Sigurd Ruschkow said:
Fair enough, I thought I'm missing something here. Unfortunately I highly doubt I am a good medium for any audio subjective testing, I must be either stone deaf or an incurrable skeptic. That's why I was asking if you are aware of any conclusive 3rd party testing on this topic.
Regarding "dielectric vibrating" and hence a modulation of inter-wiring capacity (which obviously would be increased by any dielectric with a constant larger than 1 (vacuum), and 1.00059 (clean and dry air at 20 degrees centigrades and 1 atm pressure) this is called electrostriction. It is typical for polar dielectrics and it is proportional to the square of the polarization P. A quick check in the literature shows that a polyurethane elastomer (a polar material specially designed for electrostriction driven devices) constricts about 1um for each 10V applied across a 1mm layer, or about 0.1% Considering two wires insulated by 1mm of such a material (which is already a stretch, nobody is using this as an electrical insulator) with a dielectric constant of 4 and separated by 10mm or air, subject to 100V, a quick check shows a capacitance variation order of magnitude of about 0.00001% Is this significant? I don't know, but I know that the dielectric constant of air varies approximative linear with the pressure, with a slope of about 0.05%/atm.
Which makes moving your amp from the ground floor to the 10th floor, or the pressure differential created by a room fan that kicks in, way more significant than the electrostrictive effect in the amp wiring. And again, this is for a very polar material that was never intended for wire insulation.
Hi burbeck,
The only "mistake" I made was in believing that most other situations were protected similarly to my own situation and that of my neighbours, but in referring to conversations with my brothers, I accepted that this was not the case.
However, for posters to suggest that *always* or a similar term the UK domestic ring mains are protected only by 30A, or 32A, is clearly not correct either.
Whatever, what is the problem with you reading what I said *correctly*, both at the time I originally commented on what "I" had done, and have since made absolutely clear about plug fuses?
I did NOT and still do NOT recommend UK readers to do this for themselves, and I even included a warning over the consequences. How much clearer can that be even to those who didn't bother to read what I said in the first place properly.
When other posters have also stated that they have removed ALL of their fuses, throughout, which I have suggested against more than once, why pick on my carefully-worded remarks?
Maybe we should stop posts which I have seen before where posters say they handle exceedingly high voltages (sometimes as part of their work) as this is probably far more likely to be dangerous.
I am not sidstepping anything, but I do expect readers to refrain from jumping in to criticise anyone at the first opportunity, when they appear unable or unwilling to *properly* read what I have said.
Regards,
The only "mistake" I made was in believing that most other situations were protected similarly to my own situation and that of my neighbours, but in referring to conversations with my brothers, I accepted that this was not the case.
However, for posters to suggest that *always* or a similar term the UK domestic ring mains are protected only by 30A, or 32A, is clearly not correct either.
Whatever, what is the problem with you reading what I said *correctly*, both at the time I originally commented on what "I" had done, and have since made absolutely clear about plug fuses?
I did NOT and still do NOT recommend UK readers to do this for themselves, and I even included a warning over the consequences. How much clearer can that be even to those who didn't bother to read what I said in the first place properly.
When other posters have also stated that they have removed ALL of their fuses, throughout, which I have suggested against more than once, why pick on my carefully-worded remarks?
Maybe we should stop posts which I have seen before where posters say they handle exceedingly high voltages (sometimes as part of their work) as this is probably far more likely to be dangerous.
I am not sidstepping anything, but I do expect readers to refrain from jumping in to criticise anyone at the first opportunity, when they appear unable or unwilling to *properly* read what I have said.
Regards,
hi bobken,
because your "carefully worded remarks" are wrong, and are likely to be followed by inexperienced DIYers. even suggesting that you remove the fuse from a UK mains plug is foolhardy.
give it up bob, stop side stepping, you know it makes sense
because your "carefully worded remarks" are wrong, and are likely to be followed by inexperienced DIYers. even suggesting that you remove the fuse from a UK mains plug is foolhardy.
give it up bob, stop side stepping, you know it makes sense
AndrewT said:
No, I am not trying to be obtuse in any way and I didn't even realise that "AC" had been missed out, although again this is entirely beside the point.
Anyone simply following the bold instructional advice to use a 275v (AC or not!) Transzorb *without the most vital comment that there is a difference between RMS & peak voltages* will likely be in serious trouble, as I pointed out.
These devices are not listed in the same way as the vast majority of devices, and as we are apparently expected to be absolutely 'water-tight' with all comments (let alone specific advice) to ensure that even if comments are *misread* no innocent person could ever get into difficulties, my comments were essential in my view.
