I have a 6B4G SE amp with DC heaters,and i thought the hum came from the heaters,so I removed all the tubes and dissconnected the separate filaments transformers and switcht the HV transformer on,and the hum is still there!
It´s not much hum but it´s still there.The output trafos are about 3 inches away from the HV transformer,it must come from there.Is there a way to filter this out?🙄
It´s not much hum but it´s still there.The output trafos are about 3 inches away from the HV transformer,it must come from there.Is there a way to filter this out?🙄
Try rotating either of the transformers 90 degrees... or any angle that eliminates the noise.
Also you should have iron-based shields over the windings...
Steel chassis have also been said to create unwanted coupling... although I suspect this is a very minor effect...
😉
Also you should have iron-based shields over the windings...
Steel chassis have also been said to create unwanted coupling... although I suspect this is a very minor effect...
😉
poobah said:
I think that is the problem of the incurable hum in my preamp. I've used a 1mm steel sheet, alluminium is unobtainable here where I live.
I have a 14x14" steel plate and wood frame,and no there is no iron-based shields over the windings...maybee I´ll try to rotate first...😎
You mean to make iron-based shields in aluminum,that I could do,or make a new 14x14" chassie,that I wont do
to muuuch work.😉
to muuuch work.😉
poobah said:
Here at least, absolutely. You can only find in metal surplus places sheets 1mm thick (too little) and 6 meters x 4 meters, and they won't cut it for you, you have to buy the whole sheet (obviously at an insane price).
The best I've found is 1mm steel, 50cm x 25cm, 5 euro each, and with this I've built my preamp.
The windings should have covers made of steel or iron.
An aluminum chassis plate may help. But it may not be the only problem.
Lay one transformer so the laminations are horizontal... the other transformer so the laminations are vertical. That is often best.
Try rotation BEFORE you make a new chassis!
😀
An aluminum chassis plate may help. But it may not be the only problem.
Lay one transformer so the laminations are horizontal... the other transformer so the laminations are vertical. That is often best.
Try rotation BEFORE you make a new chassis!
😀
Well...it´s getting dark here now...😀 😀 😀
Anyone now a good place to order end bells (isn´t that what they are named?).
poobah said:Giaime,
Just a little hint... street signs are made of aluminium...
Already thought about that and already tried 😀 😀 😀
Here at least, they're made from a strange aluminium mix, it's very hard to drill and cut. And I couldn't found a large enought one 😉
ta little hint... street signs are made of aluminium...
Hard to find one /out up here which hasn't been holed from .306 target practise.
richj
Hard to find one /out up here which hasn't been holed from .306 target practise.
richj
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