Gi7b amplifier

Gi7b amplifier. Rated at 1200 watts PEP INPUT typical. IMPORTANT NOTE: ALL connections between RF parts, and ALL connections to ground (!), MUST BE as short as possible! The GI7b (LD7) is also good on 23cm. This tube was originally developed by the Germans during W. Go to www. Most modern HF/6m transceivers are capable of 100 W PEP at 50 MHz. Heatsink removed, plenty of vent holes all around. Check Details. 5G POWER AMPLIFIERS. Aquí está la descripción de mi ampliador con tres válvulas GI7B. HAM konstrukce. 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 This is a forum dedicated to the discussion of Ham Radio Amplifiers. The A pair of Gi-7B tubes are wired underneath similar to Fritz, PA0FRI. I have made the most of the propagation which has been up and down but worth the effort, as I put out some nice signals into North and South America as well as the Caribbean. 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. Here are the steps after removing the 8875 sockets. Under those conditions the amplifier can operate continuously at 125-150w output. Consider it a nice amp for AM operation and being that 25 watts is linear off a 100 watt amp in AM that is all you need for a decent 400+ output and a low foot print. Notes from the schematic diagram. 4% negative feedback. Here is the high-voltage generator for testing before the start. Acom 600S HF Power Amplifier - Solid State - Ham Radio - HF This document provides instructions for modifying a Dentron MLA-2500 amplifier to operate with GI7B tubes. 600+w pep with 75-80w pep drive. 4 in. Aug 22, 2011 · Radio station OZ1PIF. V roce 2006 jsme s Jakubem OK1FVN dostali za úkol poradit si s 2m PA 1kW s GU43B, který vykazoval vysoké vstupní PSV při zaklíčování. Jan 8, 2023 · Amplifier gi7b 50mhz 6m yu1aw amplifiers gs35b schema building Amplifier hf2 x gi-7b 6m pa Amplifier linear hf gi 7b cb 10mAmplifier hf wzmacniacz mocy. ) which tend. 23 W, 10W wire wound resistor added to bring filament voltage to proper 12. Tube 1 - 7289 #1. The amp has the following upgrades: 1. The result is a family of 6m & 2m PAs which use standard inductors and capacitors rather than tuned lines in the Hello. Solid State Amp. The GI-7B with a heat sink and the GI-70B with no heat sink. 9 x 0. Rear view. The seller is "spitfirecbs" and is located in Gloucester. The fan is mounted against a 1/8" thick soft material to reduce noise and any vibration. Gary. With a good matching in the cathode circuit only 1015W of drive is needed. Filament and 12vdc power supplies. The best output that I’d heard of from an 8560 conversion will be 300 to 400 watts. Dimension. Feb 9, 2022 · SOLD! MLA-2500 converted to a NOS GI7B tube. to some changes for the tube capacitance. 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. A 12v fan is mounted underneath blowing upwards and cylinders surround tube anodes to contain airflow. Array Solutions Power Master. New power cord and power supply rebuild, Harbach soft-start wired for 120VAC and keying mod for 12VDC @17ma. Scroll down to see pictures and narrative describing GLA-1000 converted to use the Russian GI-7B triode, below the schematic diagram and notes. Sep 12, 2021 · Clean SB-200 converted to GI7B tube. Harbach soft-start wired for 120VAC operation 4. Can be used for mobile or base amplifiers. Looks nice too! Made in America, by an American!! 144MHz PAs designed using HF techniques by. I also h It is well known that 23cm PAs using Russian GI7b / GI7bt tubes suffer from thermal drift and can oscillate under certain conditions. PicClick Insights - GS-9B same as GI-7B Tube Amplifier QRO HF VHF UHF TRIODE GI6B Military equipment PicClick Exclusive Popularity - 3 watchers, 0. Amplificatore lineare con 4 valvole EL Amplifiers SB F1CXX - 2. The end result is a convenient sized tabletop RF amplifier that will easily produce 800-1200 watts out. Recently the amplifier was optimized, the tubes were matched, so now they work together (and heating gi7b is tube