Nowhere in the data sheets, nor in any suppliers catalogues I have seen is this unusual but vital point made, and generally when prospective users are searching for such devices, it would be accepted that a 275v listed device would be OK on our mains, but this is obviously not so.
Incidentally, I am not in the least "annoyed", but I am absolutely dismayed at what is going on, which is hardly any encouragement to bother with any such matters in the future.
What a waste of good media space this continually 'moving-target' of criticisms has taken up, especially when others have suggested more risky, or inadequately-explained matters.
Regards,
I know absolutely nothing about British codes and law, but I do know that in the US, if one bypasses local fuses in mains-connected equipment, your insurance is generally void. And you are liable for any consequential damage. Bad juju, and a risk I would never take for the sake of something with (harrumph) doubtful and (absolutely) unproved sonic benefit.
Can we stop this safety thing yet? OK, we need fuses.
I think I can hear the dull thud in the distance of John Curl banging his head on the wall.......
I think I can hear the dull thud in the distance of John Curl banging his head on the wall.......
Bobken said:
Hi Bob, sorry for off-topic. Could you please give me some pointers re. this kind of insurance cover - by email if possible (info (at) ant-audio.co.uk).
Thanks
Alex
x-pro said:
Hi Alex,
I would dearly like to help, but for now I have decided not to give ANY more "pointers" to anyone I don't know personally (either on or off this Forum), perhaps for obvious reasons, and I prefer to keep my mail address to myself, similarly.
However, as a generalisation, when I converted my property to have an added office/workshop area where I do my development work, I approached the Insurance Company directly about this change.
I don't know how much it influenced matters, but my wife then worked for this Company whose Head-Office is local to us, and I found dealing with their Actuary directly, to be a painless exercise.
He was very interested in what I was doing, and quickly understood the position after looking at our property and talking to me about my intentions. I have always avoided all Insurance Brokers or other intermediaries throughout my life, and I think this helps a lot as others can tend to cloud or exaggerate issues/risks.
The result was an alteration to the various terms etc., but the increase in premium wasn't colossal to my relief, in spite of the fact that I have some serious equipment (insured separately) including lathes, milling machines, welding gear, compressors etc., and a whole host of electronic equipment here.
These instances are always judged individually, I was advised, so any more specific details would not be likely to help you very much, anyway. I hope that knowing this may be of some value to you, and I trust you will understand my stance in this matter.
Regards,
Surge protection
I looked at the datasheet for the transorbs Transorb (like all small component suppliers they have been swallowed up by Vishay) and the parts are interesting but not up to surge protection use. For example the one that would be the typical US application has a peak surge current rating of 5A. The equivalent MOV has a rating of 3000A. 5A would be fine for the small spikes from a relay switching on or off or a vacuum cleaner motor but useless against lightning or similar transients on the line. If you have some impedance in series (an LC filter) it would be OK but not enough if you live in a lightning prone area (Colorado, Florida, South Africa I'm told) or are near heavy industry. And in any case you need some type of fusing/current limiting.
They might be fine on the secondary of a power transformer to protect the rest of the circuitry.
A lot of modern electronic equipment have MOV's on the power input to protect switching supplies. All of these in your house add up to help reduce the potential surges in the house so protection is not as necessary as it once was but there is still value in a good surge suppressor.
I looked at the datasheet for the transorbs Transorb (like all small component suppliers they have been swallowed up by Vishay) and the parts are interesting but not up to surge protection use. For example the one that would be the typical US application has a peak surge current rating of 5A. The equivalent MOV has a rating of 3000A. 5A would be fine for the small spikes from a relay switching on or off or a vacuum cleaner motor but useless against lightning or similar transients on the line. If you have some impedance in series (an LC filter) it would be OK but not enough if you live in a lightning prone area (Colorado, Florida, South Africa I'm told) or are near heavy industry. And in any case you need some type of fusing/current limiting.
They might be fine on the secondary of a power transformer to protect the rest of the circuitry.
A lot of modern electronic equipment have MOV's on the power input to protect switching supplies. All of these in your house add up to help reduce the potential surges in the house so protection is not as necessary as it once was but there is still value in a good surge suppressor.
Hi Demian,
Of course you are quite right in stating the limitations of these devices, especially where lightning-strikes etc. go, but for HQ audio applications we don't use them for their originally-intended purpose, like several other components/materials. Dealing with substantial strikes/surges is not what any manufacturer I am aware of provides for normally in domestic audio gear, but I am happy to be corrected here.
