First Bear and I have been contacted to make a smaller version of the 'Wall of Sound'. Glad to know he is still alive.
I think I confessed that I missed the great testing of the big sound system at the Cow Palace. I believe I did hear most of it in one place in Santa Barbara.
I have to agree with SY that "language or approach" (to others) is exactly what gains you respect around here and am amazed that there are supposed adults here that don't believe this!
Another AMAZING behavior is the belief that every comment that isn't in favor of an idea is an attack on the person proposing it, and that any true attack or snide remark needs to be addressed or responded to.
Any gratuitous or offensive comment can be ignored, and the members here are generally clever enough to recognize pointless and mean spirited attacks for what they are. Then the poster of such looks like a fool, When there is a response, then both sides look like fools. This is basic stuff.
To assume that our members can't recognize someone being a jerk and who is being ignored for this reason, is a bit insulting to those members.. have some faith in their abilities..
Mark
I have to agree with SY that "language or approach" (to others) is exactly what gains you respect around here and am amazed that there are supposed adults here that don't believe this!
Another AMAZING behavior is the belief that every comment that isn't in favor of an idea is an attack on the person proposing it, and that any true attack or snide remark needs to be addressed or responded to.
Any gratuitous or offensive comment can be ignored, and the members here are generally clever enough to recognize pointless and mean spirited attacks for what they are. Then the poster of such looks like a fool, When there is a response, then both sides look like fools. This is basic stuff.
To assume that our members can't recognize someone being a jerk and who is being ignored for this reason, is a bit insulting to those members.. have some faith in their abilities..
Mark
If the wall of sound was used in the summer of '73 at RFK stadium, than I can vouch for it easily making it to the upper deck of center field. Can't remember much else, though. Except that it was stinking HOT that day, the field looked like an Indian reservation, smoke signals and all.
Oh, RIP Jerry Garcia and Marilyn Chambers.
Oh, RIP Jerry Garcia and Marilyn Chambers.
I was at the Cow Palace on that date, I'm pretty sure. First Bear introduced me to Ram Dass,backstage. Memorable event for me.
G.Kleinschmidt said:
Isolation transformers are also used in medical electronics. However, for safety reasons the secondary winding is NOT grounded. Instead, earth leakage detectors are used. If something goes wrong, either with the isolation transformer, or the PSU inside medical the equipment, you will get a warning. The patient however, isn't in danger because of double isolation. Only in the rare circumstance that the isolation of both transformers fail at the same time, the situation gets critical (though still not lethal as the equipment itself is grounded, of course)
Cheers,
Edmond.
AndrewT said:
Isn't the real trick that with the isolation transformer, the whole secondary circuit can float wrt earth? The danger is when the sec circuit has a potential wrt earth, and then if you touch some live wire while another part of you is in contact with earth, a dangerous current can flow.
But with the isolation transformer, ungrounded sec, there is NO potential between earth and any live wiring, so no dangerous currents can flow through your body.
Now, if you ground the tap on the secondary of the isolation xformer, you're back in the danger zone. Conclusion: do not ground the sec of the isolation transformer. Maybe ground it through a highish resistor so that it can not float too far from ground and shock you, but this resistor should be high enough to prevent lethal currents through the circuit live wire-resistor-ground.
Makes sense?
Jan Didden
Hi Jan, that seems logical.
It is obvious when applied to a single piece of equipment.
Does the situation change when the whole room's mains supply is isolated and all the equipment inside that room will share that isolated power ring?
What if some of the equipment is double insulated (no protective earth) and others have the earth pin connected to the conductive parts?
Where does the earth leakage (RCCB/GNFI?) detector go? before or after the isolation transformer?
I knew this should have been a separate thread.
It is obvious when applied to a single piece of equipment.
Does the situation change when the whole room's mains supply is isolated and all the equipment inside that room will share that isolated power ring?
What if some of the equipment is double insulated (no protective earth) and others have the earth pin connected to the conductive parts?
Where does the earth leakage (RCCB/GNFI?) detector go? before or after the isolation transformer?
I knew this should have been a separate thread.
@ AndrewT,
janneman just posted something.
I might add, that it is exactly the purpose to prevent dangerous current from flowing through a human body in any case/fault.
So normally every piece of gear should have its own safety transformer (see for example a lot of japanese gear that traditionally comes with a two pin mains plug).
Normally it should be avoided to connect two or more device to one safety transformer, but one way to deal with it would be a sort of equipotential bonding similar to that used in medical enviroment.
But this sort of installment has to be planned with care and should be done with professional expertise.
Easier and (for a diy approach much safer) would be to replace all transformers in the devices.
janneman just posted something.
I might add, that it is exactly the purpose to prevent dangerous current from flowing through a human body in any case/fault.
So normally every piece of gear should have its own safety transformer (see for example a lot of japanese gear that traditionally comes with a two pin mains plug).
Normally it should be avoided to connect two or more device to one safety transformer, but one way to deal with it would be a sort of equipotential bonding similar to that used in medical enviroment.
But this sort of installment has to be planned with care and should be done with professional expertise.
Easier and (for a diy approach much safer) would be to replace all transformers in the devices.
I might consider adding a 7kVA isolation transformer for the whole room.Jakob2 said:
I would never consider adding 20 to 30 isolation transformers for all the individual pieces of equipment.
It is exactly as syn08 posted; but normally a "i hear something" is treated in a very different way, as the poster has (at least 🙂 ) to provide a scientific double blind test for verification.
If a " i don´t hear something" poster would have to prove in exactly the same way, that he _really_ does not hear something in this case (but otoh proves that he is able to hear on a sufficient sensitivity level), the game would be more balanced.
And it would be much clearer that this burden of proof is in many cases quite over the top.
If the members of both camps would avoid any sarcastic remark and stick strictly to technical topics these threads would be much substantial.
And please remember that this debate is going on for at least 35 years and it isn´t very smart to treat the various ideas in exactly the same way as always.
Please just accept the potential possibility that others do really hear something; nobody has to believe that it is so, just that it might be so.
And if you hear something, just accept the possibility that it might be just an illusion. 🙂
Jakob2 said:
It might work if it was an industrial sensor to evaluate the result. As it is a human ear and brain, this approach would not work.
@ AndrewT,
i understand that, but one isolation transformer can´t help if in two devices a transformer leakage occurs (it may be unlikely but is possible), that would still be life threatening.
So, in your case it must be equipotential bonding after the isolation transformer as in medical enviroments, but at a first glance i don´t know if it is permitted for this sort of installment.
Professional expertise is required.
i understand that, but one isolation transformer can´t help if in two devices a transformer leakage occurs (it may be unlikely but is possible), that would still be life threatening.
So, in your case it must be equipotential bonding after the isolation transformer as in medical enviroments, but at a first glance i don´t know if it is permitted for this sort of installment.
Professional expertise is required.
PMA said:
Maybe it´s a misunderstanding.
Why shouldn´t it be possible to discuss for example a new (or old) error correction scheme even if one thinks that it might sound better and another one just likes it for intellectual reasons, but doesn´t believe that it leads to different sonic results?
Just accept the different motivation and avoid attacking it.
Jakob, someone claiming that perhaps a drug with a specific carbonyl functionality might be efficacious is very different than someone claiming to cure cancer by waving love beads.
if equipotential bonding were required for all the equipment in the room then it's a non starter. The earthed equipment can use the third pin for equipotential bonding but the double insulated have no convenient connection for this link. Even if the regs permitted it.Jakob2 said:
Any other views?
Jakob2 said:
Jakob, if I understand it correctly, this would be no problem *provided* one would work only with/at one equipment at the time, correct?
Jan Didden
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