designed for microwaves but working good as hf amplifier idea is to build cheap reliable hf amplifier covering 160 meters band . Quiet power switching relay prevents ON/OFF switch failure. Avg: $187. . I drove 20 watts of RMS watts into it and about 120 watts swing pep and saw 600 dead key watts with a swing of 1800 + mw watts on a bird peaking meter. View our line of stock and custom amplifiers available. This one fits right under my metal bakers rack along with the MLA 3000 tuner. Here is almost finished assembling you remarquerais the capacitor plate manufacturing house also. Added 4n7 bypass at HV glitch resistor. Amplifier Type: Low Noise Amplifier. 2200 volts on the plate, about 350 watts output on SSB. Weight. Rerouted variable capacitor VC1 ground path. Apr 4, 2023 · Very clean SB-230 from nonsmoking environment converted to a single GI7B tube. Band VHF PA 5 Watts, GJ4ICD's 8877 50MHz Amplifier, 6M QRO. GS-31B. All the Best. #4 The cathode-filament connection is on the top of the PCB. Replacing the capacitor board to make room for a 12V filament transformer while using low-profile capacitors. The filament only draws 2 amps so it produces less heat and uses less power. This item is in the category "Mobile Phones & Communication\Radio Communication Equipment\Ham/Amateur Radio\Ham Radio Amplifiers". Clean Yaesu FL-2500 amp converted to a single GI7B tube. Tento PA je na fotografiích jinde na našich stránkách. This construction article appeared in 1987 in Radiotechnika magazine (Hungary). you can have an idea on my youtube channel "Dimitris Bel" YouTube Please check and sent me your comments. CT1DMK wird aber versuchen, die Ursachen zu ermitteln. Oct 24, 2016 · About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright This page describes the construction of a 1500-watt 2m amplifier using an 8877. Applications: General purpose applications in oscillators and amplifiers for centimetric and decimetric wavelength ranges. can be used with the original chassis. 73. 0: 35-TG Aug 24, 2013 · Russian Tube Amplifier By W Mountain Top Electronics single 7B amplifier under test. 6m amplifier with 2x Gi7b by 9A3MR This is my contribution to cheap tube amplifier gallery. Amateurs with these lower power radios will find this amplifier an excellent addition to the shack! 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. You *must* login first, using the 'Login' link at the top of this page. SO-239 and bird mounting cut out . a pair of tubes would run you about $60. 0. It cost of HK$215. $1000 ea. Apr 2, 2005 · Built with actual sockets to enable easy service in the future. The GI7B is a Russian triode suitable for operation at 13 and 23 cm, as well as 6 and 2 meters. There's hardly anything new to add about grounded-grid triode amplifiers. Initially, stability was a serious concern. More. The modifications include: 1. 2008 napsal OK1GP, OK1UBO. Hf 40mt kwGs35b amplifier low Hf power ampsYu1aw gi7b 50mhz amplifier. The open amplifier seemed suitable for modification to accommodate the Russian valves GU-43B, GS-35B or GI-7B to get more output. Starting with the Yaesu FL-1000, the companion amplifier for the Yaesu "F" line. Metering. Diode protection on meter & LED meter lamp 7. The design follows the classic W6PO design which is described in the Eimac Notes. Comes with a spare NOS tube and bound copy of manual. E: CT1DMK developed that PA, and I made a copy of it with many photos. the amplifier detuning because of grid heating. Opens in a new window or tab. Under the RF chassis. Has provisions in bottom panel for rubber cabinet feet . Se inscreva em nosso canal!Deixe seu like! Clique no Jóinha!Em breve Next amplifier Last modified 2022-10-06 Drake L-4B SPECIFICATIONS. ×. High amount watching. New 12 VDC T/R relay---17ma keying 6. I have used this amp with numerous radios and it always has preformed for me. 3. Auto start, Forced air cooling, 120v plug in wall, tuned input, HAS SOCKETS for easy tube replacemen Search Amplifier