allanmatters
Active Member
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Noisy transformer buzzing
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allanmatters
Active Member
I just discovered something on the base housing of the PT !!
I was playing around with the power transformer putting 4 pieces of hard rubbers to absorb the high sound etc under all four legs below. Still nothing. tried different ways positions etc. Still nothing . then I tried applying pressure like a good 20-22 lbs of weight with my thumb at the middle front of the PT with rubbers below under the legs. The noise went away substantially !.
So I decided to have a closer look at the PT from underneath. Somehow I flipped it carefully and found out the housing frame below (the same direction from the top where i had applied the pressure) which clips /holds the transformer tight had bent away from the lamination instead of inwards. I looked at the other housing frame behind and that was perfectly vertically sticking to the lamination's (bent inwards straight in parallel order/)
So the other side was not parallel to the lamination cause it was bent outwards a bit. I dont know how this happened cause I never took out the transformer for like 30 years for any reason. I tried to bend the housing frame inwards with a heavy plyer but its just so thick and tough. So i put a thin piece of wood below the housing frame and put all the screws and tightened it accordingly . This minimized 90 % of the high buzzing sound. I left 10% aside cause I dont get really annoyed with it and plus I am testing it out to see how long it can go like this as I am afraid I would bend the legs too much if I tighten it more.
I have attached some pics
I was playing around with the power transformer putting 4 pieces of hard rubbers to absorb the high sound etc under all four legs below. Still nothing. tried different ways positions etc. Still nothing . then I tried applying pressure like a good 20-22 lbs of weight with my thumb at the middle front of the PT with rubbers below under the legs. The noise went away substantially !.
So I decided to have a closer look at the PT from underneath. Somehow I flipped it carefully and found out the housing frame below (the same direction from the top where i had applied the pressure) which clips /holds the transformer tight had bent away from the lamination instead of inwards. I looked at the other housing frame behind and that was perfectly vertically sticking to the lamination's (bent inwards straight in parallel order/)
So the other side was not parallel to the lamination cause it was bent outwards a bit. I dont know how this happened cause I never took out the transformer for like 30 years for any reason. I tried to bend the housing frame inwards with a heavy plyer but its just so thick and tough. So i put a thin piece of wood below the housing frame and put all the screws and tightened it accordingly . This minimized 90 % of the high buzzing sound. I left 10% aside cause I dont get really annoyed with it and plus I am testing it out to see how long it can go like this as I am afraid I would bend the legs too much if I tighten it more.
I have attached some pics
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allanmatters
Active Member
System has been running for more than 3 hours now and it's literally silent as ever with that small piece of wood I stuffed at the bottom of the PT on one side . And of course adjusted the screws just right tight .
I cant believe it ! There is just a very tiny high treble buzz but it's barely heard or noticeable.. reminds me of the time I had put varnish to quiet it down(super quiet) .
Im only worried and hope the PT legs don't bend over time due to the wood piece acting as an obstacle to tighten the laminations from below in the middle , as this would gradually lead to the buzz coming back again .
I cant believe it ! There is just a very tiny high treble buzz but it's barely heard or noticeable.. reminds me of the time I had put varnish to quiet it down(super quiet) .
Im only worried and hope the PT legs don't bend over time due to the wood piece acting as an obstacle to tighten the laminations from below in the middle , as this would gradually lead to the buzz coming back again .
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allanmatters
Active Member
The buzz came back surprisingly after almost 5 months . Slowly and steadily and now it's loud just like the last time . I did tighten the screws some time back as it was buzzing . Inspite of that its gradually come back .
So I opened it checked the piece of wood which I had stuffed under the PT. Seems perfectly fine . It's a piece of teak wood . So i dont know if there is any expansion contraction depending on the weather conditions.
Planning to put some araldite two paste glue mixture in the place where the gap is. The gap is where the red circle is on my previous comment with the image .
This is the glue I plan on using
https://www.amazon.in/Araldite-Stan...r-180gms/dp/B00SXUQ0NU?tag=googinhydr18418-21
So I opened it checked the piece of wood which I had stuffed under the PT. Seems perfectly fine . It's a piece of teak wood . So i dont know if there is any expansion contraction depending on the weather conditions.
Planning to put some araldite two paste glue mixture in the place where the gap is. The gap is where the red circle is on my previous comment with the image .
This is the glue I plan on using
https://www.amazon.in/Araldite-Stan...r-180gms/dp/B00SXUQ0NU?tag=googinhydr18418-21
allanmatters
Active Member
DaveVoorhis
Addicted Member
Replace it or live with it. It's probably water/salt damaged and windings are vibrating.
Have you considered replacing the amp?
There are numerous amplifiers that could be obtained inexpensively and would be just as good if not better.
allanmatters
Active Member
I did find a pioneer a-8 . But the seller is charging way too much . 340$.
I don't know why i kill myself so much doing this when what u recommend is completely right .
I need an amp which gives a nice warm sound the a-7 and has a good punch too.
Preferably an amp which is less prone to sickness
How do u find the Nad 7240PE. ?
Some one is offering it for 203$. I read reviews that even though it's just a 40wpc unit , it can give triple its power .
