split load PI gain

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sbirkenstock
Posts: 76
Joined: Fri Oct 17, 2014 10:50 pm

split load PI gain

Post by sbirkenstock »

Hi everybody,

Gerald Weber says in his books, that the split load PI has no gain.
Well, one point to look at it would be, that the gain is split between cathode and plate, since each has a 56K resistor.
So in this view the split load PI should have half the gain of a "regular gain stage" per phase?

Is there actually a way to measure this with a multimeter?

thanks!
Stephan
pdf64
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Joined: Sat Mar 12, 2011 9:23 pm
Location: Staffordshire, UK

Re: split load PI gain

Post by pdf64 »

A cathodyne should have a voltage gain of unity and, at the non-inverting output, a fair bit of current and power gain. Though if the load becomes significant then the balance between the outputs will become affected.
It shouldn't be to much trouble to apply a constant signal input voltage and measure the voltage at the outputs, to verify the unity gain thing.
See http://www.valvewizard.co.uk/cathodyne.html
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Merlinb
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Re: split load PI gain

Post by Merlinb »

sbirkenstock wrote: Is there actually a way to measure this with a multimeter?
Feed in a sine wave of 50 or 60Hz and make sure the amp is not clipping, and you should be able to measure the signal voltages on the AC range of a multimeter. (Provided you measure it at points where there is no DC on the signal, of course, like after a coupling cap).
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