I am sorry if this wasn't made absolutely clear, but as Sigurd apparently uses these devices, I am sure if he reads this he will confirm that they do have a beneficial effect on the sound by clipping the hash on mains supplies, providing quieter backgrounds etc.
You should try them sometime, perhaps, as their unique benefit is that they don't have any adverse sonic effects whilst they are doing their job.
30 years ago, MOVs etc. used for the same purpose by 'enthusiasts' were fashionable over here, but whilst they did their primarily-intended duty, I (and some others, I guess) found they had unwanted side-effects on the sound at the same time, regrettably.
I carried out many listening trials on all then-known candidates for reducing mains noise, including some massive Telecom spark-type devices, but none of the alternatives passed the 'sonically benign' test where unwanted side-effects were concerned, and most of them deteriorate over time with the number & amplitude of surges.
I guess that with the march of time even better devices may have surfaced since some 25 yrs, ago, but I am not aware of these specifically, and I don't comment on matters of which I have no experience, except through clearly-stated 'guesswork'.
Incidentally, the subjective 'benefit' afforded by multiple Transzorbs is also cumulative, so I use them everywhere. Although I won't divulge who, I know that Transzorbs are used as the main 'active element' in more than one UK made 'mains cleaner' on sale to the public.
Regards,
Of course you are quite right in stating the limitations of these devices, especially where lightning-strikes etc. go, but for HQ audio applications we don't use them for their originally-intended purpose, like several other components/materials. Dealing with substantial strikes/surges is not what any manufacturer I am aware of provides for normally in domestic audio gear, but I am happy to be corrected here.
I am sorry if this wasn't made absolutely clear, but as Sigurd apparently uses these devices, I am sure if he reads this he will confirm that they do have a beneficial effect on the sound by clipping the hash on mains supplies, providing quieter backgrounds etc.
You should try them sometime, perhaps, as their unique benefit is that they don't have any adverse sonic effects whilst they are doing their job.
30 years ago, MOVs etc. used for the same purpose by 'enthusiasts' were fashionable over here, but whilst they did their primarily-intended duty, I (and some others, I guess) found they had unwanted side-effects on the sound at the same time, regrettably.
I carried out many listening trials on all then-known candidates for reducing mains noise, including some massive Telecom spark-type devices, but none of the alternatives passed the 'sonically benign' test where unwanted side-effects were concerned, and most of them deteriorate over time with the number & amplitude of surges.
I guess that with the march of time even better devices may have surfaced since some 25 yrs, ago, but I am not aware of these specifically, and I don't comment on matters of which I have no experience, except through clearly-stated 'guesswork'.
Incidentally, the subjective 'benefit' afforded by multiple Transzorbs is also cumulative, so I use them everywhere. Although I won't divulge who, I know that Transzorbs are used as the main 'active element' in more than one UK made 'mains cleaner' on sale to the public.
Regards,
Bobken, I can feel your frustration, as I have had to: 'suffer the slings and arrows of outrageous criticism' (thanks Willie) many times on this website and 3 others over the decades.
Much of this 'criticism' comes from poor reading of the text, but then it must be VERY CLEAR , if we are to avoid other people from following suit (in their own way) and causing accidents.
While I appreciate your detailed input, others may read it the wrong way or incompletely. For example, I first thought that you avoided all protection devices. On rereading, I saw that this was not the case, but it was implicit rather than explicit in your text, to the casual reader (like me), and if I don't pick it up, think about others with less command of English, safety or engineering considerations.
Personally, I know that fuses are nonlinear, and many people can hear them in their system. I don't need any 'stinkin' double blind tests, either, to assert that as a knowable, if not a fact. How we deal with it may depend on how sensitive we are with our own audio playback system, but we cannot omit a serious regard for safety.
Now that we know you better, it is obvious that you have covered all the angles, but others, in their enthusiasm to improve their system, may not do so.
I still like to parallel the concept of automotive air cleaners. Some we know are just an afterthought of the manufacturer, and removing them, especially if they are somewhat dirty and clogged over time, might improve performance. Many teenaged kids (including me at one time) are tempted to throw them out and not put in an improved replacement. One good dust storm, and your engine life is seriously reduced, for one. Another gets another 50,000 miles without any problems.
It is the same with fuses or circuit breakers, and I think that we should still discuss which circuit breakers and fuses work best and in what positions for product safety. I know from experience that each one of us is blind-sided in some way, just like the post from Damien this morning brought forth a weakness in using a Transzorb exclusively as protection. It will work, but it will self-destruct working alone. This is valuable input and a reminder to all of us.
