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Post by Deleted on Oct 26, 2016 17:41:04 GMT
Interesting points here, having fitted a great many of these over the years with mixed results, Airlink I am not so sure of the quality these days. Recently went to a place that had fitted a 5Kv unit on separate spur with dedicated CU, funny thing is mains condition via the normal ring mains sounded better! In the above case I really do feel the gent has quite 'shite' incoming a/c, the BP helped in certain areas and was counter intuitive with others. He doesn't live at the then end of line or near industrial works. Other places BP works well providing it is installed properly. I would agree with Y on the need for a DC blocker on the Airlink equipment. Depending where you are in the country UK mains can deliver quite different results. ...and what do you think of simpler solutions such as using a DC blocker on its own, or going further (more expensive) with mains re-generators? Y As pinkie pointed out in his post after yours, I work suggest that around 60% of transformer noise is down to over saturation of the core caused by a lot of transformers being either 220 or 230Vac specified. Now the UK is rated at 230Vac if you bother to measure your own voltage I would suggest it will be between 236-247Vac. Now if you take a 220Vac tx with fairly tight internal regulation say 4% yet the tolerance will claim to be +/-10% so a theoretical 242Vac before it reaches its limit. Now Pinkie made a very valid point about the threshold before a TX starts to destabilize the generated field then starts the hum (mechanical) though it can manifest it self in other forms such an electrical buzz through the speakers. The point at which each tx starts to 'off' is different and the only way to tell in the real world is to use a Variac and high quality DVM and slowly wind up the voltage to the point at which the TX misbehaves. This can be on a 1-2Vac threshold depending on the tx tolerance and QUALITY. The products we have been designing recently use a genuine 240Vac cores, screened and potted with a real tolerance of +10% even the UK does have maisn voltages that high yet! The most I have measured has been 249Vac in London With regard to DC blockers, the UK does have a lot of 'rubbish' on the mains, Common mode, DC offset and harmonic noise, here at Music Towers I regularly obtain 1.3Vdc sitting on the mains, which is a far too much considering there should be Zero! A properly implemented DC blocker can help, but also it can add to the noise issues, depending on which bridges, snubbers and smoothing caps are used. On the subject of mains re-generators, I am not a big fan for audio, they do have a positive effect (if you have enough headroom) in that they do clean up the upper frequencies, lower the noise floor and deliver deeper and more detailed bass YMMV However there is always something not right about for myself, however a great many people do appreciate their affects. I am firm believer in mains being one of the key three factors to a quality audio system, as well as amplifier<> speaker impedance and foremost Room/Speaker interface. However if I take out one mains lead it makes a definite and repeatable change in my own system. In my experience I have yet to come across one solution that covers all aspects of incoming mains issues. I have demonstrated a small passive unit sat infront of a very well respected mains regeneration unit that made a very positive difference in many aspects of the sound quality, yet while still damn fine on its own does not offer the complete solution. One of the aspects of audio that still carries as much debate as which came first the rugby or the football
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Post by Sovereign on Oct 26, 2016 22:27:25 GMT
James - I enjoy your company, and listening to your music too. I have done so twice - and you were keen to extol not just your fine SECA amp, but the "mother trucker" BPS and other elements of your system (dedicated power spurs, power cables stolen from the Clifton suspension bridge - or at least capable of holding it up). On both occasions, you chose to demonstrate your system when it suffered from a loud hum on one channel (it might have been both channels the 2nd time - I forget). It seems odd that you apparently gain an important benefit from things like fuses and dedicated mains spurs, but are happy to tolerate loud hum for the purposes of show-casing your system. Don't worry - you are not alone, from green felt pen on cd edges through all manner of unobtainium constructed gizmo's , over 30 years I have found many examples of enthusiasm for "things" which give that niche inner circle acceptance, rather than sort the basics out first. Apart from the various "Musical" aspects of the equipment I choose and like, I look for undetectable noise - of any sort (I'm setting myself up for trouble when Kevin comes round, but what the hell). Partly that is down to the design of the products - partly to the manner of the installation. Balanced power can help with noise reduction - but is a fairly cack way of doing it (in terms of effectivenes in addition to any safety issues). And if noise reduction is achieved with balanced power, I understand that it indicates that there are deficiencies elsewhere in the total set up which are allowing ground noise to be coupled to the signal. I prefer to fix those (get mates to fix those). If you don't couple ground noise to the signal, then reducing the noise on the ground line is going to have no impact on noise! Regarding "installation", balanced interconnects make huge sense (potentially). This discussion re-started because Kevin noted to me that he recently auditioned equipment at another forum members which sounded really good to him, and was devoid not just of mains and other "gadgets", but any exotic connections. That matches my experiences that a good system doesn't need "the fiddly bits". And those obsessed with the fiddly bits often have systems I don't enjoy listening to as much as some others - or my own. Mike - As I pointed out to Wonky, he can very easily test that fuse idea of yours. I doubt I will get a dinner out of it though Hi Richard sorry for the delayed reply, I seem to be busier than ever these days. thanks for the flattery of my system. i think I've mentioned before, not sure. The hum you heard was from output transformers in my DIY DDDAC that I could never seem to get to work correctly, others have reported similar findings, take them out and all is as quiet as a mouse. im not part of the green felt tip gadget gang, I have carved my own path and my system is quite unlike any others here. there are no brand names in my system, as I have made everything myself.i was just pointing out that the bps discussion in the past has been circular and painful to read. Of course no offence intended. However I do find the topic of mains quite fascinating,
