Gi 7b power supply Judging form the outward appearance and specifications, the GI-7B tube is designed to run vhf and uhf. Replace power supply diode/cap board with Far Circuits board and new, smaller caps 3. High voltage section. Converted the amp to use a pair of GI-7B tubes. The GI-7B with a heat sink and the GI-70B with no heat sink. Pretty much in line with the various US web pages describing conversions. A steel bulkhead (. Test with 2 ? GI-7B and an external input circuit (ATU) to obtain SWR = 1 on all bands. 6v @ 3amp transformer, the plate choke, and by-pass capacitor must be located on the plate. Filament and 12vdc power supplies. Start with around 30V and adjust up or down to achieve an idle current of about 30 Layout was the next consideration. All I have to compare it to is my SB-200, but it compares very well. 5KV no-load, 2. Power multiplication factors of 10x to 14x can be expected with 40-60w drive. The triode is available in two variants differing in the type of cooling: the GI-7B with a heat sink for forced air cooling and the GI-70B with no heat sink for other The OTK stamp is a quality stamp of the Russian army and the valve is a GI-7B in the Cyrillic. So the power indicated must have been real! There are much more advanced tubes than the GI7b. Power Supply Capacitors and New Filament Transformer The preceding describes the first Dentron conversion. Applications: General purpose applications in oscillators and amplifiers for centimetric and decimetric wavelength ranges. Has a built-in power supply, RF relay and is wired for 100v mains. The GI-7B tubes were installed and the determination was made to replace the old change over relay with a smaller and faster unit. Here is a summary: 1. My effort is no different, and it works. 5kV maximum output before significant compression appears to be about 560W PEP - well within the ratings of the valve. Initially, stability was a serious concern. My power supply is a full wave voltage doubler with 560V AC giving about 1. KG8GP I have a 400+ watt 2 Meter GI-7B Amplifier using a Russian GI-7B Triode tube working 100% for sale. GI-7B with a smaller cooler for the anode. Test with minor modifications of the schematic. I came across another tubeless 2500 and couldn’t resist. DESCRIPTION. At the price they must be the gift of the century! And they are rated to 2. The large grid band is clearly visible below the purple ceramic insulator. Oct 6, 2009 · Got the HV and LV power supply rebuilt. WD8DAS SB-230 Amplifier Tube Retrofit Project. Second of all, performance. The tubes GI6b, GI7b, GI7bt, GI70b and GI70bt are all the same GI7b. Heatsink removed, plenty of vent holes all around. Used custom GI-7B sockets, bias board and schematic provided by K4POZ. Rear view. There are many GI-7B ccts about. Aug 23, 2013 · Partly finished conversion with a doubling power supply, a 12. The GS-9B is a very similar tube used for signal amplifiers. Fig 4 above shows RF Power Amplifier Tube Performance Computer model of Class AB2 operation along the load line. May 30, 2024 · - polypropylene capacitors (MKP) in HV for GI-7B output tube - regulated power supply for all stages (for the output stage as well) - automatic bias current control for the output tube with long term stability - switch selector for up to 100W or 40W of power output (with switch position on rear panel) The GI-7B (GI-70B) microwave triode operates as an oscillator and an amplifier in continuous-wave or pulsed mode with anode modulation in the centimetric and decimetric wavelength ranges. Here you can download the schematics from the RF part: HF Teil. Timer board and power supplies were all tested. The GI-7B tubes run tremendously cooler than the original 572B tubes and extremely cool for an amplifier of this power level. and a small muffin fan running at reduced voltage. Sep 20, 2010 · Actually, on HF, I have seen as much as 550 watts (into a dummy load, of course!) from a single Gi-6b. Estate find turned into a labor of love. The GI-7B tubes have 12. The GI (“Generator Impulse”) designated tubes are designed for the very high pulse strength required for RADAR transmitters. Linearity is very good as measured on my trapezoid scope. The project started as a retrofit of the Clipperton with GI-7B tubes. It was mounted much lower in the same location. The following describes a few changes in this second conversion. sch. Can be used in HF to 70cm power amplifiers. This and size limits me to the 225W output, but at 2. Just by doing that the amp is putting out 35 watts on 40 meters! Not resonant in it's current condition. . And, as with all of my amplifiers, it has been given a name and this one is Piglet. Partly finished conversion with a doubling power supply, a 12. But if you think a bit about sockets, screen voltage supply, high pressure blower - you give up easily. I was probably power supply limited, using the power supply out of my FAA single 4CX250B amplifier. The design above is based on as assumed DC supply and expected power output. The GI-7B (GI-70B) microwave triode operates as an oscillator and an amplifier in continuous-wave or pulsed mode with anode modulation in the centimetric and decimetric wavelength ranges. 