Otherwise, watch for six eimac 3500zs, a couple of peter dahl transformers, capacitor boards, roller inductors, etc. The hammond hla hf linear amplifier is a onestage linear amplifier using one glass envelope 3 500z eimac triode. Operation with zero grid bias simplifies associated circuitry by eliminating the bias supply. Cabinet of power supply should be grounded to amplifier cabinet as safety measure. When a single 3 500z is driven by 100w, it flattops and produces distortion. Download umdgen umdgen enables users to view and edit iso files for the. Jai cette lampe 3500z sur une etagere depuis des annees. The maximuminput rating of the eimac 3 500z, for radio frequency power amplifier or oscillator service is 110mhz.
The keydown current with a 3500z was 420 ma and standing current of 70 ma, resulting in a rf output of 430 w. When a single 3500z is driven by 100w, it flattops and produces distortion. The qb3300 tubes and sockets are available from malcolm mcintosh, 26 branch creek rd, clear mountain, qld 4500. Nos eimac 3500z shows up about once a month, taylor 3500zg has an instant supply of tubes, of course. The main category is amateur linear amplifiers that is about hf amplifiers for ham radio use. From brochure the by eimac typical cathode driven grounded grid amplifier circuit for two 3 500z tubes.
A 25 ohm lowl cathode feedback resistor will make a 3500z linear with 100w of drive. Kenwood tl922 linear amplifier 2 x 3500z eimac valves. The elmac 3500z is a compact power triode intended to be used as a zerobias class ab 2 amplifier in audio or radiofrequency applications. About 3500z amplifier project the resource is currently listed in in a single category. The taylor are stated to have a 600 watt plate vs the eimac 500 watt plate, but needs extra cooling. Download umdgen the umd file creator for psp games via downzen, just. Pictures of the 3500z homebrew linear amp eimac 3500z tubes and chimneys. Click here to read the datasheet of the eimac 3500z tube.
In addition, groundedgrid operation is attractive since a feedback. The amplifier features fast warm up and 1500watt rf output with 100watts of drive. A onekilowatt amplifier using a 3 500z 183 ml rfci capacitor bank r5 ui fan top view. Fox tango yaesu amplifier page, improved anode circuit. Higher zsac for a given ep and close to 10% more output for a given value of drive. A onekilowatt amplifier using a 3500z 183 ml rfci capacitor bank r5 ui fan top view. A twokilowatt amplifier using the eimac 8877 triode one 8877 or 3cx1500 arrl handbook 1978, pp. Al80b instruction manual 1 features the al80b uses a rugged, inexpensive 3500z tube.
The keydown current with a 3500z was 420 ma and standing current of 70 ma. Highquality power supply and rf components combine with an accurate peakdetecting directional coupler, front panel adjustable true alc circuit, and automatic bias switching to make this the best featured and most reliable single 3 500z amplifier available. This amplifier only has a tuned input circuit for the 20 meter amateur band in this video. The authors discuss the development of a tube tester for high power transmitting tubes and modified amplifiers that used the 3500z and 3cx1500 8877 tubes. It was designed and constructed by william moneysmith, w4nfr. The 3500z requires only a few seconds of warmup time. Homemade amp with six eimac 3500zs what do i do with it.
In all cases, air flow rates in excess of the minimum requirements will prolong tube life. This link is listed in our web site directory since saturday oct 5 20, and till today 3500z amplifier project has been followed for a total of 907 times. The types of problems needed to test for are described, including open. Nos eimac 3 500z shows up about once a month, taylor 3 500zg has an instant supply of tubes, of course. A dynamic bias circuit eliminates hundreds of watts of unnecessary heat generation in the power amplifier tube. A 25 ohm lowl cathode feedback resistor will make a 3 500z linear with 100w of drive. The 3500z is a relatively inexpensive tube and has been around for a long time. The al80b uses a single 3 500z tube in a class ab2 grounded grid circuit. It is designed with good quality components and there are separate transformers for the hv and filaments. Pictures of the 3500z homebrew linear amp eimac 3500z tubes and chimneys air blower grey manifold behind tuning board forces air under the chassis through a formed cavity to make the air come up around the base of the 3500z and through the chimneys. This series of socket also fits the 4250, 4400 and 3500z transmitting tubes. The 3 500z is a relatively inexpensive tube and has been around for a long time. With reference to the original schematic from the heathkit sb.