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Post by Deleted on Oct 27, 2016 6:53:57 GMT
Out of interest, how do mains regenerators (like the Power Inspired AG1500) compare with balanced mains supplies? Is this another "you have to try it for yourself" "upgrade"?
I am also intrigued about why mains supplies are talked about so much in HiFi. I would love to see if it made a difference to my system, as I know there is a small element of DC on my mains.
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Post by pinkie on Oct 27, 2016 8:06:45 GMT
James
No offence taken, and none intended on my part. I had already deleted another post because I realised I'm just not interested in discussing the subject.
The first time was the dac . The hum on the 2nd occasion was mainly due to capacitvely coupled mains from the power supply to the laptop. Running it on batteries, and some chassis earthing I think, dropped the hum significantly towards the end
I got lucky there - without any research or premeditation, I happened to buy a laptop with decent internal grounding - a Fujitsu Lifebook
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Post by Sovereign on Oct 27, 2016 8:47:51 GMT
Your right. It was the laptop charger, I only listen powered from the batteries. I forgot to disconnect the charger, when we did all was well.
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Post by MartinT on Oct 27, 2016 11:37:56 GMT
My mains in the old house regularly measured 252V, Tony. Remember your advice to drop the output voltage from the P10 to 230V? Worked a treat - better defined soundstage, quieter noise floor.
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Post by Sovereign on Oct 27, 2016 12:14:21 GMT
...and what do you think of simpler solutions such as using a DC blocker on its own, or going further (more expensive) with mains re-generators? Y As pinkie pointed out in his post after yours, I work suggest that around 60% of transformer noise is down to over saturation of the core caused by a lot of transformers being either 220 or 230Vac specified. Now the UK is rated at 230Vac if you bother to measure your own voltage I would suggest it will be between 236-247Vac. Now if you take a 220Vac tx with fairly tight internal regulation say 4% yet the tolerance will claim to be +/-10% so a theoretical 242Vac before it reaches its limit. Now Pinkie made a very valid point about the threshold before a TX starts to destabilize the generated field then starts the hum (mechanical) though it can manifest it self in other forms such an electrical buzz through the speakers. The point at which each tx starts to 'off' is different and the only way to tell in the real world is to use a Variac and high quality DVM and slowly wind up the voltage to the point at which the TX misbehaves. This can be on a 1-2Vac threshold depending on the tx tolerance and QUALITY. The products we have been designing recently use a genuine 240Vac cores, screened and potted with a real tolerance of +10% even the UK does have maisn voltages that high yet! The most I have measured has been 249Vac in London With regard to DC blockers, the UK does have a lot of 'rubbish' on the mains, Common mode, DC offset and harmonic noise, here at Music Towers I regularly obtain 1.3Vdc sitting on the mains, which is a far too much considering there should be Zero! A properly implemented DC blocker can help, but also it can add to the noise issues, depending on which bridges, snubbers and smoothing caps are used. On the subject of mains re-generators, I am not a big fan for audio, they do have a positive effect (if you have enough headroom) in that they do clean up the upper frequencies, lower the noise floor and deliver deeper and more detailed bass YMMV However there is always something not right about for myself, however a great many people do appreciate their affects. I am firm believer in mains being one of the key three factors to a quality audio system, as well as amplifier<> speaker impedance and foremost Room/Speaker interface. However if I take out one mains lead it makes a definite and repeatable change in my own system. In my experience I have yet to come across one solution that covers all aspects of incoming mains issues. I have demonstrated a small passive unit sat infront of a very well respected mains regeneration unit that made a very positive difference in many aspects of the sound quality, yet while still damn fine on its own does not offer the complete solution. One of the aspects of audio that still carries as much debate as which came first the rugby or the football Yes my mains would frequently measure in the very high 240's. I glad you made the points you did as it confirms my belief for good transformers. I personally think the ones off the shelf from Airlink and Farnel etc are poor and made down to a very cheap price. The iron of the toroid I use for my MTBPS (balanced mains) is over spec'ed for a 5kVa toroid to avoid saturation, and is correctly rated for 240v mains. it is bespoke and made to the highest spec possible. Same principle for the toroids I use for my Wonfor class A amp. I also use a DC blocker before my balanced toroid, not sure of its design and quality but I can only presume its good as it comes from Nick Gotham - Longdog Audio. Overall the MTBPS made a really pleasing difference to the sound quality of my hifi.
