Re: [AMRadio] info wanted on 4-400 linear amplifier
Ait was finished. The tube lasted quite well and I still have it here as a test tube for the T-368s I end up working on. snip will you guys stop talking about T-368's that and the BC 610 were all i dreamed about when i was younger . ran a Globe Champion 350A for years then that silly slop bucket stuff came along and i got dx nuts. now 40 years later i have obtained another 350A. just have to get the tranny rewound and it should be good to go.. but it is not the T or BC that i still dream of.. hummm anyone trade a good working T 368 for a few rice boxes ? hi hi.. 73 Tony wa4jqs Since 1962
Re: [AMRadio] info wanted on 4-400 linear amplifier
yep, that is the one, ran AM CW and RTTY with it for over five years after it was finished. The tube lasted quite well and I still have it here as a test tube for the T-368s I end up working on. The circuit lends itself to using the 4-250 as well the neutralizing will need to be adjusted however. Great rig. Jim WB2FCN P.S. I still have the control deck somewhere in all this stuff! :-)
Re: [AMRadio] info wanted on 4-400 linear amplifier
PJ You are correct. i used one for years and never had any problems . I did later put 3b28's in place of the 866a's and added 12 more mf to the supply if i recall. I now have another one that i got in working order. just need to recap one of my two low power BA's to use with it. or build a swamping pad for the Globe 680A. 73 Tony At 08:48 PM 8/3/2005 -0500, you wrote: The Thunderbolt was easily driven to full input by 20 watts. I recall it was easy to tune and very sensitive due to grid drive. The grid was swamped as I recall, so it was also very stable. PJ -- the Johnson Thunderbolt is a AB2 amp that uses 4-400A's check out this amp i think you might like the layout it uses a roller inductor instead of a varicap. 73 Tony wa4jqs __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net Anthony W. DePrato WA4JQS EXTRA - HEAVY CLASS Since 1962 South Sandwich Island Antarctic Dxpedition Group VP8BZL VP8SSI 3Y0PI V31SS ZD8JQS WA4JQS/4K1 WA4JQS/KC4 WA4JQS/ZS1 CQ DX HALL OF FAME # 35 A1-OP FISTS # 10573 AMI
Re: [AMRadio] info wanted on 4-400 linear amplifier
In a message dated 8/3/05 8:08:07 PM, [EMAIL PROTECTED] writes: > The 1962 ARRL handbook has a single 4-400A amplifier, which I think is > the original question > Grid driven circuit, dual mode, AB1 and class C. Dennis D. W7QHO Glendale, CA
Re: [AMRadio] info wanted on 4-400 linear amplifier
Ah, Actually, it was 20 - 30 RF volts. Grid drive is around 5 MA. I use mine with a Pacemaker driver, and a 20 DB ~ pad inline and the connecting coax is prescribed to be 60 inches long to prevent parasitics. The thunderbolt can also be driven directly by an (un)modified Central Electronics 20A, or the CE 10B, I use both of them from time to time. In SSB mode, you really need to watch the audio levels and monitor the RF output waveform, however I found that when running AM from the CE rigs you really have to be careful not to bang the audio as well as the T-Bolt goes right along and you end up with a higher carrier level and lower read (muddled) audio. The 1962 ARRL handbook has a single 4-400A amplifier, which I think is the original question, I built one in the 1980s I had no problems with it, and I redesigned the output to use vacuum variables and a roller inductor instead of all the thrashing around with jumpers. It worked quite well, and I still had to reduced the drive level to keep it in limits for the tube. With 3KV on the plate it is quite handy for rtty and cw, the AM was handled by lifting the modulator circuit from a t-368 schematic, worked quite well. Jim WB2FCN Patrick Jankowiak wrote: > > The Thunderbolt was easily driven to full input by 20 watts. I > recall it was easy to tune and very sensitive due to grid drive. > The grid was swamped as I recall, so it was also very stable. > > PJ > -- > > the Johnson Thunderbolt is a AB2 amp that uses 4-400A's check > out this amp > i think you might like the layout it uses a roller inductor > instead of a > varicap. > 73 Tony wa4jqs > __ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] info wanted on 4-400 linear amplifier
The Thunderbolt was easily driven to full input by 20 watts. I recall it was easy to tune and very sensitive due to grid drive. The grid was swamped as I recall, so it was also very stable. PJ -- the Johnson Thunderbolt is a AB2 amp that uses 4-400A's check out this amp i think you might like the layout it uses a roller inductor instead of a varicap. 73 Tony wa4jqs
Re: [AMRadio] info wanted on 4-400 linear amplifier