This series of socket also fits the 4250, 4400 and 3 500z transmitting tubes. Amplifiertotransceiver alc works properly only on constant signal level modes such as rtty and fm. The following describes a 16010 meter linear amplifier that uses a pair of 3 500z triode power tubes. Eimac 3400z grounded grid linear amplifier build for amateur. Antique electronic supply chelmer valve company d and c electronics eimac. The need for radio ham operators who use a vacuum tube power amplifier to test new or used spare tubes is addressed. And all this from a guy who keeps having intermittent audio, beats on the rig and it moves up the band about 3kc every smash and meanwhile merrily and blissfully in locked mike mode yapping away as he is heading into slopbucket land. My 6m station consists of an all mode transceiver, usually the elecraft k3, a my dualband 6m4m beam and a home made 3 500z linear amplifier, producing a clean 400w of rf, or a solid state 300w pa producing somewhat less clean signals. Circuit design for highpower linear amplifiers actuated. In addition, groundedgrid operation is attractive since power gain as high as twenty times can be obtained. In addition, groundedgrid operation is attractive since power gain as high as twenty times can be obtained with the 3500z. In keeping with the past tradition of the hl500 and hl750 series amplifiers, only the highest quality components were used in the design of this. Jim gave me the manila folder full of designs, schematics and information on linear amplifiers and i will absorb as much as i can from it.
Discussion in amateur radio amplifiers started by k7joe, apr 20, 2016. If anyone is serious about the homebuilt amplifier, i can email them picture of the amp and transformer as an attachment to the email. A multivoltage heavyduty transformer with a unique buckboost. Many muffin fans in a pair of 3 500z amps produced 100110 cfm. Old eimac 3500z are still performing 30 years later in old heathkit sb220s. The background noise level is quite high here in io91jo, as is the competition when the band is open. Remove the tank coils l7 and l8, inductor l9, plate rf choke rfc3, safety choke rfc1, door. The correct ceramic socket to use is a johnson type 275. This is the unexpurgated, preedited version of the article improved anodecircuit parasiticsuppression for modern amplifiertubes that appeared on page 36 in the october 1988 issue of qst. Other types of modern amplifier tubes commonly used in hfamplifiers have an even higher amplification factor and a frequency rating of up to 500mhz. They are one of the most popular tubes for amps and surely someone not too far from you has an amp and they are willing to test them. Amplifier totransceiver alc works properly only on constant signal level modes such as rtty and fm. I do not have a 3500z based amp, but would like to test these tubes to determine their status before offering for sale. It is equipped with double shielding in a cabinet of thick material with sturdy handles.
My 6m station consists of an all mode transceiver, usually the elecraft k3, a my dualband 6m4m beam and a home made 3500z linear amplifier, producing a clean 400w of rf, or a solid state 300w pa producing somewhat less clean signals. The authors discuss the development of a tube tester for high power transmitting tubes and modified amplifiers that used the 3 500z and 3cx1500 8877 tubes. Linear amplifiers part 4 3500z data the original site. The hammond hla hf linear amplifier is a onestage linear amplifier using one glass envelope 3500z eimac triode. The anode of the 3 500z operates at a visibly red color at its maximum rated dissipation of 500 watts. The emac 3500z is a compact power triode intended to be used as a zerobias classab2 amplifier in audio or radiofrequency applications. They should check for shorts easy to do with a meter first, then see how they perform. The following describes a 16010 meter linear amplifier that uses a pair of 3500z triode power tubes. Two 3 500z tubes in a single amplifier, chassis mounted, may be adequately cooled by use of a fan so mounted as to pressurize the space below the. Listed under the technical referenceamplifiershf amplifiers category that is about amateur linear amplifiers. A legallimit amplifier for 160 through 10 meters 8877 arrl handbook 1990, pp. The lower diagram was for the rebuilt amplifier using a single tb3750 triode. I am not enthusiastic about the 4125a, 4250a and 4400a, with the gain on 1020 metres falling below the european tetrodes. The unit is a completely selfcontained table top unit capable of watts input.
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