Much of this 'criticism' comes from poor reading of the text, but then it must be VERY CLEAR , if we are to avoid other people from following suit (in their own way) and causing accidents.
While I appreciate your detailed input, others may read it the wrong way or incompletely. For example, I first thought that you avoided all protection devices. On rereading, I saw that this was not the case, but it was implicit rather than explicit in your text, to the casual reader (like me), and if I don't pick it up, think about others with less command of English, safety or engineering considerations.
Personally, I know that fuses are nonlinear, and many people can hear them in their system. I don't need any 'stinkin' double blind tests, either, to assert that as a knowable, if not a fact. How we deal with it may depend on how sensitive we are with our own audio playback system, but we cannot omit a serious regard for safety.
Now that we know you better, it is obvious that you have covered all the angles, but others, in their enthusiasm to improve their system, may not do so.
I still like to parallel the concept of automotive air cleaners. Some we know are just an afterthought of the manufacturer, and removing them, especially if they are somewhat dirty and clogged over time, might improve performance. Many teenaged kids (including me at one time) are tempted to throw them out and not put in an improved replacement. One good dust storm, and your engine life is seriously reduced, for one. Another gets another 50,000 miles without any problems.
It is the same with fuses or circuit breakers, and I think that we should still discuss which circuit breakers and fuses work best and in what positions for product safety. I know from experience that each one of us is blind-sided in some way, just like the post from Damien this morning brought forth a weakness in using a Transzorb exclusively as protection. It will work, but it will self-destruct working alone. This is valuable input and a reminder to all of us.
Hi John,
I couldn't agree more with the majority of your comments, but being a bit old-fashioned, perhaps, I believe in some consistency in life.
Accordingly, if all these adverse comments are as sincere as they purport to be, and there is absolutely no personal bias involved, wouldn't you expect that those involved recently might perhaps also make some comment on a couple of other posts which could hardly be misread by anyone, and which will affect everyone, rather than merely UK members?
As you accept, I did not mislead anyone into doing anything silly unless they didn't read what I said carefully, but 2 other posters (who I have nothing against) very clearly stated in just a couple of lines or so that they used NO fuses anywhere.
I find that a real puzzle, and you certainly commented to one poster at the time, but I just wish we could move on from this.
From my viewpoint, it now seems risky bothering to discuss anything, whether I am careful or not with what I have to say.
Regards,
I couldn't agree more with the majority of your comments, but being a bit old-fashioned, perhaps, I believe in some consistency in life.
Accordingly, if all these adverse comments are as sincere as they purport to be, and there is absolutely no personal bias involved, wouldn't you expect that those involved recently might perhaps also make some comment on a couple of other posts which could hardly be misread by anyone, and which will affect everyone, rather than merely UK members?
As you accept, I did not mislead anyone into doing anything silly unless they didn't read what I said carefully, but 2 other posters (who I have nothing against) very clearly stated in just a couple of lines or so that they used NO fuses anywhere.
I find that a real puzzle, and you certainly commented to one poster at the time, but I just wish we could move on from this.
From my viewpoint, it now seems risky bothering to discuss anything, whether I am careful or not with what I have to say.
Regards,
Just a thought...john curl said:
This seems like an engineering opportunity.
Why not discuss alternative solutions?
Can't we isolate this at the power supply?
john curl said:
I’ve been reading the fuse/circuit breaker/no protection posts. I made some back-of-the-envelope calculations and my conclusion is that you should not even think of trying to use your service panel circuit breaker for protecting your preamp. One of the posts said that it was his project and he could do what he wants in his own home. Try explaining that to your insurer should a fault in your preamp burn your house down as a result of a fire due to lack of UL ac input protection. Remember, the blowtorch and other high end equipment is designed to remain on continuously.
Let’s assume the dc rails are +/-30V, and the operating power is 35W. Let’s also assume we use a 50VA transformer to reduce the internal temperature rise. The secondary winding might be 44 VCT at 1.14A. With an 87% efficient transformer the full load 120 vac primary rating is 0.48A.
Running 1.4 Tesla flux density and 400 circ. mils/amp current density in the wire we can use AWG-27 primary wire and AWG-22 secondary wire. The primary resistance is about 11.4 ohms and the total secondary resistance is about 1 ohm. The primary-referred equivalent secondary resistance is 7.7 ohms since the resistance/impedance is proportional to the turns ratio squared.
