord in the wall socket by 180 degrees (I live in Sweden which has two pin mains outlets so this is possible) can have tremendous impact on the sound quality going from slightly boxy and a bit boomy to clear as day." Graham Slee replies "And this, ladies and gentlemen, is why we use the old fashioned and completely non-trendy two way figure of 8 PSU1 mains inlet (which means it has to be class-2 and class-2 means double insulated/no earth)."
Recommended Posts