Greetings all. I just joined this group. My background is researching designing toroidal transformers and have extensive knowledge of same. From what I have read so far, there seems to be some misinformation. Pls post any toroid questions and I will do my best to answer them.
Hi Brian,
Great that you joined, Im also fresh here, just a month old member. Thanks for your offer!
There is one thing about toroids thats utterly annoying, a buzz, horrible noise worse than any other. Here people design - 120db noise circuits for power amps, what's worth when toroids just buzzes.
The shop where I was buying my transformers was over sizing the core for about 20% of nominal power, then vacuum lacquer it and then double bake it. Result is much better but sometimes it still does very quiet, but horrible buzzz.
Can we get rid of it all together? Make completely silent trafo in 300 to 1000w range, is that feasible?
Great that you joined, Im also fresh here, just a month old member. Thanks for your offer!
There is one thing about toroids thats utterly annoying, a buzz, horrible noise worse than any other. Here people design - 120db noise circuits for power amps, what's worth when toroids just buzzes.
The shop where I was buying my transformers was over sizing the core for about 20% of nominal power, then vacuum lacquer it and then double bake it. Result is much better but sometimes it still does very quiet, but horrible buzzz.
Can we get rid of it all together? Make completely silent trafo in 300 to 1000w range, is that feasible?
Hello Brian,
Please take a look at this thread:https://www.diyaudio.com/community/threads/no-electrostatic-screen-on-toroid.408993/#post-7596055
Please take a look at this thread:https://www.diyaudio.com/community/threads/no-electrostatic-screen-on-toroid.408993/#post-7596055
Hi Brian
Thanks for your offer. I'm interested in your view on potential issues that might arise when using a toroidal power transformer with a split primary winding (120-0-120v) as a pushpull output transformer using, in my case, an 8v secondary to give around 7k2 ohms pp with an 8ohm sec load. Possibly a similar query to post #3.
Thanks for your offer. I'm interested in your view on potential issues that might arise when using a toroidal power transformer with a split primary winding (120-0-120v) as a pushpull output transformer using, in my case, an 8v secondary to give around 7k2 ohms pp with an 8ohm sec load. Possibly a similar query to post #3.
I am curious what you have there. I am attaching the PDFs of two isolation transformers I have been considering for tube amps.
One is EI (2.5kgs), the other toroidal (1.6kgs), with similar VA ratings. The EI has a regulation of 25%, the toroidal 8%, so the output resistance of the toroidal is clearly lower than that of the EI?
https://eu.mouser.com/datasheet/2/410/VPS230_760-781512.pdf
https://eu.mouser.com/datasheet/2/410/VPS230_760-781512.pdf
I'm not the missing expert, but may help a little.
If your transformer is sometimes silent and sometimes makes noise (buzz, hum), this is your mains having a DC component. This is a common problem. Sometimes you can even notice the noise getting louder and disapear, periodical or very randomly. This is because not only nice loads use the electicity net. Some say, since inducing solar made electricity is injected into the net it got worse. There may be quite some noise during the day, but solar is down at night, while random glitches continue.
Audiophiles have build the most expensive toroids you can think of, but with no effect. Anly solution is to live with it (simply turn on some music, it helps!) or put the transformer in a well isolated box. Even putting it on some soft, absorbend material will reduce noise a great deal. Most anoying are resonating cases. You got to do some thinking to keep the transformer floating, but still hold it in place when you move your gear. Usuall no real problem for a smart engineer, as you only need a very small gap to isolate from the housing.
If you do not run permanent high levels like in a live concert, heat with the usual overdimensioned toroid for HIFI should be no problem, even in a closed metal case, hidden in a cabinet.
Anyway, please don't wrap your whole transformer in any foam or whatever. You don't want to isolate it for heat, but for noise! At least the radius should be exposed to free air. Top and bottom can rest on some elastic material, like neopren. If unsure, check temperatures after a few hours.
