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ampage archive
Vintage threads from the first ten years
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Re: Scott Heaters for PA Cathode Resistors
 4/23/2000 12:30 AM |
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Ken Gilbert | Re: Scott Heaters for PA Cathode Resistors ray, something else to keep in mind... if the amp is biased colder than class a, you will obviously have a higher average plate current as you start cranking it up. this will raise the voltage at the cathodes thereby increasing your heater power dissipated. just make sure you monitor that effect on the bench and see how bad it is. don't worry about elevating the dc heaters. if they're good and quiet (which the cathode current would be) then they'll be silent as death regardless of where they're referenced. today i added a mosfet regulator to the B+ in the preamp and it did make a difference. i like it--it IS quieter and no longer dependent on line voltage. i did blow out an irf840 because i didn't have the gate protection zener in place. luckily i had a couple. source impedance is around 0.1 ohm. kg |
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| Ray Ivers Ken, |