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## Re: [Amps] tetrode push-pull amp schematics - replacement

 To: "ka4inm@gmail.com" , amps Re: [Amps] tetrode push-pull amp schematics - replacement "Fuqua, Bill L" Sun, 21 Jun 2015 05:53:52 +0000 mailto:amps@contesting.com>
 ``` Classic definition of classes is by conduction angle. A= 360 degrees B=180 degrees AB greater than 180 degrees but less than 360 C= less than 180 degrees subscripts 1= no grid current 2= grid current It is usually assumed that class C amplifiers draw grid current 73 Bill wa4lav ________________________________________ From: Amps [amps-bounces@contesting.com] on behalf of KA4INM [ka4inm@gmail.com] Sent: Saturday, June 20, 2015 9:46 PM To: amps Subject: Re: [Amps] tetrode push-pull amp schematics - replacement On 06/20/2015 06:55 PM, Roger (K8RI) wrote: > Isn't class A idle current max (tube dissipation) with max signal giving > minimum dissipation? (The tube is never driven "into" cut off) Class B > is at cutoff while class C is deep into cutoff? No, with class "A" the idling current is in the center of the most linear portion of the transfer curve.* (roughly half of the maximum (desired) current. The input signal runs the plate current up on one half cycle (+) and down with the other half cycle. (-) The plate dissipation at idle is the same as at full drive. With class "B" the idling current is set at just above cutoff, to eliminate the cross over distortion. Other than at crossover only one tube conducts at a time, each half cycle drives one of the tubes. The plate dissipation increases with drive. Without drive it is very low. With class "C" the idling current is set at or (any amount) below cutoff, frequently increasingly further below cutoff with increases of drive. (grid leak bias) The plate dissipation increases with drive. Without drive it is zero. * I have heard of operating 3-500Z's that idle at about half of the peak plate current and it be called AB1 when it is actually class "A." -- Ron KA4INM - Youvan's corollary: Every action results in unwanted side effects. _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps ```
 Current Thread Re: [Amps] tetrode push-pull amp schematics, (continued) Re: [Amps] tetrode push-pull amp schematics, Gary Smith Re: [Amps] tetrode push-pull amp schematics, Gary Schafer Message not availableRe: [Amps] tetrode push-pull amp schematics, Gary Schafer Re: [Amps] tetrode push-pull amp schematics, KA4INM Re: [Amps] tetrode push-pull amp schematics, Gary Schafer Re: [Amps] tetrode push-pull amp schematics, Peter Voelpel Re: [Amps] tetrode push-pull amp schematics, KA4INM Re: [Amps] tetrode push-pull amp schematics, Roger (K8RI) Re: [Amps] tetrode push-pull amp schematics, KA4INM Re: [Amps] tetrode push-pull amp schematics - replacement, KA4INM Re: [Amps] tetrode push-pull amp schematics - replacement, Fuqua, Bill L <= Message not availableRe: [Amps] tetrode push-pull amp schematics, Gary Schafer Message not available Re: [Amps] tetrode push-pull amp schematics, Hardy Landskov [Amps] tetrode push-pull amp schematics, John Lyles