with DuckDuckGo or with Bing. Jul 8, 2021 · Just a quick look at some of the VK5ZOO and VK5MS amplifier bits, and theres quite a bit more. Jul 5, 2021 · Today I made the new valve mounts which should help with dissipation of the heat as well as provide RF shielding and a direct grid connection. Amplifier linear gs35b hf wiring completed switch before been so now hasAmplifier hf 40mt Gs35b-hf-amplifier_10_15_20_40mt-1,2 kwGs35b 6m amplifier. Konstrukce. The excellent YU1AW contributions to the cadré of GI-7b PAs is presented here. SSPA 432 MHz 500W. I run it on 120 VAC, and it runs cool and stable. I recently bought a used one on-line at a reasonable price. With approx 40w SSB drive, output is approx MLA-2500 GI-7B Tube Sockets using 8875 Holes. 0 new watchers per day , 480 days for sale on eBay. It cost $95 dollars including the entire cutting fee. This amplifier was rated at 1000 watts INPUT, not output. The amplifier was designed by Gabor Draskovits, HA1YA, who produces similar amplifiers commercially for export. Seller - 4,513+ items sold. All the mechanics were done by Erich, DJ7LH with my I hate large, tall amps that get in the way. days. 120 watts AM using 9 watts of drive from an H The GI7b amplifier in its finished state. This enhances Sep 26, 2017 · The item "Yaesu FL-2500 HF Amplifier converted to 2 x Gi7B Russian Ceramic Triodes" is in sale since Sunday, October 21, 2018. GI7b Linear. GI-7B. 0: 3CX3000F7: 46: Push-Pull RF Amplifier Circuit from 1930's (75 Watts) Chapter from the Radio Handbook of, apparently, the 1930's; "Medium and High Power RF Amplifiers" (See figure 1 for this amplifier) 50 - 100 Watts: 31. When these amplifiers were sold the rules stated power input as the legal power. This review is of a Dentron GLA-1000B that has been converted to use a single GI-7B Russian ceramic/metal triode. $40. Additionally, designs using the GS-31B and GS-35B are aslo shown. #3 The spacing between the top plate and PCB is 1". WD8DAS SB-230 Amplifier Tube Retrofit Project Air-cooled Russian GI-7B triode replaces the conduction-cooled 8873. W. or Best Offer +$12. All this home made. Technical Characteristics: Ouput Power 2KW, Power Gain 13dB, Anode Voltage 4500V, Anode Current 1A, Grid Voltage 42V, Grid Current 300mA, Drive 100W, Harmonic attenuation > 55 dB. El proyecto empezó buscando por Internet y gracias a la información proporcionada por YU1AW y JH0WJF. The box is ran on 120volts AC with about 15 amps of draw AC. Installing the filament transformer and a glitch resistor for fault protection. This is my contribution to cheap tube amplifier gallery. 0: 35-TG The high voltage. Type: Amateur HF linear amplifier: Frequency range: 10-80 m: Output power: AM/CW/RTTY: 700 W SSB: 1 Apr 4, 2013 · Single GI7B Grounded Grid home brew 6 Meter Amplifier. GS-35B. Tested with approx 65w SSB drive on 80m and output was approx 700w. Here we have another linear with 2 valves GI-7B. However there are still a lot of very good, but older transceivers on 50 MHz that run only 3 -20 W. Has quality K4POZ socket & bias board, new 12 volt filament transformer with solid-state timer for 90 sec filament warm up, new larger electrolytics in the power supply, new cooling fan and new 12VDC T/R relay & 17ma keying. NOS pair of GI7B tubes with quality sockets & adjustable bias board from K4POZ. YU1AW. UHF LINEAR AMPLIFIER 432 MHz WITH TH328. VHF LINEAR AMPLIFIER 144 MHz WITH TH328. G0MJW Hf 6mt 2mt 70cm 23 cm 13 cm. 04-sep-2023 PA3HBT's GI7B conversion. 8. Close. 65, Low: $17. A TS690 puts out 50 W and is an excellent 6m radio. II for self-oscillating radars, and it was copied by the Russians after the Title: GI7B GI70B Author: Electronintorg Subject: JA-2003-01-16 Created Date: 12/14/2002 7:52:05 PM Feb 27, 2023 · HF Amplifiers. Please contact us to discuss your needs. Jul 2, 2018 · This is why many of the 2500/2500B's were converted to GI7BT's or single 3cx800's also 4cx400 Svetlana's (also no longer in production)if you find one with good set of 8875 tubes, be aware when driving those amps the grids are fragile plus certainly NOT for AM usage under any conditions IMHO. Millimeter-Wave RF Amplifiers, Low Noise Amplifiers, High Power Amps, Full Band Amplifiers, and More. 