Toroidal vs EI power amps any difference.

Toroids are prone to mechanical buzzing, vibrating, when fed from AC mains with DC on the Line. Especially large VA Toroids used in power amps. For smaller VA toroids you can buy a plug in DC blocker that will filter out the DC on the mains and in most cases stops the loud mechanical buzzing, vibrating, sound.

Designers like Pass and Bryston install DC blocker filters in their equipment that use Toroid power transformers. Many do not... I see some ARC equipment is now using Toroid power transformers. I imagine ARC is installing DC blocking filters in the equipment.

Unless Krell has changed their design recently they do not install DC blocking filters in their equipment. There are a few threads on Agon about big power Krell Amps that have Toroid power transformers that mechanically buzz, vibrate, quite loudly. The owner tries a plug in DC blocker but it doesn’t stop the loud buzzing.

I believe the problem is the plug in DC blocker is not designed to handle the higher draw of the big VA toroid transformer(s) in the amps.

EI type powers transformers as a rule are not affected by DC on the Line.

DC on the Line:

https://sound-au.com/articles/xfmr-dc.htm

Sorry, the question was sufficiently answered in 2008 post titled “How does OTL amp get its power?” Thanks 

Not exactly on topic, but is there a downside to OTL’s , Futterman, D. Berning?

My current solid state DAC utilizes a toroidal transformer (And it sounds wonderful). I’m currently having a new tube DAC built for me that will have 3 separate toroidal transformers (Also 2 chokes) so a fair amount of iron. Both my tube preamplifier and tube mono blocks utilize “double C-core” transformers and they sound wonderful.

I suspect that like virtually all things concerning audio the major influencing factors are quality of construction and execution. I believe that in the right hands, all of the various types of transformers can contribute to excellent sound quality performance. It is however interesting to explore why different builders chose to use a particular type of transformer.

Charles

@jaytor - exactly.  As a manufacturer we use toroidal as we feel they have less noise.  When I met the Luxman representative about 5 years ago, he told me that Luxman switched to EI as they felt in their tests they performed better.  We have not done a comparison but in our experience we use toroidal in our tube components.

Happy Listening.

Toroidal transformers are quieter to a point, but the larger they get the more susceptible they are to DC offset. I was told it starts to be more common  in toroidal’s over 300va. They can start humming or buzzing because of anything from a space heater to LED lights, especially when they are variable lights.

Toroidal transformers look more techy. They are more expensive to wind. 
 

That’s it. No technical superiority.

https://www.mpaudio.net/post/advantages-toroidal-transformers

The components in my system that sound the best use R-Core transformers.  These use a continuous conductor and have opposing windings to cancel out magnetic flux and have ultra low noise. 

Toroidal transformers are more compact and efficient. They generate less EMI, so are less likely to interfere with other circuits. If well potted, they can also be better mechanically isolated (less chance of buzzing). The biggest downside is they do a much worse job filtering any noise on the incoming AC, so more external circuity is required to do this. 

Good question but you've ignored tube amps were EI reigns dominant.  Toroids are cheaper and lighter.  There are some differences in capacitance and resistance.

OK. that's the limit of my knowledge so now I'll speculate a little.  Transformers are more important in tube amps. (not sure everyone will agree with that).  Transformers for tube amps are more expensive (still, the question is cause or efect, could tube amps be made better with toroids).  

I'm leaning toward the conclusion that EI transformers provide higher quality outputs but SS amps can get by with toroids with filtering.  I will add that toroids are newer and when they were introduced there was a lot of bragging and marketing.  SS amps still often brag about them in their literature, whether is is appropriate or not.

Lastly I am having a custom hgh end amp made.  The transformers are being hand wound in Bulgaria.  They are EI transformers.

I'm eager to see what others have to say on this topic.

Jerry