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Post by Deleted on Dec 24, 2014 12:46:10 GMT
OK, so my Musical Fidelity A3.2Cr power amp (which is fab BTW) emits a mains-like hum for about the first 3 to 4 seconds following switching on. The hum is louder to start with and then fades away over those 3 seconds or so.
Not asking for a remedy as it's always done it. But I'm curious as to WHY it does it?
The/my A3.2cr has the choke-regulated power supply that MF are keen on, along with a physically large transformer and plenty of capacitors (upgraded by John Samson, ex MF guy). The hum is from the amp, not the speakers.
Merry Christmas / Happy Mid-Winter,
Derek
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jc
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Post by jc on Dec 24, 2014 14:08:11 GMT
A lot of amps do this. It's just that inrush of electricity when you first switch on, it takes several seconds for the power supply to stabilise, the transformer(s) vibrate momentarily during this time.
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Post by Deleted on Dec 24, 2014 15:04:27 GMT
OK, so my Musical Fidelity A3.2Cr power amp (which is fab BTW) emits a mains-like hum for about the first 3 to 4 seconds following switching on. The hum is louder to start with and then fades away over those 3 seconds or so. Not asking for a remedy as it's always done it. But I'm curious as to WHY it does it? The/my A3.2cr has the choke-regulated power supply that MF are keen on, along with a physically large transformer and plenty of capacitors (upgraded by John Samson, ex MF guy). The hum is from the amp, not the speakers. Merry Christmas / Happy Mid-Winter, Derek Why are you turning it off? An amp is better off being left on all the time, sounds much better too.
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Post by Deleted on Dec 24, 2014 20:40:50 GMT
You know, for many years I never switched my entire system off. That was when it was based around my MF B200 and it always sounded better when the amp had been on for 30 to 40 mins. Until then it 'spoke Japanese' to my ears. A bit hard and mechanical.
Laterly, with my 3.2cr, I also kept my system warmed up and ready for listening. Then, one day, I plugged in one of those gadgets that show electricity consumption and my total system came in at around 350 Watts per hour. For reasons of economy I decided against having it on day after day - and noticed no change in sound quality when used from cold.
But, an amp switched on all the time lasts longer? Fewer stresses and strains as it heats up, cools down, repeatedly?
Derek
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Post by Deleted on Dec 26, 2014 11:48:20 GMT
You know, for many years I never switched my entire system off. That was when it was based around my MF B200 and it always sounded better when the amp had been on for 30 to 40 mins. Until then it 'spoke Japanese' to my ears. A bit hard and mechanical. Laterly, with my 3.2cr, I also kept my system warmed up and ready for listening. Then, one day, I plugged in one of those gadgets that show electricity consumption and my total system came in at around 350 Watts per hour. For reasons of economy I decided against having it on day after day - and noticed no change in sound quality when used from cold. But, an amp switched on all the time lasts longer? Fewer stresses and strains as it heats up, cools down, repeatedly? Derek I agree with everything you say with one exception. To leave an amplifier on permanently costs around 2p a month more than turning it off and then on. That figure is according to Which magazine and What Hi-Fi agree It will last longer too as turning electrical items on and off is quite disturbing to them. In the last twelve years I have used one amp, while the family have used seven different vacuum cleaners! Also it is recommended 'never' turning off your modem nor computer, it breaks them.
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Post by Deleted on Dec 26, 2014 11:49:08 GMT
A lot of amps do this. It's just that inrush of electricity when you first switch on, it takes several seconds for the power supply to stabilise, the transformer(s) vibrate momentarily during this time. The inrush of electricity almost costs the same as not turning the amp off in the first place.
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Post by Deleted on Dec 26, 2014 11:50:24 GMT
My last quarterly Electricity bill was £75 and I never turn off the amp, CD player, Freeview box, computer nor modem. That comes to 81.5p per day.
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jc
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Post by jc on Dec 26, 2014 12:22:50 GMT
Although I agree with your electrical facts and general points for on/off stresses on equipment, there is one fly in the ointment. All those electrolytic capacitors inside have limited life. Usually 10,000 hours or less. This is the downside, your equipment degrades faster and should be serviced to keep it tip top, otherwise you suffer breakdown due to the failing capacitors. Basically you can't win!
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Post by Deleted on Dec 26, 2014 17:31:20 GMT
Although I agree with your electrical facts and general points for on/off stresses on equipment, there is one fly in the ointment. All those electrolytic capacitors inside have limited life. Usually 10,000 hours or less. This is the downside, your equipment degrades faster and should be serviced to keep it tip top, otherwise you suffer breakdown due to the failing capacitors. Basically you can't win! 10000 hours of superior sound quality sounds like a win to me.
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jc
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Post by jc on Dec 26, 2014 21:19:16 GMT
10000 hours of superior sound quality sounds like a win to me. 10,000 hours = 1year, 1 month, and 20 days. That's a short life for the power supply section. In reality, of course, it's not that short as in idle the caps don't have a hard life but still...
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Post by Deleted on Dec 27, 2014 8:33:33 GMT
10000 hours of superior sound quality sounds like a win to me. 10,000 hours = 1year, 1 month, and 20 days. That's a short life for the power supply section. In reality, of course, it's not that short as in idle the caps don't have a hard life but still... You will just have to take my word for this, but I assure you my A3 amp has been on for ten years and only turned off when I went into hospital or on holiday (6 times). It sounds fluid rich and transparent and if it failed tomorrow I would still think I'd had a splendid service out of it.
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