The tubes are ceramicmetal, with forced air cooling. In a singleended circuit the loaded q should be at least 3. With two 4cxa tetrodes tubes in parallel, there is lots of reserve power to generate a very clean signal. Capacitance values are for a cold tube as measured in a special shielded fixture in accordance. Thus, if you run 3000v at 667 ma, thats 2000w dc input. Hfamplifier with 4cxa build into the cabinet of the amplifier with a gs31b. Ian white, gm3sek, sells kits for tube control and protection. Running the 1500 in ab2 offers 1100w output in typical operation.
Heater voltage and bias adjustment on the front panel. Here is some data on the power triodes that might be usable by amateurs for radio projects. This is done in case of equal tube type numbers for different tubes. I dont know how the 4cxa 4cx1500b tube would like that circuit, but worth considering. The following list shows the tube types i have entered in my database, with exception of the service types e.
Eimac 4a typical operating specs for grounded grid. Offered tubes soviet marks as gu74b are made in the ussr at 198092 on this svetlana factory, are full analogue and have the best parameters rather modern sv. Overview of tasks in performing the conversion, five specific needs must be addressed. My main question is can the tube be operated in ab1 according to the 4cxa specs for additional power output screen voltage at 325v vs. Technical data the eimac 81684cxioooa is a ceramicmetal, forcedair cooled, radialbeam tetrode with a rated maximum plate dissipation of watts. From an initial cold condition, tube operation will stabilize after a period of approximately 5 minutes. A feature of this tube is the integral screencathode bypass capacitor. Mechanical application mounting the 3cx3000a7 must be mounted with its axis vertical. I have used these tubes since 1997 when i purchased the alpha 91b amp that used a pair of them for a 1500w hf amp, back then i had the use of portable spectrum analyzers and never found those tube to be dirty as far as imd, like any tube when you push them beyond there limits any tube gets dirty even the omg eimac tubes as. Sk1a sk2a 4cx800a 3cx300a1, 4cx250b, 4cx250r, 4cx350a, 4cx350ac, 4cx400a, 4x150a, 8560as, refer to the 4cx800a technical data sheet for electrical connections and cooling requirements. Bill beech, nj7p has a tube database on his web site comprehensive transmitting tube data 1988 handbook base diagrams and data.
Not surprising, since i understand that many 4cxa pulls were removed from bc service because of excessive secondary emission. Hfamplifier with 4cxa amateur radio station dl2mdu. Eimac 4a typical operating specs for grounded grid operation rare on. Comprehensive transmitting tube data 1988 handbook base diagrams and data. The price is for one tube available are 3 pieces you can choose one of them. Signal warren bruene talks to us official magazine of the. You can also find the right tyre to suit your riding style. The 4cx15000j8910 is intended for use in audio or radio frequency applications. Bill beech, nj7p has a tube database on his web site. They are designed to safely withstand up to 300 watts of reflected power and up to 100 milliseconds duration of drive spikes. Also noted is the range of values for plate current for a given grid voltage can vary at a ratio of over 21 and grid over 31.
The 4cx15000j8910 is a tetrode manufactured by cpieimac. It is impossible to override the screen and grid dissipation at any. We sell nos new old stock gu74b or 4cx800 tubes used in the acom 2000a, acom, acom 1010. Make sure that all 16 of the sockets spring contacts are outside the tube, and clipped tightly against the tube screengrid ring.
The input and output tuning coils are shown on each side of the tube. The new tube needed slightly more bias voltage to obtain the rated zsac and appears to need more drive for full output. The 4x1 tetrode is an anomaly when placed in himu gg triode service. My main question is can the tube be operated in ab1 according to the 4cxa specs for additional power.
Here, you can find full details, technical specifications, advice on use and maintenance, everything a motorbike enthusiast needs. Input circuit a resonant tank circuit is recommended for groundedgrid operation. Substitutes are given as a guide only please refer to original manufacturers data sheets to ensure that a substitute is safe and appropriate for your application. Ompower amplifier tetrode fu728f matched pair for om4000hf and om4000a.
Tube 4cxa or rohre 4cxa id30545, beam power tube, transmitterbase in gneral and shown. This was a construction article describing a 4cx1500b using an untuned input circuit terminating the rf drive signal in a 50 ohm resister. This technique increases linearity and output power. Data 4tx600a formerly x 2009 the 4c x600a is a compact radial beam tetrode with low lead inductances and low inter electrode capacitances, designed for use in distributed amplifiers and in uhf service up to 0 mc. The 4cxa can only be used in class a or ab1 service with no grid current, so efficiency should be about 50%. The upshot is that the screen current is more stable than with the pulls. The data sheets specifically state when more than one tube is used they should be matched and the rca handbook suggests using per tube bias adjustment. A comparison of the published orginal eimac 8875 data and the published svetlana 4cx400 data sheet.