2KV @ 0. Has Kenwood TL-922 HV transformer with Harbach soft-start and new Heathkit SB-220 Harbach replacement power supply board. It is tight but will fit. 73 Brian A. Got to work on the bias supply next and then on to the band switch network. Also designed for forced air cooling with a heat sink. 8A (400mA Per tube), key down. Comment The most common tube used for replacing the 8873 in this amplifier is the Russian GI-7B, a VHF power tube originally used in Russian RADARS. The tube was temporary mounted on a base of a defect 3-500Z for eventually testing in my FRI750 PA. The bias diode checks good so that is a plus. As mentioned, my SB-200 nets me a 800 watts with its improved power supply board. I think it would be great to have a light weight amp for hf. Top view of the power supply for the two GI-7B cavity amplifiers. The anode fins can only be described as substantial, they are also silver plated. The amp was custom built by Carey/KC5GTT and is one of the more popular ones for 2 meters. 5GHz+! Panasonic microwave inverter power supplies for an amp hv supply, he tested it out but the regulation was wrong and it had insufficient filtering. This has nothing to do with the Disney movies, i decided on Piglet as I consider the amp to be the daughter of my GS35b amplifier that acquired the name 'The Pig', the reasons for that can be found elsewhere on my web site. The GI-7B, a 12. The valve has few connections, it is a directly heated triode. Replace 4, 572B tubes with 2, GI-7B tubes 2. For a few $ more, a robust version is available, the GI-7BT designed for tropical climates of high temperature and humidity. Nearly two years ago I bought four G1-7B tubes to make another linear amp. GI-7B Bias Voltage: Due to significant differences between GI-7B tubes (new and surplus), and because plate voltage can increase significantly from full load no load condition with some power supplies, it is difficult to predict exactly what bias voltage to use. Air-cooled Russian GI-7B triode replaces the conduction-cooled 8873. Much of the idea comes from Fritz at pa0fri, a mine of info. The wattmeter pick up circuit was remounted between the wire coming off the end of the tank coil and the relay (see picture). 5GHz+! The GI-7b, GI-70b and GI-7bT microwave triode operates as an oscillator or an amplifier in continuous-wave or pulsed mode with anode modulation in the centimetric and decimetric wavelength ranges. Install Heathkit SB-220 HV transformer 4. It is 2. LA-1000 with a bad power supply that I'm going to re-tube to a GI-7B Russian triode. Anode supply was about 850 V on The GI-7B microwave triode operates as an oscillator and an amplifier in continuous-wave or pulsed mode with anode modulation in the centimetric and decimetric wavelength ranges. So far the GI-7B has proved to be a great tube. The tuned input and the tank circuits were all good as checked with the AA30 analyser. It was groaning pretty vocally With this linear you can make 350-400 Watts on SSB. The GS The GI7b amplifier in its finished state. For your own scenario, you can follow the same procedure to develop a design suted to your own needs. Your own scenario. The GI-7"b" is available in two variants differing in the type of cooling: the GI-7b with a heat sink for forced air cooling and the GI-70b with no Here are some comments and pictures. I was surprised when the SB-230 measured in at a good 900 watts with its original power supply. All enclosed in a beautiful blue powered coated case. The blue colour marks the details. Some variants (GI-70B) may not have a heatsink and are intended for different cooling systems. Under the RF chassis. 6 VAC filament transformer and 2 × GI-7B. 4 kV on load. 6 volt filaments so a filament transformer has to be somehow shoehorned into the amplifier. All indications are that the tubes run clean when managed properly. 35 to 1. It's a doubler with huge capacitors (8 x 1900 uf) and small transformer. Top view. Progress was good and I estimate I was a couple of weeks away from full on testing. I sold this linear, after a longer usage. You may possibly build a HF amplifier with the information in this article. Took out all the garbage that was installed. Here is the schematics for the bias control. The well-known 4CX250B has almost the same dissipation and power range and needs less drive. By modifying this amp were minimal changes to the original design and as far as possible minor initial components used. My own power supply and timers etc may be different and the layout of course is always a head scratch but the fundamental RF circuits are all similar. However, the more I worked on it the more changes I made. Re-activation. and I happen to have an Amp Supply Co. The replacements are NOS, and available in abundance via the internet at reasonable $/watt prices. Here you can download the schematics from the power supply: Netzteil. 028” thick) was fabricated and placed between the power supply components and RF compartment to better isolate the two functions. The triode is available in two variants differing in the type of cooling: the GI-7B with a heat sink for forced air cooling and Figure 6 AA4PG 3/30/2013 [email protected] Page 6 of 14 Power Supply Capacitors and New Filament Transformer The preceding describes the first Dentron conversion. nnx vgjj wet rwnpnz lhvvl sitxu qzrxzj tosmn fsnv rjqj