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. (higher dissipation because of high freq. Does not have 160m capability, not physically enough room for plate tank components. Call or email to see what is available to purchase now. Idea was to build stable and small power amplifier, suitable for portable and domestic use. small labs f5mag rf concept gi7b 1500 w GI-7BT Triode NEW Tube power amplifier QRO HF VHF UHF GI7BT GI-7B GI7B. 2 x 0. I have make some tests with ceramic russian tubes 6S17K-V GS-13 GS-4V and GI-7B. The majority of amateur radio designs using these tubes are based on 3/4 lambda cavities, the famous CT1DMK design being the prime example. United States. This bottom section will mount. lower and may reduce this effect. New front panel overlay makes it look like a new amp. 73, Homebrew GI-7B Sockets. The K4POZ sockets are excellent and. 2 tube GI7B ( not available ) This is a 2 tube GI7BT. Toroidal transformers is used. NOS - Set of four Russian GI7B tubes, and sockets. With 50w drive, puts out 500-600+ watts, 80-10m depending on band, drive power and CW/SSB HV switch setting. coupling input to the cathodes and no tune input circuitry. All indications are that the tubes run clean when managed properly. Very clean audio. May 20, 2024 · The SB-200 uses a pair of 572B tubes, which can put out a nice solid signal approaching 600 watts (output) with 100 watts of drive on CW. Water cooling is required at these power levels. 6m amplifier with 2x Gi7b. from Ukraine. Feb 24, 2018 · audio amp with GI7B GI-7B Hi. These amplifiers commonly exhibit thermal instability and low efficiency. com. Video explains it all. Apr 24, 2024 · NOS - Set of four Russian GI7B tubes, and sockets. and a small muffin fan running at reduced voltage. Potentially addressing issues with loading on 160M and 80M FL-2100Z modifications. Sep 25, 2021 · 600 to 700 watts out of my SB-230 with a good 8873. My first encounter with this tube was generously helped by G3MY, who supplied details and photos of his single tube six-metre amplifier. Je n’ai pas la prétention d’apprendre quoi que ce soit aux autres, mais après beaucoup de The GLA-1000 is a great amp with a small footprint, easy to convert, and reliable. I start at first with one Russian GI7B tube. The GI-7B tubes run tremendously cooler than the original 572B tubes and extremely cool for an amplifier of this power level. 20 ft - 1 inch aluminum angle and cut into small section for building the chassis of the GI7B amplifier. The first change was to use the original 8875 socket holes. This page shown only for historical reasons, the amplifier is no longer in my possesion, but has found a new home at OZ6YM! The saga about my 144 MHz GI7b Linear: In 2000 I acquired a second- (third or fourth) hand job, originally built by HG8UG, bought in DL-land from DG5NFF (I believe) by OZ1BNN last year. is. Features: 1) High Gain- 23d B. $19. A 144 MHz GI7B Power Amplifier. G-811 same as 811A Triode NEW Tube power amplifier QRO HF VHF. 120v plug in the wall. The efficiency is same as with 70cm configuration or around 50%. Best price and value when compared to PicClick similar items. Addition of a + 10 Ω/15 W non-inductive resistor (R) is a simple way of correcting the overdrive. 