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Post by pre65 on Oct 27, 2016 13:13:31 GMT
So, would having a voltage dropper of some kind, set to 230v, be likely to be kinder to transformers ?
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Post by John on Oct 27, 2016 13:17:34 GMT
Yes was wondering this too
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Post by Deleted on Oct 27, 2016 13:24:57 GMT
Do any of these things (BMU, Regen, DC blocker, voltage dropper etc) potentially invalidate home or contents insurance?
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Post by pre65 on Oct 27, 2016 13:50:07 GMT
The BMU I tried did hum/vibrate a little when I tried it.
So, now I've ordered two 2.2R 100W power resistors to use on the BMU input.
Will try it and see what happens.
BTW Some (so called) 100W Arcol type resistors on Ebay are the same size (dimensions) as the 50W type, so I've ignored those.
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Post by Deleted on Oct 27, 2016 14:06:48 GMT
Do any of these things (BMU, Regen, DC blocker, voltage dropper etc) potentially invalidate home or contents insurance? If it is CE marked, then it should be fine.
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Post by pinkie on Oct 27, 2016 15:50:38 GMT
Do any of these things (BMU, Regen, DC blocker, voltage dropper etc) potentially invalidate home or contents insurance? Here in France just about anything POTENTIALLY invalidates your home insurance. Our local rugby first team coach is still waiting for a payout 9 months after his home burned down due to a "non code" junction in the main supply cable, even though the fire demonstrably wasn't of electrical origin. If they do - the issue is likely to centre around RCD's. I am not sure what the rules are in France (in terms of bringing historical installations up to modern spec). I know you have to do it if you rent a house, and I think it is part of the homebuyer pack when you sell one. But for our new install - each new circuit block has to be protected by an RCD . So we have new consumer unit in my garden office, fed from the main board in the house. The main board splits the incoming power to 3 sub boards effectively. Each has a 60 amp rated 30ma trip RCD. At the board in the office - even though it is itself protected by a 60 amp RCD there is a further 40 A 30ma RCD for all circuits here. BMU and Regens both have a transformer which physically isolates the output AC supply wires from the input AC supply wires. Accordingly the output supply will only have RCD protection for anything connected to it if there are RCD's properly fitted to its output. Some do, some don't. It would depend whether our local french code has the requirement in respect of all domestic usage, or just certain devices and circuits. It appears to apply to all items. The fact that the lack of the RCD may not have been responsible for the fire, won't wash over here if it can be identified as a faulty installation. I would have thought it was less likely to be noticed however on a portable device, than it would be if it were an installation hard wired into the house. I guess the best way to be sure is to ask your insurer for clearance - in writing. I would assume that if a qualified electrician approves the installation and certifies that it would prevent insurance being invalidated. I know that the US electrical code 2002 only permits installations (permanent installations) of balanced power in commercial situations and where used by qualified personnel. A lack of a fuse on the "other" live wire in equipment not specifically modified for balanced power would probably give them an excuse too. Again - if they spot it. Mind you - just so we know this is France - I have just been to my folder to check my insurance wording and found a "carte vert" with a windscreen sticker in it. This is car insurance and it is a legal requirement for that small square to be displayed in the windscreen - so I was a bit spooked to find it in the folder. It's for the ride on mower, which even though it will only ever be used in the garden, and never used on the road, has to have its own insurance policy here.