I don't know about warmth of sound etc
I also read that the PE version s of Nad were made with tiawan parts which are not very reliable and that the previous versions of nad had used the Japanese parts inside.
I don't know why i kill myself so much doing this when what u recommend is completely right .
I need an amp which gives a nice warm sound the a-7 and has a good punch too.
Preferably an amp which is less prone to sickness
How do u find the Nad 7240PE. ?
Some one is offering it for 203$. I read reviews that even though it's just a 40wpc unit , it can give triple its power .
I don't know about warmth of sound etc
I also read that the PE version s of Nad were made with tiawan parts which are not very reliable and that the previous versions of nad had used the Japanese parts inside.
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Nightcleaner
Super Member
I have had 2 Musical Fidelity A5's. They seem to come with a statuatory Toredial Transformer Buzz. Not to be confused with a Hum. The reason I have had two is. I past the first one on because of the buzzing. When I listen to say "Flameco Sketches" late at Night "Low Volume" I could hear the buzzing above the music. So I thought it was faulty - passed it on.
Year later or less I saw another for sale plugged it in. Had my Buzz back.
So I Looked into it. Found my answer on an Australian hi fi forum someone else had exactly the same issue.
Remedy: For me anyway: https://www.atlhifi.com/shop/fully-assembled-devices/dc-blocker-trap-filter-assembled-in-case/
Stop the buzzing dead no sound comes out of the case Absoloutly brilliant Brilliant : But Expensive
Year later or less I saw another for sale plugged it in. Had my Buzz back.
So I Looked into it. Found my answer on an Australian hi fi forum someone else had exactly the same issue.
Remedy: For me anyway: https://www.atlhifi.com/shop/fully-assembled-devices/dc-blocker-trap-filter-assembled-in-case/
Stop the buzzing dead no sound comes out of the case Absoloutly brilliant Brilliant : But Expensive
allanmatters
Active Member
Wow . That is something new to me. I appreciate your help on this . But will rather sell it and recover my maintenance cost s .
At least thats the plan. Initially I had found a way to eliminate the buzz by stuffing a piece of wood under the PT and tightening the screws at such an angle ,but it has returned again. In my case it is a faulty power transformer as I have a Pioneer A-9 and that is a torodial based one but silent . Just a default low hum barely noticeable and it's normal .
I still don't mind experimenting . But at the same time I am like this is a waste of my time .
allanmatters
Active Member
There's one more thing I do not mind trying .
Since my amplifier has 110v 120v 220v and 240v as a selector behind . (Currently and it's always been on 240). Will it make a difference if I switch the selector from 240v to 220v ?
I am getting about 235volts . I checked this with a volt meter .
Since my amplifier has 110v 120v 220v and 240v as a selector behind . (Currently and it's always been on 240). Will it make a difference if I switch the selector from 240v to 220v ?
I am getting about 235volts . I checked this with a volt meter .
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DaveVoorhis
Addicted Member
Probably no effect -- other than running the amplifier circuitry on slightly higher voltage than normal -- unless the loose winding(s) that's causing the hum is on the 240v tap.
allanmatters
Active Member
So is it worth a try ?
DaveVoorhis
Addicted Member
It's unlikely to hurt. You will be running the unit internally at slightly higher voltage than before, which might be enough to pop some marginal component.
allanmatters
Active Member
Thank you for the tip. I think i will pass then
allanmatters
Active Member
Hi , I know you are probably going to be tired of my transformer stories .
So fed up with the sound. I submerged the PT in hot varnish . A quarter of it (as I did not want to disconnect the wires from the main power supply board)
I boiled the varnish in a just about right size container and then dipped quarter of the PT in it. Dipped the base first . There were bubbles coming out very slowly one by one .
After the bubbles stopped I then took it out and submerged the other sides of the PT . Did this for all sides . Bubbles were coming very slowly
Then I reheated the varnish again and submerged the other remains sides of the PT. the varnish had become thick by then. But there were still bubbles coming out .
And now I am awaiting results . Will let it dry over night . Give it a day or two
So fed up with the sound. I submerged the PT in hot varnish . A quarter of it (as I did not want to disconnect the wires from the main power supply board)
I boiled the varnish in a just about right size container and then dipped quarter of the PT in it. Dipped the base first . There were bubbles coming out very slowly one by one .
After the bubbles stopped I then took it out and submerged the other sides of the PT . Did this for all sides . Bubbles were coming very slowly
Then I reheated the varnish again and submerged the other remains sides of the PT. the varnish had become thick by then. But there were still bubbles coming out .
And now I am awaiting results . Will let it dry over night . Give it a day or two
allanmatters
Active Member
Significant reduction in buzz about 80% less. I was wondering if any one can help me out on information regarding good main filter caps .
I have options to chose from below
Denon 10000uf 63v
Cornell-dubilier 10000uf 63v
Rubycon 10000uf 63v
I don’t want to shell out money on the Nichicon caps as they don’t fit my budget
I have options to chose from below
Denon 10000uf 63v
Cornell-dubilier 10000uf 63v
Rubycon 10000uf 63v
I don’t want to shell out money on the Nichicon caps as they don’t fit my budget