Thanks, Tony. Ed K6UUZ On Tue, 02 Aug 2005 23:06:07 -0400 "Anthony W. DePrato" <[EMAIL PROTECTED]> writes: > Ed: > the Johnson Thunderbolt is a AB2 amp that uses 4-400A's check out > this amp > i think you might like the layout it uses a roller inductor instead > of a > varicap. > 73 Tony wa4jqs > > At 06:10 PM 8/2/2005 -0700, you wrote: > >I am planning to build a linear amp around a grid driven 4-400 > tube. Can > >anyone suggest where I can find a suitable circuit with component > values. > >I would like band-switching for 80, 40 and 20 meters. I will be > driving > >it with a 25 watt carrier output rice box on AM. I don't like the > one in > >the ARRL 1967 handbook because it requires you to open the lid and > >physically change taps on the coil and change tuning capacitors. I > don't > >have any other older handbooks. Thank you. > > > >Ed K6UUZ > >__ > >AMRadio mailing list > >Home: http://mailman.qth.net/mailman/listinfo/amradio > >Help: http://mailman.qth.net/mmfaq.html > >Post: mailto:AMRadio@mailman.qth.net > > Anthony W. DePrato WA4JQS > EXTRA - HEAVY CLASS > Since 1962 > South Sandwich Island Antarctic Dxpedition Group > VP8BZL VP8SSI 3Y0PI V31SS ZD8JQS WA4JQS/4K1 WA4JQS/KC4 WA4JQS/ZS1 > CQ DX HALL OF FAME # 35 > A1-OP FISTS # 10573 AMI > > __ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > >
Re: [AMRadio] info wanted on 4-400 linear amplifier
Thanks, Jim. Ed K6UUZ On Tue, 2 Aug 2005 20:07:29 -0700 (PDT) Jim Candela <[EMAIL PROTECTED]> writes: > > Ed, > > I always admire those about to undertake such a > project. I don't have a circuit for you, but I will > share a few ideas. If you do use grid driven, it will > likely need to be class AB1 (zero drive power to tube, > i.e, just voltage), or class Ab2 where the grid draws > a little grid current on modulation peaks. In either > case, 25 watts will be way too much. Given the above > choices, I'd use Ab1, and a passive 50 ohm grid input > resistor, and scale the drive just short of grid > current. Still you will need a grid bias supply, and > screen supply in addition to a plate supply. That is a > lot of stuff, but hey, why not if you want to do it? > > Another approach, and I'm being a little simplistic > here, is to think of a 4-400 in grounded grid as > something similar to or about 4/5 a 3-500Z. A Heath > SB-220 does legal limit AM with under 25 watts > (carrier) of drive with two 3-500Z's in parallel G-G. > No screen supply needed, and bias if necessary is easy > with a power zener diode. So a 4-400 configured as a > GG linear should be good for 150 to 200 watts am > carrier output, and only need 10-15 watts carrier for > drive. My figures are a SWAG, but I'd bet they are in > the ballpark. > > Thanks for reading, > Jim Candela > WD5JKO > --- [EMAIL PROTECTED] wrote: > > > I am planning to build a linear amp around a grid > > driven 4-400 tube. Can > > anyone suggest where I can find a suitable circuit > > with component values. > > I would like band-switching for 80, 40 and 20 > > meters. I will be driving > > it with a 25 watt carrier output rice box on AM. I > > don't like the one in > > the ARRL 1967 handbook because it requires you to > > open the lid and > > physically change taps on the coil and change tuning > > capacitors. I don't > > have any other older handbooks. Thank you. > > > > Ed K6UUZ > > > > > AMRadio mailing list > > Home: > > http://mailman.qth.net/mailman/listinfo/amradio > > Help: http://mailman.qth.net/mmfaq.html > > Post: mailto:AMRadio@mailman.qth.net > > > > __ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > >
RE: [AMRadio] info wanted on 4-400 linear amplifier
Sorry about the spelling! You may want to join in the mail group called AMPS CONTESTING lots of really smart guys their on linear amps. -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of John Coleman ARS WA5BXO Sent: Wednesday, August 03, 2005 9:09 AM To: 'Discussion of AM Radio' Subject: RE: [AMRadio] info wanted on 4-400 linear amplifier Grid driven linear amps are a challenge sometimes even tetrode tubes need to be neutralized. Neutralization not only prevents spurious oscillations but it also stops phase modulation products. Swamping the grid circuit with a dummy load is a good idea because it reduces the 90 degree feedback that we are trying to neutralize and makes the driver radio a lot happier with a more constant load. The nice thing about grid driven is it would be easy later on to plate modulate and run it class C. As for linear amps I thing GG is a better solution especially with triode tubes made for the purpose. You may want to join in the mail group called AMPS CONSTESTING lots of really smart guys their on linear amps. John WA5BXO -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, August 02, 2005 8:10 PM To: amradio@mailman.qth.net Subject: [AMRadio] info wanted on 4-400 linear amplifier I am planning to build a linear amp around a grid driven 4-400 tube. Can anyone suggest where I can find a suitable circuit with component values. I would like band-switching for 80, 40 and 20 meters. I will be driving it with a 25 watt carrier output rice box on AM. I don't like the one in the ARRL 1967 handbook because it requires you to open the lid and physically change taps on the coil and change tuning capacitors. I don't have any other older handbooks. Thank you. Ed K6UUZ __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
RE: [AMRadio] info wanted on 4-400 linear amplifier