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Post by MartinT on Oct 27, 2016 16:55:42 GMT
BMU and Regens both have a transformer which physically isolates the output AC supply wires from the input AC supply wires. Careful - some BMUs, regenerators and variacs may use an 'auto-transformer' which does not isolate the windings.
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Post by Sovereign on Oct 27, 2016 17:26:11 GMT
BMU and Regens both have a transformer which physically isolates the output AC supply wires from the input AC supply wires. Careful - some BMUs, regenerators and variacs may use an 'auto-transformer' which does not isolate the windings. What's an auto transformer mate ?
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Post by MartinT on Oct 27, 2016 18:53:12 GMT
One where there is only one winding with taps.
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Post by pinkie on Oct 28, 2016 7:59:40 GMT
BMU and Regens both have a transformer which physically isolates the output AC supply wires from the input AC supply wires. Careful - some BMUs, regenerators and variacs may use an 'auto-transformer' which does not isolate the windings. That's interesting Martin. I confess I have limited detailed knowledge of these devices. Which ones use an auto transformer? (I guess some could use SMPS as well). I would have thought that the regeneration itself will isolate the output from the input. It would be an easy test - just check continuity between Neutral on the input plug with Neutral on an output socket. But not a test you can do with your P10, since it appears to use a big toroidal for its power supply - so they will be isolated. I would have thought that if there is continuity between input phase and neutral and output phase and neutral that RCD's on the input would continue to provide protection. But if anyone is anxious and fears RCD bypassing may affect insurance, it is easy to test RCD tester(I note the unit can't detect neutral and earth reversed, a fault I have had before, but on a pre-RCD protected board, since reversing neutral and earth trips an RCD (on the same circuit).
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Post by MartinT on Oct 28, 2016 12:31:34 GMT
Which ones use an auto transformer? (I guess some could use SMPS as well). I would have thought that the regeneration itself will isolate the output from the input. No idea of which models or whether any still exist, but it's possible to use an auto-transformer in a Variac type mode to adjust output voltage. Early devices (like big computer power supplies) were electro-mechanical in order to adjust the Variac continuously to regulate output voltage. I think most regenerators do use an isolating transformer but again it would be possible to create a regenerator which doesn't, so it's not an inherent characteristic.
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Post by pinkie on Oct 30, 2016 6:55:22 GMT
Which ones use an auto transformer? (I guess some could use SMPS as well). I would have thought that the regeneration itself will isolate the output from the input. No idea of which models or whether any still exist, but it's possible to use an auto-transformer in a Variac type mode to adjust output voltage. Early devices (like big computer power supplies) were electro-mechanical in order to adjust the Variac continuously to regulate output voltage. I think most regenerators do use an isolating transformer but again it would be possible to create a regenerator which doesn't, so it's not an inherent characteristic. Hmm. I think that is an inappropriate conclusion. My advice is that an auto-transformer would not be an appropriate or likely device for the battery charger /dc power supply elements of the inverter circuit. Where auto-transformers are used in ups it is for a "buck-boost" arrangement in circuit with the mains and inverter to use auto-transformer position adjustment to compensate for small voltage variations without draining the battery on the inverter circuit. Whilst theoretically it might be conceptually possible to build a regenerator with an auto-transformer in the inverter dc supply, in practice no such device exists, nor is likely to. Obviously if you can point me to a real actual regenerator of that type I would stand corrected. But in the absence of that it seems reasonable to state that a regenerator without its own rcd on the output will, like a bps without rcds on the output, cause there to be no rcd protection for anything plugged into it. Of course a regenerator would only require single pole output rcds, not dual pole ones, for equivalent protection to that provided by a normal consumer board, and doesn't have the extra live wire for internal equipment switching and fusing issues in any insurance claim scenario. Rcds
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Post by MartinT on Oct 30, 2016 7:33:49 GMT
I was talking theoretically, Richard. I don't know which models use what architecture. I do know about computer UPSs and I know some cheaper devices for the audio market are derived from computer designs so am just making an assumption.
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