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Hoffman Amps Forum image Author Topic: cathode resistor  (Read 1757 times)

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Offline EKDENTON

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cathode resistor
« on: April 15, 2016, 12:07:21 pm »
On the schematic below it has the cathodes on V2 tied together. This would create twice the current on the cathode....right?  Should that 1k2 be changed to a 750 ohm resistor?  The capacitor symbols seem to be drawn odd also.....
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Offline HotBluePlates

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Re: cathode resistor
« Reply #1 on: April 15, 2016, 12:20:53 pm »
On the schematic below it has the cathodes on V2 tied together. This would create twice the current on the cathode....right?  Should that 1k2 be changed to a 750 ohm resistor?  ...

Did you mean 1.5kΩ? The only 1.2kΩ resistor I see is in the long-tail inverter.

If you mean one of the 1.5kΩ resistors, they shouldn't share a cathode connection because they're amplifying opposite-phase signals. The cathode connection would be positive feedback...

...  The capacitor symbols seem to be drawn odd also.....

Whoever drew the schematic used a symbol for a polarized cap everywhere, likely without understanding what it implied. They also drew the curved plate (usually the - plate) on the wrong side for all the e'lytic caps. Oh well...

Offline EKDENTON

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Re: cathode resistor
« Reply #2 on: April 15, 2016, 01:57:28 pm »
opps! I was looking at the wrong schemtic. That is the phase inverter not the second valve. Sorry, I should have looked at that closer before asking that.
You only fail ... if you quit trying.

 


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