Super isolated power transfomer for pre-amp.

[Brian Guralnick]

Hi,

I'm looking for a super isolated power transfomer for pre-amp.
I mean, extra high isolation impedance & isolation voltage & super low leakage current from DC to high frequency.

Who makes the best?

What's usually better, normal, or toroid transformers?

I need 120v primary, 25v+25v secondary at least 15 watts for the analog, a separate second transformer with a secondary at 7v, 5 watt for the digital.

 

[Damon Hill]

So-called 'split bobbin' transformers are widely available that have a pretty high degree of isolation without a Faraday shield.
The primary and secondary windings are physically isolated, unlike a toroid that's usually tightly coupled with primary and
secondaries wound on top of each other. (In output transformers, this is generally A Good Thing.)

This reduces capacitive coupling and thus coupling of line noise onto the secondary. I'd tend to prefer split bobbin transformers
for that reason in most low current applications.

Nevertheless, toroids are 'sexy', and there are good quality devices on the market.

Signal is one manufacturer of many for small pc-mount transformers of split-bobbin design.

http://www.signaltransformer.com/signal/products/products.cfm

 

[jackinnj]

but are there split bobbin xfmrs with enough

permeability to operate at the line frequency? i thought these were mostly used in SMPS.

 

[Brian Guralnick]

So-called 'split bobbin' transformers

Split bobbin was the key term.

I really like the look of their LPI serries.

http://www.signaltransformer.com/signal/products/pdfs/lpi.pdf

Thx a million...