isolation transformer vs line conditioner

Wow, never saw this response from 7b4me and it's a year later.

I didn't read the material that you mentioned on Bryston's website, so forgive me for my ignorance as to their point of view. As far as my comments being wrong, i think that you'll find that most EE's that are both honest and well educated will agree with my comments. Aball's response above the multitude of comments that John Curl has made on the subject are prime examples.

Toriodal transformers only have one real electrical advantage over EI's when used as a power transformer. That is, toroids reduce stray electromagnetic radiation as compared to EI's. They can be placed closer to circuitry with less potential for interference. By placing end caps or "bells" on the EI's, radiation can be reduced to near that of a toroid by itself, but once again, this raises cost and weight. To be fair, applying the same amount of metal to a toroid as a shield lowers the stray radiation to the point that an EI could never come close.

Outside of power transformers, toroids are far superior to EI's for use as impedance matching transformers. This has to do with their capacity to cover a larger cross-section of frequencies i.e. wider bandwidth. For audio signals, this is a highly desirable trait. For a power transformer, it is exactly what we don't want.

In this respect, it all boils down using the right tools / circuitry. Whether or not one wants to get the job done or to design / build something that performs optimally are two different things. Sean
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LOL,

Wow Sean, you got called out here! If only 7b4me knew who he was trying to show up with one manufacturers sales propaganda. Mighty funny. I'm glad you caught this Sean, and I'm happy the thread is back, I forgot about this one.

Have a great Holiday Sean,

jd

I have a Runnings Springs Audio power conditioner that I have been very pleased with, but I have been very curious about iso transformers for my digital transport and DAC. I just bought a Topaz 500VA ultra isolation transformer and plan to use it for my transport an d DAC. Can anyone tell me the importance of capcitance in the iso transformer. This is something I'm still curious about.

JD: People can believe whatever and whomever they want to believe. All we can do here is share opinions and ideas while trying to learn from one another.

Having said that, most of the Bryston amps are not real strong performers into lower impedances. We have discussed this in the forums here before on more than one occassion.

As most know, these are SS amps with low output impedances and relatively robust output stages. As such, the only reason that this could be so would be due to the limited current capacity of the power supply. Since the power supply starts at the transformer, one should be able to draw logical conclusions as to what is going on here.

Clio09: The higher the capacitance of a power transformer, the more coupling there is between the primary side of the transformer and that of the secondary. As such, the greater the capacitance, the less isolation the transformer can offer. In such a case, a higher percentage of line noise is allowed to enter into the circuitry with a higher capacitance transformer as compared to a lower capacitance transformer.

As a general rule, toroids are typically much higher in capacitance than a well designed EI. This makes them less suitable for isolation purposes, as i previously stated. On the other hand, EI transformers are typically more lossy as frequency climbs, making them less suitable for wide bandwidth circuits. As such, a well designed tubed amp might make use of an EI in the power supply and toroidals as output transformers. This should achieve the best of both worlds i.e. lower noise floor with wider bandwidth / better transient response. Sean
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sean,

what would you consider a high capacitance for a 1kva toroid?

your comments, as always, are interesting: i found that my old wavac SET, which employed EI-type trannys, was guilty of the rolled off frequency extremes, but glorious at the mids. my SS amps are far more linear, but never as "pure" in the mids or the highs.

rhyno