You can even heat fuse it.
If you want to get 100% rid of noise, you can use a quite simple diode-capacitor DC blocker. Some say it is taking away sound quality, but this is more a mental problem than technical. Some high end amps have such a device build in.
If your transformer is sometimes silent and sometimes makes noise (buzz, hum), this is your mains having a DC component. This is a common problem. Sometimes you can even notice the noise getting louder and disapear, periodical or very randomly. This is because not only nice loads use the electicity net. Some say, since inducing solar made electricity is injected into the net it got worse. There may be quite some noise during the day, but solar is down at night, while random glitches continue.
Audiophiles have build the most expensive toroids you can think of, but with no effect. Anly solution is to live with it (simply turn on some music, it helps!) or put the transformer in a well isolated box. Even putting it on some soft, absorbend material will reduce noise a great deal. Most anoying are resonating cases. You got to do some thinking to keep the transformer floating, but still hold it in place when you move your gear. Usuall no real problem for a smart engineer, as you only need a very small gap to isolate from the housing.
If you do not run permanent high levels like in a live concert, heat with the usual overdimensioned toroid for HIFI should be no problem, even in a closed metal case, hidden in a cabinet.
Anyway, please don't wrap your whole transformer in any foam or whatever. You don't want to isolate it for heat, but for noise! At least the radius should be exposed to free air. Top and bottom can rest on some elastic material, like neopren. If unsure, check temperatures after a few hours.
You can even heat fuse it.
If you want to get 100% rid of noise, you can use a quite simple diode-capacitor DC blocker. Some say it is taking away sound quality, but this is more a mental problem than technical. Some high end amps have such a device build in.
Buzzing toroids? Possible only with low quality ones, never mind if manufacturer claims great quality, or with high DC at mains.
I’ve bought, so far, 6 audio grade toroidal transformers from toroidy.pl and have never heard even the slightest sound form them.
https://sklep.toroidy.pl/en_US/c/Toroidal-transformers-AUDIO-GRADE/75
I’ve bought, so far, 6 audio grade toroidal transformers from toroidy.pl and have never heard even the slightest sound form them.
https://sklep.toroidy.pl/en_US/c/Toroidal-transformers-AUDIO-GRADE/75
Hello people,
Thanks for reaction!
I was ordering my trafos with 20% oversized core, vacuum varnished several times (once for core, for primary and then for secondary).. This reduces buzz to minimum, but it's still there. Nevertheless it's much better than all commercial audio trafos I have bought.
This is OCD issue, with slightest music it's not hear able, but hate the buzz....
I tried DC blocker at mains input, no difference where I live.
I also sealed many trafos in epoxy,and this is very liquid epoxy with 24 hrs settling time, this penetrates deep, first I removed outside wrapping. This also helps, but still it's not zero buzz. Here are examples
Then we have commercial Amp Trafos, mostly EI core welded on corners, and the buzz is even lover than with crazy effort I put in toroids, what's the catch?
Thanks for reaction!
I was ordering my trafos with 20% oversized core, vacuum varnished several times (once for core, for primary and then for secondary).. This reduces buzz to minimum, but it's still there. Nevertheless it's much better than all commercial audio trafos I have bought.
This is OCD issue, with slightest music it's not hear able, but hate the buzz....
I tried DC blocker at mains input, no difference where I live.
I also sealed many trafos in epoxy,and this is very liquid epoxy with 24 hrs settling time, this penetrates deep, first I removed outside wrapping. This also helps, but still it's not zero buzz. Here are examples
Then we have commercial Amp Trafos, mostly EI core welded on corners, and the buzz is even lover than with crazy effort I put in toroids, what's the catch?
NOT, absolutely not, but we have LC filters to cure that.
My issue and question is the noise from transformer itself, not electrical noise passed through it, or electromagnetic al induction..
How to stop transformer making noise all together, without Amp attached to it?
And here problem is only with 200VA + pieces.