Now let’s put a dead short on the secondary, possibly due to a diode or bulk filter cap failure, and see the effect on the transformer primary current. With the excellent primary-secondary coupling and high transformer inductances afforded by a toroid or R-core, we could get a sub-cycle peak current of at least 10-times rated current. This peak would depend upon where on the ac line half-cycle the fault occurred, and thus the amount of inductive energy stored. For the worst case, there would be a slewing of the ac current that results in a dc offset that decays with time as the core is demagnetized from the minor hysteresis loop caused by the initial current peak. This would be followed by a continuous current of 6.28 amps if the transformer doesn’t saturate or just saturates at the peaks (120Vac/19.1 ohms), to 10.5 amps if the transformer fully saturates (120Vac/11.4 ohms).
Without any protective devices, this represents between 750 and 1260 watts continuously cooking the internals of your preamp. Your 15 amp service panel circuit breaker and the near-zero impedance of the 120V ac line (remember that 200 A service entrance breaker) will happily provide this “fault” power forever. The AWG-27 copper wire in the preamp power transformer can probably carry the fault current for quite a long time before melting open. This is your only "fuse" and the weakest-link wire temperature would be greater than 1000 deg C. Fire is inevitable.
If the fault is on the primary side of the preamp power transformer, the peak let-through current could be kiloamps before the 15 amp house circuit breaker trips (to save the AWG-14 house wiring, NOT your preamp). In this case there will be an explosion inside your preamp for sure.
Now let’s look at several possible input protection devices. The simplest, cheapest protection remains the fuse. A 1 amp time delay line fuse would open in less than 120 msec and can withstand 10 kiloamps of fault current. With large filter caps and no charge current limiting you might need a larger ampere fuse, and the fusing time would increase proportionally. The cold resistance of a 1 A time delay fuse is about 200 mohm and the full load drop is about 400 mV. Those concerned with modulation of the ac line voltage due to cyclical fuse thermal resistance variation can compute the dB attenuation required by a common-mode choke/filter, but even if it was the full 400mV it would be below -50dB. The level of garbage on the ac line is much higher than fuse modulation.
A relay would provide a very fast 10 msec dropout time, and you can make a very accurate overcurrent trip detector circuit for it. You would have to provide some means to latch the trip so it would not reclose into the fault when the power supply collapsed from the fault. The relay could also provide a delay turn-on and a current limiting resistor to limit the capacitor charge current. But the relay contact drop at rated current is 100mV so, while the silver-cadmium oxide contacts are more massive than a fuse wire, you still can't totally eliminate thermal modulation.
A small 1A thermal circuit breaker could also provide input protection. I have used the Airpax ATR11 series with success in test equipment. A 1 amp circuit breaker would take 4.5 sec to trip at 6.28 A. In theory it would take 1 sec to trip at 10.5 A, but this exceeds the upper limit of 8 x rating, so a circuit breaker of less than 6 amps on the primary side might weld rather than trip.
I just looked and the Airpax seems to have a 1000A interruption capacity. Where is the 8X limit from?
Using transorbs to lower line noise can be good but if the voltage spike is limited its turned into current and the current and its associated magnetic field need to be managed. The energy never evaporates (there is a basic physical law about that I think) so you should be locating the Transorb well upstream from the protected device. In fact a series damping resistor may help reduce the effective noise and ringing on the power line. Unless the resistor is of very special construction it will evaporate if hit with a real surge, but so will the transorb.
If I can get some time and some sample transorbs I'll test this.
If I can get some time and some sample transorbs I'll test this.
OT:
I worked in a military light truck project many years ago. We had trouble passing the EMP test. This electromagnetic pulse induced such high currents in the inductive engine speed/crankshaft position sensor (used by the engine ecu) that the ignition module was destroyed each time we tested. No VDR, shielding etc. cured this. We measured 100eds of ampere induced!
A transzorb in parallel to the sensor near the ECU solved the problem, and only a transzorb diode withstood several NEMP pulses.
After the pulse, the engine still stopped but could be restarted.
Since then, I never forgot what a transzorb diode is capable of.
NB, my Junghans radio controlled watch passed away at the first pulse
I worked in a military light truck project many years ago. We had trouble passing the EMP test. This electromagnetic pulse induced such high currents in the inductive engine speed/crankshaft position sensor (used by the engine ecu) that the ignition module was destroyed each time we tested. No VDR, shielding etc. cured this. We measured 100eds of ampere induced!
A transzorb in parallel to the sensor near the ECU solved the problem, and only a transzorb diode withstood several NEMP pulses.
After the pulse, the engine still stopped but could be restarted.
Since then, I never forgot what a transzorb diode is capable of.
NB, my Junghans radio controlled watch passed away at the first pulse
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