I don't want to single anyone out, but all this talk of transformers, and how amplifers work is a bit misleading.
What actually happens is this . . .
Amplifiers are modulated waveform DC devices, designed to deliver the required power into a specific load impedance, usually nominally 8 ohms.
Forget about the AC mains side of things for a moment.
A music waveform of 1v peak will therefore deliver 1/8 watts peak into that load. A 10v peak will deliver 8 watts, and a 50v peak will deliver 40 watts.
If the load falls to 2 ohms a 50v peak will deliver 160 watts, and a 100v peak will deliver 320 watts. Providing the power supply can supply the current required and not 'clip' the voltage.
Now let us consider where the amp gets its power from.
It does not directly use the mains supply, it actually draws it's power from a bank of reservoir capacitors, which must be big enough to supply the peak demand for the duration required (usually very short).
The music waveform is such that the average power requirement is maybe only 5 or 10 watts, even with 'audio compression' employed.
All that we require from the mains is a charging circuit designed to charge the capacitors on a continous basis, to keep them topped up.
So, it may be seen how a 1 amp fuse in the mains lead might be easily big enough to supply a 300 watt amplifier.
In these circumstances (music waveforms) you may realise that RMS ratings mean very little when discussing audio amplifiers, and the 50Hz mains sine wave is merely rectified to provise a low, DC charging circuit to keep the power supply reservoir capacitors topped up, which are the real souce of power, which is only required on the basis of a music (with peaks) waveform.
Hope this helps.
JC
What actually happens is this . . .
Amplifiers are modulated waveform DC devices, designed to deliver the required power into a specific load impedance, usually nominally 8 ohms.
Forget about the AC mains side of things for a moment.
A music waveform of 1v peak will therefore deliver 1/8 watts peak into that load. A 10v peak will deliver 8 watts, and a 50v peak will deliver 40 watts.
If the load falls to 2 ohms a 50v peak will deliver 160 watts, and a 100v peak will deliver 320 watts. Providing the power supply can supply the current required and not 'clip' the voltage.
Now let us consider where the amp gets its power from.
It does not directly use the mains supply, it actually draws it's power from a bank of reservoir capacitors, which must be big enough to supply the peak demand for the duration required (usually very short).
The music waveform is such that the average power requirement is maybe only 5 or 10 watts, even with 'audio compression' employed.
All that we require from the mains is a charging circuit designed to charge the capacitors on a continous basis, to keep them topped up.
So, it may be seen how a 1 amp fuse in the mains lead might be easily big enough to supply a 300 watt amplifier.
In these circumstances (music waveforms) you may realise that RMS ratings mean very little when discussing audio amplifiers, and the 50Hz mains sine wave is merely rectified to provise a low, DC charging circuit to keep the power supply reservoir capacitors topped up, which are the real souce of power, which is only required on the basis of a music (with peaks) waveform.
Hope this helps.
JC
CJSF said:
The output transformer in the amp 'transforms' the high voltage low current mains supply to low voltage high current output to the speakers.
Assuming no losses, volts in multiplied by current in = volts out multiplied by current out. So a 22 volt 10 amp output could be obtained from a 220 volt supply and only pull 1 amp from the mains. As power = volts x amps that would be 220 watts; again assuming no losses, which there invariably are.
Somewhere on your amp there should be a label with, amongst other things, the maximum power consumption. If you divide that number (maybe 200 Watts or something) by the mains supply voltage in your country you'll get the maximum current that your amp will pull from the mains.
Ref. my earlier post mentioning CNOevils amp; if it's solid state as opposed to your valve amp, it'll be different. My mistake.
My observations were not particularly directed towards you Paul, and I can see that you were considering the 'output' transformer in his valve amp.
That component, of course, has little or nothing to do with the 'mains supply' side of things.
JC
That component, of course, has little or nothing to do with the 'mains supply' side of things.
JC
Covenanter
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Overdose said:
Yes the little electrons get scared when they hear the loud noises and stay in their holes.
