Todd, Typically the linear amp will be the fewer parts and expense but with less output than a full plate modulated class C rig per a given tube. One of the simplest tetrode linear systems is to put a 50 ohm load resistor right on the grid of a big jug like a 4-1000 or a pair of 4-400s and use a zener to bias the cathode circuit or fil return. It will also require a screen supply. The idea in all of this is that if the grid is loaded with a 50 ohm dummy load, then it will not require tuning. The small amount of input capacitance will be negligible on the lower freq bands. And it should not require neutralization.
OTH, If you are going linear with a triode or triode connected tetrodes then you will want to go to a grounded grid linear. No screen supply, no neutralization, but does require more drive and/or may require drive tuning. You may expect very poor plate efficiency in any linier amp that is tuned properly to work with an AM input. If you're looking for old style circuits that are proven to have the most output with the least plate dissipation (smallest tubes) then plate modulated full class C finals with push pull class B modulators is best. More work more parts, but well worth the time and effort in the long run. My favorite in small legal limit stuff would be a pair of 812s push pull class C, modulated by a pair of 811a is class B. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Todd Carpenter Sent: Monday, October 05, 2009 9:30 AM To: [email protected] Subject: [AMRadio] Any amplifier suggestions? I am interested is a simple design hf amplifier for am cw on 160-80/75-40. These are the bands i operate on where the extra power would help. Fewer parts count the better. Ultimately lower cost the better. I have power supply parts and believe that i can generate around 2000 volts. I am slowly researching tubes and am leaning toward 2 or 4 tubes that can basically generate lots of watts at half to two thirds their ratings to prolong their life span. Perhaps tubes such as 811's, 810's, 833's, 4-400's. I am open to suggestions. I will need to build or acquire a heavy duty matching system as part of the amp. My goal is at least 300 Watts AM. I do not want to mess with systems that require cooling other than fans. I am not interested in modes for this amp other than am and cw. It will almost exclusively be used for am as i rarely use more than 5 watts on cw any way. Simpler cheaper is better for me. I appreciate your suggestions. Todd ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/[email protected]/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: [email protected] To unsubscribe, send an email to [email protected] with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/[email protected]/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: [email protected] To unsubscribe, send an email to [email protected] with the word unsubscribe in the message body. This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
