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Mesa 7i78
Mesa 7i78
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27 Aug 2021 22:26 #218942
by PCW
What supplies the voltage between SPINDLE+ and SPINDLE- ?
Does the 5V supply droop when loaded?
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28 Aug 2021 16:14 #219017
by PCW
What is the load resistance? The 7I78 should be OK down to ~5K ohm loads
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28 Aug 2021 16:36 #219019
by PCW
OK that cannot work.
What are you driving that has that low of an input impedance?
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28 Aug 2021 17:20 #219029
by PCW
I mean, what does the 7I78 drive? 133 Ohms is a very low impedance for an analog input
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28 Aug 2021 17:22 #219030
by COFHAL
Can't add an electronic circuit that avoids loading the output of that electronic potentiometer?
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28 Aug 2021 17:24 - 28 Aug 2021 17:24 #219031
by PCW
The 7I78 has an op-amp buffer but 133 Ohms is _way_ too low a load resistance
Last edit: 28 Aug 2021 17:24 by
PCW.
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28 Aug 2021 17:24 #219032
by COFHAL
But originally the speed of the spinlde was controlled analogously with a potentiometer.
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Mesa 7i78
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