Chris
PS Just my little joke for the quantum physicists here.
jcbrum said:
Thank you JC, I get the picture, so all that stuff about big fuses and the like is rubbish? . . . The amp has its own power supply via capacitors, makes sence to even an electronics dimwit like me. Therefor the issue is how the elctronics in the mains conditioner affect what goes into the capacitors, in my case according to my ears, it works wonderfully well, especialy at £28 . . . I'm happy, no hang ups, I will get on and enjoy my music even more than before . . . :rofl:
CJSF
That's ok CJSF, you're welcome, and thanks for the info.
It makes me wonder why the manufacturers of your amplifier didn't see fit to incorporate such a low cost and essential bit of equipment into your equipment in the first place.
I hope you have written to them with a stern rebuke, telling then they don't know how to design properly, and until you discovered the defect, it spoiled the sound quality to which you would otherwise have been entitled.
If only HiFi manufacturers would allow their customers to design their electronics.
JC
It makes me wonder why the manufacturers of your amplifier didn't see fit to incorporate such a low cost and essential bit of equipment into your equipment in the first place.
I hope you have written to them with a stern rebuke, telling then they don't know how to design properly, and until you discovered the defect, it spoiled the sound quality to which you would otherwise have been entitled.
If only HiFi manufacturers would allow their customers to design their electronics.
JC
professorhat
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alchemist 1
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Covenanter
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CnoEvil said:Covenanter said:
Enough to dim the lights in the house when it's switched on.
I have the same problem with my electric toothbrush. But it's got fantastic rhythm and the air around the bristles has to be seen to be believed. Of course I only wash it in lark's tears but I expect everybody does that. Mind you I'm thinking of going back to rubbing my teeth with charcoal because the organic fluidity of the movement is so much more satisfying. I am struggling however to find charcoal recovered from the funeral pyres of Icelandic virgins as WDHP (WhatDentalCleaningProducts) recommends.
Chris
Covenanter said:
I'm delighted to hear that your teeth aren't in a jar beside your bed (next to your wig?) and need a toothbrush with the power of a welder to clean them. Does your hairbrush double as an industrial sander and run on three phase? 😉 :shifty:
Sad aint it JC . . . 'non so blind as them that wont see' . . . or is that . . . 'deaf as them that wont hear'?
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CnoEvil said:
I wish I could claim all my teeth are my own but they are (at great expense) still in my head. What's left of my hair is still on my head too but it's more silver now than its original blonde. I think I'll buy one of those amps that apparently need 13 amp fuses as that means it's consuming about 3kW and I can dry my clothes by hanging them in front of it rather than using a tumble dryer. (I looked at the pdf of the manual and it proves you can fool more of the people more of the time than even a cynic like me thought.)
Chris
Covenanter said:
Hmmm who do I believe, a company that produces high quality Hi Fi products for decades and has its own very active R&D dept, or someone who advertises for AVI and other so called armchair " experts " on this site
Hmm decisions decisions..................
Sospri said:
HaHa, you can believe who you like, Sospri, it's your funeral. :doh:
BTW, AVI have produced high quality HiFi products for decades, and do continue to do so. Martin Grindrod is one of the best electronics design engineers in the world. Trained and qualified in the Defence industry, and the founder and Chief Engineer, of AVI.
He doesn't believe in 'foo' either.
But don't let that influence you. 😉
JC
Certainly will not jc,
I would not trust any manufacturer that is too scared to submit its products for review, it tells its own story..............
I would not trust any manufacturer that is too scared to submit its products for review, it tells its own story..............
Sospri said:
Sadly, Sospri, If you are making an inference to AVI, you utter untruths. I don't know whether you do it deliberately, to be mischievous, or even malicious, or whether you are simply confused.
In any event, you are making your own assertions, which I am sure will be given whatever credibility, it deserves.
I'm surprised that this forum encourages such mischief.
JC
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