420w x 155h x 480d mm³. 144 MHz PA s 2x GI7B. New complete Harbach power supply rebuild includes electrolytics, rectifiers, metering and bleeder resistors. Listed under the Technical Reference/Amplifiers/HF Amplifiers category that is about Amateur linear amplifiers. We often have some units ready to go! PA HF QRO AVEC 2 GI7B Préambule : Voila la description d’un ampli pour les bandes amateur, avec une base d’un ancien PA bande libre. First, remove the bottom section of the K4POZ socket. The amplifier uses 16 MRF150 MOS FETs in 8 push-pull output stages, which are driven by a push-pull stage using two additional MRF150s. Lead times can be long due to the state of the industry. As with all of my amplifiers, it has been given a name and this one is Piglet. Quality K4POZ tube socket & bias board 5. The GI-6b triode is designed for use in microwave oscillator circuits with no external feedback, providing continuous wave or pulsed operation with anode modulation in the decimetric wavelength range. Description: NIC introduces its Wideband LNA designed for C Band, Radar and Satcom applications. + $12. This amplifier operates in the frequency range of 4 GHz - 5 GHz, providing high gain, low Noise Figure and is built in an extremely small package size of 1. Dimensions: 12 1/4" x 13 1/2" x 10 1/4" This cabinet IS designed for a compliment of GI46B GI7B GS31B or power supply And more. This converted amplifier requires less drive than the 100 watts many transceivers provide. The ceramic 8875's are nice with 20-40 watts drive. For the 1296 MHz, the GI7 may have problems regarding. Los problemas mecánicos son sin duda el principal problema en los amplificadores de RF, debido a los cambios térmicos, ventilación Jul 3, 2021 · With some expert assistance at hand I am redesigning the valve housing and cooling system as well as upgrading the anode/cathode connection points. #1 The top plate (grid connection) is 3" square; the hole is 1 and 7/16" diameter. Price: $0. Resources listed under Amplifier category belongs to Amplifiers main collection, and get reviewed and rated by amateur radio operators. Although measures are small, this PA delivers 900W with used pair of tubes primary installed into amplifier. 00 shipping. GI7b 1296MHz 500W-Amplifier by CT1DMK (original page) Datenblatt der GI7b. New technology parasitic suppressors. I am currently using it with an Yeasu 897D I am converting a solid state medical research amp for amateur radio use. GI-7BT. 16 100w linear amp using four 807's At a Dutch rally I once saw an open Heathkit SB-200 HF linear amplifier. . Je ne suis que débutant dans le monde radioamateur, et mon apprentissage est loin d’être fini…. 4. Bonjour et 73 voici la description mon amplificateur HF équiper de trois GI7B le projet à débuter en parcourant le web je consulter le cite de yu1aw sans le quelle ce projet n’aura jamais abouti étant électronicien de métier je ne pas connu des lampes les caractéristiques et les Average delivery time to. Voila almost finished. power output will run 450 watts or slightly more with good strong tubes. Goran Grubisšic, 9A6C. GI7B amplificatore lineare 1. 00. #5 The grid plate is mounted 5/8 to 7/8 May 29, 2023 · About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright Im Moment konnten die genannten Daten nicht in jedem Nachbau erfolgreich reproduziert werden. In grounded-grid style with 3/4-wave coaxial-tank, at a plate potential of 1500V and Ia= 300350mA. An RF-negative-feedback voltage will be developed across R when the GI-7B amplifies RF and reduces the driving voltage developed at the cathode. Brand New. Add Your links or post a photo of your amplifier. 1. Amplifier hfG6lbq ham radio blog for homebrew projects: a hf receive rf pre Radioworm: circuitsLinear gi7b tube selfmade coils cooling roller switchable induct pi hat filter because case two. 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 Home made 6m amplificateur avec le GI7B, by F5MAG. I suppose you could rethink the amp, use the 8560AS as designed as a grid driven amp but adding a screen supply plus changing the input network will take a lot of work. Cooling: Also designed for forced air cooling with a heat sink. The GI7b was my choice of tube due to its proven abilities, low cost (some 15 Euro) and solid 13 dB power gain. W2DTC's HOMEBREW 3CX3000F7 TRIODE GROUNDED GRID HF LINEAR AMPLIFIER: Schematics at bottom of page: 5,000 Watts: 20. The pwr gain is still around 1213 dB or more. I'll be back w GI-6b. Regards