Re: [AMRadio] Any amplifier suggestions?
Hi Todd: Sounds like a fun project. I use a Swan MK2 amplifier on am for 200 w out using two 3-500Zs, input is 30w from an Elmac AF 67. For 2 kvdc I think I would look into a pair of 813's running in grounded grid. The 813 is a very rugged tube and show up at the flea markets and at reasonable prices too. The 572B might be a good choice too but cost more. You said you needed a matching system and also that fewer parts is better. I recommend you avoid build an L tuner. That's the random wire tuner using one capacitor and one coil. I've used them before and they seem to put alot of RF in the shack. I got nipped a bunch of times using a metal D 104 mic. I switched to a T tuner - two caps, one coil and an a balun and the shack rf disappeared. Anyway, have fun! Greg WA7LYO Kinston NC - Original Message - From: "Todd Carpenter" To: Sent: Monday, October 05, 2009 10:29 AM 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/amradio@mailman.qth.net/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Post: AMRadio@mailman.qth.net > To unsubscribe, send an email to amradio-requ...@mailman.qth.net 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/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net 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
Re: [AMRadio] Any amplifier suggestions?
I have a heath dx 60 and vfo to drive it with. Just have to find someone to help me fix the dx60. I am not sure which is better, but no tune would be a plus. I have 6 of the 1625 tubes as well. I also have a 1940 handbook with a single tube 4-400 amp in it. But i am looking for maximum am output. -Original Message- From: John Coleman Sent: Monday, October 05, 2009 10:26 AM To: 'Discussion of AM Radio in the Amateur Service' Subject: Re: [AMRadio] Any amplifier suggestions? 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 __ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net 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
Re: [AMRadio] Any amplifier suggestions?
Hi Todd, A rough rule-of-thumb to help get you started in your choice of tube(s) is the following: your carrier OUTPUT---when the linear amplifier is used as such, i.e. to boost the AM signal driving it from your exciter---is equal to ONE HALF of the plate dissipation of your tubes... I have a pair of G-G 813s in my HB kilowatt: each 813 is good for 125 watts of plate dissipation, so one tube alone would be good for 62.5 watts of carrier output in AM linear mode...the pair of them gives me a total of 125-watts of carrier, with a drive of some modulated 15 watts, or so, at the linear's input jack... No, it may not be "as good" to the purists as a full-bore 200 watt plate carrier modulated by some 100 watts of P-P class B audio, but it'll STILL make your presence on the band known, and in pretty good fashion, too... Besides, have you seen many 100 watt plate modulation transformers for sale anywhere lately...?! ~73~ de Eddy VE3CUI - VE3XZ ** - Original Message - From: "Todd Carpenter" To: Sent: Monday, October 05, 2009 10:29 AM 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/amradio@mailman.qth.net/ > List Rules (must read!): http://w5ami.net/amradiofaq.html > List Home: http://mailman.qth.net/mailman/listinfo/amradio > Post: AMRadio@mailman.qth.net > To unsubscribe, send an email to amradio-requ...@mailman.qth.net 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/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net 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
Re: [AMRadio] Any amplifier suggestions?
Download the manual and schematic for Heathket SP-1000 or Ameritron AL-80. It's a pretty straight forward design running a single 3-500 in grounded grid and good for 160 thru 10M The earlier two 3-500 tube amps that heath sold might work better for AM as the final tubes won't have to work the duty cycle as long. Also check out back copies (pre 1960) of the Handbook for earlier designs. Good luck! Bill-WF1L --- On Mon, 10/5/09, Todd Carpenter wrote: From: Todd Carpenter Subject: [AMRadio] Any amplifier suggestions? To: AMRadio@mailman.qth.net Date: Monday, October 5, 2009, 10:29 AM 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/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net 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/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net 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
Re: [AMRadio] Any amplifier suggestions?
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: amradio-boun...@mailman.qth.net [mailto:amradio-boun...@mailman.qth.net] On Behalf Of Todd Carpenter Sent: Monday, October 05, 2009 9:30 AM To: AMRadio@mailman.qth.net 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/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net 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/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net 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
[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/amradio@mailman.qth.net/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: AMRadio@mailman.qth.net To unsubscribe, send an email to amradio-requ...@mailman.qth.net 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
