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Old 14th December 2004, 01:56 PM   #11
rs1026 is offline rs1026  India
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Default No Diff

No difference its exactly same.Only thing is I have put everyhting into a metal box now before it was just lying on a piece of wooden board.
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Old 14th December 2004, 02:01 PM   #12
Electrons are yellow and more is better!
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I'm not totally convinced that this is all the truth. Can't you take picture?

Is it "soft" hum 50 Hz even with input shorted? Is it "hard" 100 Hz hum with lot's of harmonics.

50 Hz, problem with ground loops and the input.

100 Hz some trouble with your power supply and grounding technique.

Is it a stereo amp (yes), one transformer(yes) , same hum in both channels?

Is the transformer more near your Lm3886 now than before? (picking up magnetic field)
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Old 14th December 2004, 02:35 PM   #13
rs1026 is offline rs1026  India
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>>I'm not totally convinced that this is all the truth. Can't you take picture?

I dont have a Digicam thats the problem.


>>Is it "soft" hum 50 Hz even with input shorted? Is it "hard" 100 Hz hum with lot's of harmonics.

Its a soft hum not very loud.But it is noticeable.


>>Is it a stereo amp (yes), one transformer(yes) , same hum in both channels?

yes,It is a stereo amp.Single transformer.Yes the hum is same in both the channels.

>>Is the transformer more near your Lm3886 now than before? (picking up magnetic field)

Yes,Now its is very near one of the lm3886 chips.before everything was spread out.So could it be magnetic field?


Can I connect the PCB grounds,mains earth to a single point on a chasis??
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Old 14th December 2004, 03:36 PM   #14
Nuuk is offline Nuuk  United Kingdom
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Quote:
Can I connect the PCB grounds,mains earth to a single point on a chasis??
This is explained on the FAQ page! That's why I asked if you had read it.
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Old 15th December 2004, 08:23 AM   #15
Electrons are yellow and more is better!
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Default Re: ..

Quote:
Originally posted by rs1026

>>Is it "soft" hum 50 Hz even with input shorted? Is it "hard" 100 Hz hum with lot's of harmonics.

Its a soft hum not very loud.But it is noticeable.


>>Is the transformer more near your Lm3886 now than before? (picking up magnetic field)

Yes,Now its is very near one of the lm3886 chips.before everything was spread out.So could it be magnetic field?


Can I connect the PCB grounds,mains earth to a single point on a chasis??
Try to move the transformer, less hum?

A toroid can be placed very near the electronics but a EI core has much more magnetic leakage.
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Old 17th December 2004, 04:31 AM   #16
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If u cannot move the transformer away from the electronics, put one iron sheet covering over the transformer(s). Need not be air tight as ventilation is necessary. This helps a lot.

Gajanan Phadte
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