why toroidal?

[zafira1981]

Hi!!!

what is the diference between normal transformers and toroidal trasnformers? is there any advantage?

I'm asking this because in Argentina i cant find any place to buy a 24+24 toroidal. I can only find 12V toroidals for 12V lamps.

maybe i can use 4x12v toroidal to make 2x24v. is that worth? or just buy an old "EI" transformer?

[Fidelity Audio]

From what I gather a toroidal transformer emitts much less flux which affects the audio.
Plus I think the eddy current is also lower.

[richie00boy]

Smaller magnetic field (leakage), better VA and regulation for same size.

[Tweeker]

EI pluses- lower bandwith, far more tolerance for DC offset. One way to deal with the flux is just have it a couple feet from the amp.

[jcx]

toroidal is really used because they are the cheapest per VA due to more efficient use of materials + investment in auto-winding

EI give better isolation from the line due to lower pri-sec parasitic C, they do have higher leakage flux, but is easily "short circuited" by cheap iron such as tin can stock or even galvanized sheet - some high end manufacturers put EI pwr xfmrs in drawn cylindrical cans to to get superior performance while avoiding questions from those brainwashed by toroidal="hi tech" hype

[AJT]

imho, you miss nothing if you just used EI's...

[davidsrsb]

EIs have lower inrush

Badly made EIs tend to vibrate and buzz audibly

[AJT]

Badly made EIs tend to vibrate and buzz audibly

something that is easily cured!

[zafira1981]

thanks to all!! I only hope that my next EI trans. fit into my case. I will make 4xLM3886 chip amp + 1 dual LM3886(bridged). I dont know how much VA's should be the trans. can you help me?

70W x 4 + 100W = 380W of audio output

500va? 600va?

[richie00boy]

A good rule of thumb is VA = 2 x output RMS