Dimitrios It is impossible to override the screen and grid dissipation at any working conditions. Price - YAESU FL-2500 Amplifier Upgrade Manual, with GI7B (T) Tubes. If you know more than I do, and that would not be hard as playi Jan 29, 2024 · Olá amigos, neste vídeo veremos a prévia de um projeto de amplificador linear valvulado. Top view. Plus shipping. VHF PA 6 m 2x GI7B. Jan 11, 2022 · Clean, from non-smoking environment, GLA-1000 converted to NOS GI7B tube. YAESU FL-2100Z Linear HF Amplifier Mod. The cylinders are from rainwater down pipe and split for easy removal/fitting. #2 The PCB (cathode & filament connections) is 2" square; the hole is 5/16" diameter. All units have tuned input, AB Biasing, SSB delay, HV and Plate Current Metering unless otherwise mentioned. New power supply board assembly 2. hamradioamps. 2 sold, 0 available. La construcción empezó por el chasis. I usually use 80 watts to drive this amp and see 600 watts PEP out on 75 and 40 where I primarily use this amp. Housing. Water cooling keep the tube temperature. 2. High quality black eloxial aluminia. Structure: Features a larger, more robust ceramic structure (around 47mm diameter). All this with a $20 tube, the GI7b. SSPA 2m 1 KW MRFE6VP61K25. The current drain is 8 amps at 240 VAC or 16 amps at 120 VAC. Ymmv. Mar 15, 2023 · Test of the MountainTopElectronics two tube GI7bGreat little russian tubes. Gi7b hf linear amplifier. UHF SUPER AMPLIFIER 432 WITH YL-1056. 100K W, 2W resistor added to cut off plate current in standby. Tube prep and notes. 09, High: $1,913. Has the following: 1. I run the SB230 when I don't need power of my Alpha 76PA or heat of my Drake L-4b. The chassis’s dimension will be at (360mm D x 350mm W x 200mm H ) Cut six pieces of aluminum sheets for the front panel and partition for the chassis. VHF linear amplifiers category is a curation of 61 web resources on , 2 m. based amplifiers to fit into your needs. 6V. Tubes and parts are found easily on the internet. a 50 mhz stable and small power amplifier suitable for portable and domestic use this rf power amplifier delivers 900w with used pair of tubes primary installed into amplifier . (by Tom/ES2RJ). The "Easy-Build" ( "EB") PAs are Linear Amplifiers designed using HF design techniques. Install HV glitch resistor + fast fuse. 5. All-mode HF linear amplifier Class AB2. 90. Email wb4 6m amplifier with 2x Gi7b. Jan 25, 2024 · Amplifier linear hf gs35b radio 1394 jet aircraft previous. SSPA 23 cm 200W- BLF6G15LS-250. PA 6 m GS35 b. Oct 15, 2018 · The last two weeks have been interesting on the bands especially with the new Russian GI7B x2 amplifier in line and working well. A small test vacuum with a probe divide by 10 manufactured by f1btm Below are the measuring instruments and IP ig. Great seller with very good positive feedback and over 50 ratings. Have one to sell? W4EMF - GLA-1000. This model, first marketed around 1965, still features in many amateur stations. Listed under the Technical Reference/Amplifiers/VHF Amplifiers category that is about Amateur linear amplifiers. Output, SWR, Plate current, Plate voltage, Screen & Grid current / voltage. High voltage section. 20. VHF PA GS35B - YU1AW design. Technické články. The youngest 2C39/7289 tubes are 26 years old now, and even with unused ones, there is quite a variation in performance (see test data below). Can be used in HF to 70cm power amplifiers. not so easy as with some tubes, hi!). 9. The tubes GI6b, GI7b, GI7bt, GI70b and A pair of Gi-7B tubes are wired underneath similar to Fritz, PA0FRI. A single GI7B tube has the same output as 4 of the 811a or 2 of the 572b tube, readily available and higher quality and lower cost. Time Owned: 0 to 3 months. Jan 23, 2024 · GI-7BT Triode NEW Tube power amplifier QRO HF VHF UHF GI7BT GI-7B GI7B. Sep 24, 2023 · Converted a Yaesu FL-2100B amp from the original (and expensive) 572B glass tubes, to the plentiful, durable, and inexpensive GI7B ceramic triodes. bj bc df uh dp xz od wj fi fw