Posted by 2wo [ 70.110.232.41 ] on August 03, 2006 at 22:10:34:

In Reply to: Re: PS Transformers posted by manualblock on August 03, 2006 at 10:51:54:

Oh No, don’t dismiss the question. The DSR of the transformer you end up with and how that DSR will interact with your filter are very separate questions.

My point is I do not choose a transformer on it’s DSR I find that if I choose a good transformer, low DSR usually happens.

For example, take two transformers from Hammond the 270fx Vs the 370fx. Now the 370 is set up for multiple input voltages but that is beside the point. They are rated very close 139VA for the 270 Vs 142VA for the 370. The 370 is a much beefier transformer and cost twice as much. So what’s up with that? Want to guess witch has the lower DSR?

That aside If you are trying to get close to the "rated" 150ma, which do think will run reasonably cool and not buzz like a… well you get the idea. Now if you only ask for 75-100ma the 270 may work just fine. So were dose that leave us with the DSR?

Your mission should you chose to accept it…Please let us know.;)

As to how to whatever DSR we end up with works into the filter. I need to research as well. First thoughts, model a simple filter. Say 10uf -5mh-50uf to a stepped load. vary the transformer DSR and take good notes. Maybe replace the choke with a resistor. When in doubt use 1k. I think there something on the VT52 site.
What do you say, we work this for a week or so and compare notes?…John

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