alansawyer said:
Thank you for the offer, but, being charitably-minded, they are already destined for a local school.
After a spring-clearout of my workshops, there will be several thousand unwanted components and semi-conductors etc., which I have been advised they will make good use of.
Regards,
AndrewT said:
As a school Governor for 8 years, I can assure you they will not have to do this every day. They will have budgets to buy materials and will buy parts that are certified RoHS compliant.
They will not have the capability or time to check packets of old components to determine whther they were made lead free or not.
BTW - did you mean "techy" http://www.thefreedictionary.com/techy or techie ?
alansawyer said:
The offer has been arranged through the school's science lab technician who is a close neighbour of mine, and I am sure he knows what he is doing.
For what it is worth, even before my teenage years we would scrounge small lead offcuts from the local building-site and melt them down with a paraffin blowlamp to make fishing weights. I can even recall what lead tastes like as there was no such thing as 'health hazards' in those days, and I am still around in my late '60s!
Regards,
Bobken said:The offer has been arranged through the school's science lab technician who is a close neighbour of mine, and I am sure he knows what he is doing. - I would ask him if he knows of RoHS and WEEE directives before assuming this.
For what it is worth, even before my teenage years we would scrounge small lead offcuts from the local building-site and melt them down with a paraffin blowlamp to make fishing weights. I can even recall what lead tastes like as there was no such thing as 'health hazards' in those days, and I am still around in my late '60s!
Regards,
Because you are still alive, should we assume you have the same smug complacement attitude that you seem to show about lead poisoning to speed limits, drink driving laws, seat belts and all the other "nanny state" laws that stop us killing children?
The health hazards were there, but you were uneducated in their existence.
Kind of like de-earthing your system.
alansawyer said:
Hi,
I am not looking for trouble here, but I didn't ask you to make *any* assumptions although you appear to have already done so when suggesting that I am "smug" and "complacent" (I assume that is the word you intended, but it doesn't include the letter 'M'), neither of which is the case.
I see no reason for such remarks which could be considered offensive, and I simply reported a situation which occurred in my past. Why you should attempt to 'extrapolate' my remarks to include deliberately putting children in jeopardy for *any* reasons, I cannot imagine.
As the neighbour concerned is responsible to the school for purchasing such materials for their use, I have every reason to believe that he is entirely competent to do so in accordance with any current requirements.
I don't intend to waste any more off-topic bandwidth on JC's thread to comment any further on this issue.
Regards,
Gentlemen and any ladies,
Going back a bit (before Alan's deep Lead paranoia), we were speaking of detecting differences in a given listening situation?
I'd like to suggest two things, in the event they are not in evidence or unknown to the general readership regarding this topic.
Thing 1) dectecting an "event" in a recording is one thing
Thing 2) detecting an overall "effect" or "change", "variation" within a system is another
Since the brain compensates for the deficits in what we are listening to, as much as it can, it is easier to detect Thing 2 when it happens to be a system that is intimately well known to the listener - eg. your own system.
Regarding Thing 1, I have related the anecdote regarding the George Bolet recording with Dutoit (sp?) where someone whacks the music stand rather vigourously during a passage. I can only detect the whack less than 50% of the time! I KNOW it is there (approximately - which is a part of the detection pie) - but still fail completely to hear it, even when I want to hear it in order to point it out to a visitor! It's not any 100dB down.
Now wait a second, before you think it makes your case. Otoh, changes that alter the overall "presentation" those being of the Thing 2 nature, are almost always immediately obvious.
So, change within vs. change of. Very different.
If there is any interest by-and-by I can post the recording's title and you all can go out and get it and try to hear the instrument stand being wacked. You get to hear one of the absolute best pianists of the modern era playing two well known ruskie compositions at a virtuoso level as a bonus.
I'd also like to mention that if anyone here has not done so, put on some pink noise and listen to your system. Do something to it that will adjust some known parameter a small amount, like a slight shelf or boost to the HF (just an example) and see if you can detect it when someone clips in the parts and unclips it. Try to see how small of a change (like the R in series with the C across the speaker terminals??) you can still detect.
Now try it with any program material you want. I doubt if you can detect the change that was clearly audible with pink noise. My experience is that when I get a speaker running best with pink noise, (and any other measurements to help) that it usually ends up sounding "easier to listen to" even when the change itself is really not detectable as a discrete difference auditioning regular program material.
