Kenwood tl922 linear amplifier 2 x 3500z eimac valves. Amazon mp3 downloader amazon mp3 downloader 1 amazon mp3 downloader 1. It is equipped with double shielding in a cabinet of thick material with sturdy handles. Many muffin fans in a pair of 3 500z amps produced 100110 cfm. The following describes a 16010 meter linear amplifier that uses a pair of 3 500z triode power tubes. The transformer which powers this circuit was bolted to the side panel on the top of the chassis. The amplifier features fast warm up and 1500watt rf output with 100watts of drive. I have a commercial 3z amplifier i just put a 4z tube in, works fb, but drive went up. The 3500z is a relatively inexpensive tube and has been around for a long time. 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. There are many eimac 3500z hf amplifier plans in the eimac application notes and older bill orr radio and arrl handbooks. Describe your experience with the amp supply lk550 3 x 3500z and tell us why you give it the rating you did required. After the article circuit improvements for the heath sb220 amplifier was. I used to build swamped grid driven one and two hole ab2 4x1 amps to order when local bc pulls were available.
Amplifiertotransceiver alc works properly only on constant signal level modes such as rtty and fm. It is capable of the maximum legal power input level, watts dc, and can develop up to 2000 watts peak input during ssb operation. 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. The 1200 is the solid state version of the z and kinda the a. Dc relay system for humfree operation, requires shorting contact to. The anodecircuit must transfer energy and the circulating current.
The lower diagram was for the rebuilt amplifier using a single tb3 750 triode. The hammond hla hf linear amplifier is a onestage linear amplifier using one glass envelope 3 500z eimac triode. The heathkit sb220 hf amplfier and its pictorial kit assembly book is a good reference for the parts needed and typical construction. Other useful information would include your experience with similar products, infomation on a product that you would purchase instead of this one, and so on. B of power supply is floating and grounded only through plate meter m 2 and the 50 ohm salety resistor. Take another look at all of the grounded grid tube amplifiers that can run in class b and still do a fine job of keeping the harmonic and intermod numbers down. The types of problems needed to test for are described, including open. Eimac 3400z grounded grid linear amplifier build for amateur. Terminal blocks three 12 terminal barrier strips or equil. The terminal strip to the left of the 3500z socket contains the 28 volt rectifier and delay circuit. Al80b instruction manual 1 features the al80b uses a rugged, inexpensive 3500z tube. Eimac 3400z grounded grid linear amplifier build for. After modeling the circuit, i built and tested it using a hp network analyzer.
The hammond hla hf linear amplifier is a onestage linear amplifier using one glass envelope 3500z eimac triode. Nos eimac 3500z shows up about once a month, taylor 3500zg has an instant supply of tubes, of course. About 3500z amplifier project the resource is currently listed in in a single category. Nos eimac 3 500z shows up about once a month, taylor 3 500zg has an instant supply of tubes, of course. I added a 10 pf capacitor in parallel with the 110w resistor at the output of the circuit to better simulate the 3. Cabinet of power supply should be grounded to amplifier cabinet as safety measure. Qex mayjune 2016 3 ron berry, wb3lhd 326 sunset drive, bethel park, pa 151021442. Perhaps the builder would like to build a monoband amp first, to gain experience and confidence, before proceeding to a more complex multiband design. The result is cooler operation and longer component life. 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. Software use analyses software catalog 22 march bigfix. When a single 3500z is driven by 100w, it flattops and produces distortion. The elmac 3 500z is a compact power triode intended to be used as a zerobias class ab 2 amplifier in audio or radiofrequency applications. It is designed with good quality components and there are separate transformers for the hv and filaments.
Asking me about my amplifier is like asking a cber about theirs no pun intended. Building your own tubetype hf amplifier, doing it the right way. Amplifier totransceiver alc works properly only on constant signal level modes such as rtty and fm. A 25 ohm lowl cathode feedback resistor will make a 3 500z linear with 100w of drive. I measured the filament voltage in a factorybuilt single 3500z amplifier. A onekilowatt amplifier using a 3500z 183 ml rfci capacitor bank r5 ui fan top view. The 3500z requires only a few seconds of warmup time. The taylor are stated to have a 600 watt plate vs the eimac 500 watt plate, but needs extra cooling. The following describes a 16010 meter linear amplifier that uses a pair of 3500z triode power tubes. Any 4 gg amplifier schematic can be adapted to the 3z.
A dynamic bias circuit eliminates hundreds of watts of unnecessary heat generation in the power amplifier tube. A multivoltage heavyduty transformer with a unique buckboost. Bill orrs radio handbook has a two stage amplifier, a 4cx250 driving a 3z. A onekilowatt amplifier using a 3500z arrl handbook 1972, pp. This is a mono band 10 meter amplifier with a 3500z tube. Bias was set so just a bit of ig was visible on voice peaks so this wasnt deep into ab2 but more than ab1 where efficiency sucked at a really zero ig. A 25 ohm lowl cathode feedback resistor will make a. This amplifier only has a tuned input circuit for the 20 meter amateur band in. The al80b uses a single 3 500z tube in a class ab2 grounded grid circuit.
The final schematic includes the relay control circuit and 28 volt power supply. Using 2 3500zs in grounded grid arrl handbook 1971, pp. 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. The american radio relay league arrl is the national association for amateur radio, connecting hams around the u.
An 811a 200watt groundedgrid linear amplifier one 811a arrl handbook 1968, pp. Here, you must decide if you want an allinone, desk top amp, or a floor console, or a twopiece unit. The elmac 3500z is a compact power triode intended to be used as a zerobias class ab 2 amplifier in audio or radiofrequency applications. The 3400z, the 3z, and the 3cx1500a78877 eimac triodes are perfect examples of clean linear amplification devices capable of running in the class. The need for radio ham operators who use a vacuum tube power amplifier to test new or used spare tubes is addressed. This amplifier only has a tuned input circuit for the 20 meter amateur band in this video. 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. I am very impressed with the rf power the tube can deliver to the output.
Michigan scientific corporation amp configuration tool amp configuration tool. When a single 3 500z is driven by 100w, it flattops and produces distortion. The 3z is like an 8877 3cx1500 not a whole lot of drive for a whole lot of pout. Old eimac 3500z are still performing 30 years later in old heathkit sb220s. Mine is switched cap on the in and output of the pi, and a roller inductor for tuning. The 3 500z is a relatively inexpensive tube and has been around for a long time. 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.