Noisy transformer buzzing

You are probably getting DC offset on your mains. Try an Emotiva CMX2 power conditioner. It blocks DC voltage. I had the same problem with a Yamaha amp once and it cleaned it right up. BTW, there are lots of things plugged into household electrical that can throw off DC.
 
I am already using a stabilizer with the system as I dont trust the electricity where I reside. I have a pioneer a-9 with toroidal transformer. That works perfectly though with or without my stabilizer . I think its something else

Appreciate the tip though
 
I am already using a stabilizer with the system as I dont trust the electricity where I reside.
Didn't you say in post #15 you weren't using a power conditioner?

Please try it without anything but the power cord between the amplifier and the wall socket. See if it still gets hot and/or the humming changes.
 
Didn't you say in post #15 you weren't using a power conditioner?

Please try it without anything but the power cord between the amplifier and the wall socket. See if it still gets hot and/or the humming changes.
I am sorry I thought the power conditioner is different form a stabilizer . Or is it the same ?. I use a stabilizer . But now since since I am trying to find a solution it is being tested directly Connected to the wall socket . Same results directly to the wall or with the stabilizer the transformer in the amplifier gives same results I.e with or without the stabilizer .
 
I am sorry I thought the power conditioner is different form a stabilizer . Or is it the same ?. I use a stabilizer . But now since since I am trying to find a solution it is being tested directly Connected to the wall socket . Same results directly to the wall or with the stabilizer the transformer in the amplifier gives same results I.e with or without the stabilizer .
Excellent -- that eliminates the stabilizer as a problem. Again, I suggest trying to identify the secondary windings of the transformer and disconnect them, to see if there's undue load on the transformer. If it still hums and heats, then the transformer is likely faulty.
 
Another thing: What is the voltage at your wall plug?

I just looked at the schematic for the Pioneer A-7, and it has a switchable line voltage selector. Make sure it's set to match your line voltage.
 
Another thing: What is the voltage at your wall plug?

I just looked at the schematic for the Pioneer A-7, and it has a switchable line voltage selector. Make sure it's set to match your line voltage.
It is yes I am sure . I live in India right now ,220v is what we get here and that switchable voltage switch can't accidentally be switched to 110 (just saying ) other wise things would have blown long back
 
It is yes I am sure . I live in India right now ,220v is what we get here and that switchable voltage switch can't accidentally be switched to 110 (just saying ) other wise things would have blown long back
The schematic I've got indicates switchable 220 or 240, not 110.
 
I have 110v 120v 220v and 240v . It's all faded and rusted on those numbers unfortunately
 

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That might have once read 220. :)

The level of rust is somewhat ominous. Hopefully that's just exterior damage, but if it got wet inside and corroded the transformer, that might account for the symptoms.
Yes ever since I moved the system from the gulf back in 2008 it slowly caught problems . I was not aware of moisture during the rainy season so used to keep the windows open and the system was kinda near the window . So I guess the moisture got it . By the time I realized it was late, had got many rust spots . But inside is clean like 90% thankfully. Now I keep it covered
 

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I noticed something. Most of the rust is on the right side from behind the system ( the transformer is in the right side too ) . Check out the pic . Do you think at that time the moist got into the transformer due to rains ? as I remember that side was near the window and here in India it's immense moisture during the rains from July -oct
 

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Thanks allot for the tips . Is it safe in terms of heat dissipation? Cause doesn't the chassis help transfer heat from the PT ?
Anyway sound s mechanical yes but it is coming from right inside the PT as the freq of the sound it high , not the big hum but high buzz . By default there is a hum when u switch on the amplifier when it's in cool state . That low hum is fine .(and it takes 25 mins for that high freq sound to get loud gradually with no load also

You will understand from my video

Allan- That buzz is actually the higher harmonics of the 60 Hz line frequency. It sounds like internal damage. Either the laminations are buzzing or the windings are. I used to work in a transformer factory and one of my jobs was to quiet down buzzing transformers. We used to hammer a piece of hard, fish paper between the laminations and the coils until they quieted down. Then the transformers was varnished, vacuumed to get the air bubbles out and baked (to a golden brown). Try this, get in there with a screwdriver and tighten all the screws holding the laminations together, that might be enough to quiet it. If not, look for a replacement tranny.
 
Thanks triode . That was some good information. I will try to screw it tight . Will find appropriate flat head screws and tighten it up

I already tried with wedge screws meaning heads were a wedge shape on one side and nuts on the other side . Made it extremely tight . There was no difference in sound
 
I already tried with wedge screws meaning heads were a wedge shape on one side and nuts on the other side . Made it extremely tight . There was no difference in sound
Wedge-head screws will directing a considerable amount of force outward rather than compressing the laminations, as the wedge tries to enlarge the hole it's in. Flat-head screws will direct all the force into compressing the laminations, but if it's rusted internally and/or has shorted and/or loose windings, that won't help.
 
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