Anyone here do this sort of thing before??
Pavel, I'm goona go out on a limb and guess that the turquoise trace is a Class A with EC of some sort?? That's an impressive trace!! Yellow is not too shabby either...
_-_-bear
Going back a bit (before Alan's deep Lead paranoia), we were speaking of detecting differences in a given listening situation?
I'd like to suggest two things, in the event they are not in evidence or unknown to the general readership regarding this topic.
Thing 1) dectecting an "event" in a recording is one thing
Thing 2) detecting an overall "effect" or "change", "variation" within a system is another
Since the brain compensates for the deficits in what we are listening to, as much as it can, it is easier to detect Thing 2 when it happens to be a system that is intimately well known to the listener - eg. your own system.
Regarding Thing 1, I have related the anecdote regarding the George Bolet recording with Dutoit (sp?) where someone whacks the music stand rather vigourously during a passage. I can only detect the whack less than 50% of the time! I KNOW it is there (approximately - which is a part of the detection pie) - but still fail completely to hear it, even when I want to hear it in order to point it out to a visitor! It's not any 100dB down.
Now wait a second, before you think it makes your case. Otoh, changes that alter the overall "presentation" those being of the Thing 2 nature, are almost always immediately obvious.
So, change within vs. change of. Very different.
If there is any interest by-and-by I can post the recording's title and you all can go out and get it and try to hear the instrument stand being wacked. You get to hear one of the absolute best pianists of the modern era playing two well known ruskie compositions at a virtuoso level as a bonus.
I'd also like to mention that if anyone here has not done so, put on some pink noise and listen to your system. Do something to it that will adjust some known parameter a small amount, like a slight shelf or boost to the HF (just an example) and see if you can detect it when someone clips in the parts and unclips it. Try to see how small of a change (like the R in series with the C across the speaker terminals??) you can still detect.
Now try it with any program material you want. I doubt if you can detect the change that was clearly audible with pink noise. My experience is that when I get a speaker running best with pink noise, (and any other measurements to help) that it usually ends up sounding "easier to listen to" even when the change itself is really not detectable as a discrete difference auditioning regular program material.
Anyone here do this sort of thing before??
Pavel, I'm goona go out on a limb and guess that the turquoise trace is a Class A with EC of some sort?? That's an impressive trace!! Yellow is not too shabby either...
_-_-bear
I'd like to know what people think about the differences in low level detail retrieval of systems and how much easier it is to spot differences between systems using this criteria. It gets back to Pavel's plots and like Bear, I thought the light blue (Cyan?/Turquoise?) trace to be exemplary but hadn't a clue what topology it was except it & yellow were probably Class A - the other two I thought had GNFB?
I suggested on the measurements thread that Pavel play a little game with us
I suggested on the measurements thread that Pavel play a little game with us
) think that the Feng Shui is more important but nobody else seems too.
maxpou said:
Hi,
Prior to installation I always check the toriodal transformers I use (specially made up with a GOSS circumferential band to reduce unwanted emissions) with a hand-held device used for detecting such radiated fields. This device has both an LED and a varying-level sonic output, and when swapping over the two primary leads (when the transformers are properly-loaded and powered-up) the difference is at least an order of magnitude, although this is an objective assessment and not from precise measurements.
When I first tried this test a long while ago, I confess to being surprised at this degree of change, because toroidal transformers are always claimed to exhibit low radiated fields, and this general claim is for transformers without the added GOSS band (and an additional grounded electrostatic interwinding shield which I also specify, although this shouldn't affect the issue so much).
Interestingly, 'R-core' transformers exhibit much less difference in 'radiation' when tested and connected-up either way.
Regards,
Bobken said:
Hi Bobken,
This is really quite interesting. Is the hand-held device something like a coil, where radiated magnetic emissions will cause an induced voltage that is measured, probably with significant bandwidth?
I take it that you are referring to swapping the Hot and Neutral lines going into the transformer?
What do you think the mechanism is?
Do you think the emissions that are changing depending on ac "polarity" are a result of the transformer action alone, or more a result of rectifier current spikes on the secondary (which, of course, will have effects that are conveyed to the primary).
Thanks,
Bob
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