Measuring PT "sag"?

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vanhalen5150
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Measuring PT "sag"?

Post by vanhalen5150 » Thu Oct 18, 2012 7:12 am

Anyone know how the "sag" or power drop is measured on a power transformer?
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Re: Measuring PT "sag"?

Post by chrisom » Thu Oct 18, 2012 2:07 pm

D. Friedman says the sag at the power supply secondary winding is a sag in the current, so you'd have to find a way to measure that. Same issue as measuring mA of current when biasing tubes. Possibly you could measure the voltage & then use ohm's Law to compute the current by plugging in the resistance load value & the voltage value, then doing the math?

Maybe the good old-fashioned osciliscope/dummy load/frequency generator setup would help or be neccesary? Dave? :peace: :) :rockon:

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Re: Measuring PT "sag"?

Post by Roe » Thu Oct 18, 2012 2:44 pm

measure plate voltage at idle and at full distortion. should drop around 90v
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Re: Measuring PT "sag"?

Post by vanhalen5150 » Thu Oct 18, 2012 3:12 pm

So I guess its not so much what the PT does by itself , but more of what the rest of the amp is doing to cause it to.
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Re: Measuring PT "sag"?

Post by Roe » Mon Oct 22, 2012 3:28 am

its about how the PT interacts with the rest yes
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