Grid driven linear amps are a challenge sometimes even tetrode tubes need to be neutralized. Neutralization not only prevents spurious oscillations but it also stops phase modulation products. Swamping the grid circuit with a dummy load is a good idea because it reduces the 90 degree feedback that we are trying to neutralize and makes the driver radio a lot happier with a more constant load. The nice thing about grid driven is it would be easy later on to plate modulate and run it class C. As for linear amps I thing GG is a better solution especially with triode tubes made for the purpose. You may want to join in the mail group called AMPS CONSTESTING lots of really smart guys their on linear amps. John WA5BXO -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, August 02, 2005 8:10 PM To: amradio@mailman.qth.net Subject: [AMRadio] info wanted on 4-400 linear amplifier I am planning to build a linear amp around a grid driven 4-400 tube. Can anyone suggest where I can find a suitable circuit with component values. I would like band-switching for 80, 40 and 20 meters. I will be driving it with a 25 watt carrier output rice box on AM. I don't like the one in the ARRL 1967 handbook because it requires you to open the lid and physically change taps on the coil and change tuning capacitors. I don't have any other older handbooks. Thank you. Ed K6UUZ __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net
Re: [AMRadio] info wanted on 4-400 linear amplifier
Ed, I would go for a grounded grid circuit. As Jim pointed out, 25 watts too much for grid driven AB1 or AB2. Don't have an exact circuit, but the1983 Handbook describes an amp using a pair of 4-400s running GG. Am sure it could be adapted to a single tube, or maybe you'd consider running a pair. I can copy the article for you. Dennis D. W7QHO Glendale, CA
Re: [AMRadio] info wanted on 4-400 linear amplifier
Ed, I always admire those about to undertake such a project. I don't have a circuit for you, but I will share a few ideas. If you do use grid driven, it will likely need to be class AB1 (zero drive power to tube, i.e, just voltage), or class Ab2 where the grid draws a little grid current on modulation peaks. In either case, 25 watts will be way too much. Given the above choices, I'd use Ab1, and a passive 50 ohm grid input resistor, and scale the drive just short of grid current. Still you will need a grid bias supply, and screen supply in addition to a plate supply. That is a lot of stuff, but hey, why not if you want to do it? Another approach, and I'm being a little simplistic here, is to think of a 4-400 in grounded grid as something similar to or about 4/5 a 3-500Z. A Heath SB-220 does legal limit AM with under 25 watts (carrier) of drive with two 3-500Z's in parallel G-G. No screen supply needed, and bias if necessary is easy with a power zener diode. So a 4-400 configured as a GG linear should be good for 150 to 200 watts am carrier output, and only need 10-15 watts carrier for drive. My figures are a SWAG, but I'd bet they are in the ballpark. Thanks for reading, Jim Candela WD5JKO --- [EMAIL PROTECTED] wrote: > I am planning to build a linear amp around a grid > driven 4-400 tube. Can > anyone suggest where I can find a suitable circuit > with component values. > I would like band-switching for 80, 40 and 20 > meters. I will be driving > it with a 25 watt carrier output rice box on AM. I > don't like the one in > the ARRL 1967 handbook because it requires you to > open the lid and > physically change taps on the coil and change tuning > capacitors. I don't > have any other older handbooks. Thank you. > > Ed K6UUZ > __ > AMRadio mailing list > Home: > http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net >
Re: [AMRadio] info wanted on 4-400 linear amplifier
Ed: the Johnson Thunderbolt is a AB2 amp that uses 4-400A's check out this amp i think you might like the layout it uses a roller inductor instead of a varicap. 73 Tony wa4jqs At 06:10 PM 8/2/2005 -0700, you wrote: I am planning to build a linear amp around a grid driven 4-400 tube. Can anyone suggest where I can find a suitable circuit with component values. I would like band-switching for 80, 40 and 20 meters. I will be driving it with a 25 watt carrier output rice box on AM. I don't like the one in the ARRL 1967 handbook because it requires you to open the lid and physically change taps on the coil and change tuning capacitors. I don't have any other older handbooks. Thank you. Ed K6UUZ __ AMRadio mailing list Home: http://mailman.qth.net/mailman/listinfo/amradio Help: http://mailman.qth.net/mmfaq.html Post: mailto:AMRadio@mailman.qth.net Anthony W. DePrato WA4JQS EXTRA - HEAVY CLASS Since 1962 South Sandwich Island Antarctic Dxpedition Group VP8BZL VP8SSI 3Y0PI V31SS ZD8JQS WA4JQS/4K1 WA4JQS/KC4 WA4JQS/ZS1 CQ DX HALL OF FAME # 35 A1-OP FISTS # 10573 AMI
[AMRadio] info wanted on 4-400 linear amplifier
I am planning to build a linear amp around a grid driven 4-400 tube. Can anyone suggest where I can find a suitable circuit with component values. I would like band-switching for 80, 40 and 20 meters. I will be driving it with a 25 watt carrier output rice box on AM. I don't like the one in the ARRL 1967 handbook because it requires you to open the lid and physically change taps on the coil and change tuning capacitors. I don't have any other older handbooks. Thank you. Ed K6UUZ