Cooling consists of a remote positioned large blower on a long hose which make things very quiet. The shield cover is easily removed to provide easy access to the stage, especially for tube replacement the 4cxa tube is designed to operate at maximum power without driving the grid into the positive region. The new tube needed slightly more bias voltage to obtain the rated zsac and appears to. Intermodulation distortion the radio fre quency linear amplifier operating conditions including the distortion data are the results of actual operation in a neutralized griddriven amplifier. It is not published anywhere else or recommended by acom. The price is for one tube available are 3 pieces you can choose one of them, the 2 of them must be new but i dont have the original box. All you need is a hefty choke for the mod reactor, no mod xfmr required. Om power om2501a heavy duty legal limit hf automatic amplifier. Qst for may 1977 ran an article by w2aih entitled an ultramodern linear amplifier.
While the eimac 4cxa tube data shows a recommended typical screen voltage bias of 325 vdc, the 30s1 employs a more conservative static 200 vdc bias. As of 3505, i have finished scanning the general section, receiving tubes part 1, receiving tubes part 2, miscellaneous, specialpurpose receivingtype tubes, thyratron, ignitron, and glowdischarge tubes, and most of the transmitting tubes, as well as all. The eimac 4cx1500b is ceramic and metal, forcedair cooled, radial beam tetrode with a rated maximum plate dissipation of 1500 watts. With the naming conventions of ceramic tubes, we can tell quite a bit about the unit without even looking at the data sheet. The is a low voltage, high current tetrode specifically designed for class ab1 rf linear amplifier or audio amplifier applications where its high gain and low distortion characteristics may be used to advantage plate dissipation max. There was no clear documentation that i could find anywhere on the internet, or anything from acom or any other manufacturer of amplifiers designed around 4cx800agu74b tubes.
This amplifier must be ordered directly from om power. It is a lowvoltage, highcurrent tube specifically designed for exceptionally low intermodulation distortion and low grid interception. It is a lowvoltage, highcurrent tube specifically designed for classabi rf linearamplifier or audioamplifier applications where its. Offered tubes soviet marks as gu74b are made in the ussr at 198092 on this svetlana factory, are full analogue and have the best parameters rather modern svetlana 4cx800a. Ompower amplifier tetrode fu728f matched pair for om4000. I am working on scanning and placing on this page the entire rca hb3 tube manual. Warren was always quick to point out that, under the conditions specified at the time 1 kw stage input power and, as tuned, 300 ma of plate current the. Where possible, eimac data sheets are provided, as eimac tubes are used by so many hams. This is in stark contrast to the 4cxa which states running it into the ab2 region is a bad thing. Svetlana power transmitting tetrode the svetlana 4cx800a is manufactured in the svetlana electron devices sed factory in st. Triodes 25t325a3 data sheet 194425t, 25t, 325a3 25t data sheet 195125t 35t data sheet 193535t 35t data sheet 193635t 35t data sheet 194535t 35tg data sheet 194535tg 35tg data sheet 1955tg 50t data sheet 193450t 75t data sheet75t 75th data sheet 194475th 75th data sheet 195275th 75tl data sheet 194675tl 75tl data sheet 195275tl.
Hfamplifier with 4cxa build into the cabinet of the amplifier with a gs31b show slideshow search for. The first number is indicates the number of grids in the tube, 3 makes it a triode, 4 tetrote and 5 pentode. Signal warren bruene talks to us official magazine of. There is info in the old bill orr radio handbooks on that arrangement utililizing a 304tl or a pair in parallel in a biasshift modulator. The underscore and these letters are not part of the tube type number. The internal structure features a mesh filament and a mechanical design which assures good strength and high rf operations efficiency. They are of particular interest to hams building tetrode amplifiers, which have more complicated biasing circuits than grounded grid triodes. It is a lowvoltage, highcurrent tube specifically designed for classabi rf linearamplifier or audioamplifier applications where its high gain may be used to advantage. These were often used for driver tubes in fm broadcast transmitters. The is a low voltage, high current tetrode specifically designed for class ab1 rf linear amplifier or audio amplifier applications where its high gain and low distortion characteristics may be used to advantage.
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