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Vacuum-Tube Valves Circuits
Vacuum-Tube Valves Circuits
Tube 3TF7 Current Regulator
Here are design data for a 3TF7 replacement. Design was based upon the information found in The Ballast Tube Handbook` by Jacobi and on the descriptive field of the R-390x part list: Actually, according to the voltage charts of R-390x receivers, the 3TF7 gives approximately 12 Vac at its output, with an input voltage around 26 Vac.
Tube Tune-A-Lite ID37856
The following two photos show the I/V charactereristics of the main Anode/Cathode current for the Tune-a-lite 4 element neon tube used as signal strength meter in some Fada Radios as the Tune-o-graph. The 4 terminal Tuneon tube used in some Cossor radios works similarly to this tube. This first photo shows a low 130V trigger voltage for the main c
Tube AM Modulators
Hybrid Tube Radio
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Tube Regenerative Radio
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Vacuum Technology for Home-Built Gas Lasers
Many areas of scientific research and industrial production require vacuum conditions - where most (or as much as possible) of the air has been removed leaving little or nothing behind. While written specifically for the needs of home-built gas lasers, much of what follows is applicable to other medium to high vacuum systems and includes some...
The Fetzer Valve
Tthe circuit has enjoyed popularity as a standalone booster and as a building block in larger circuits. While the circuit has its merits, we decided to further explore it to determine if it was a truly faithful solid-state version of the familiar input stage used in many tube amps. This circuit was developed by applying the well known...
Nixie Tube Clock
A Burrough`s B-7971 Nixie Tube clock that I built back in 1979 when I was a senior in High School. The digits are 2 ½ inches high which allowed me to read the clock from anywhere in my bedroom without needing to wear my glasses. The clock circuit is based on a schematic that had been provided by the surplus parts vendor along
Using IRFP250 power tube H-bridge motor drive circuit
The drive circuit of electromotor includes a FET bridge circuit, FET base drive circuit,current sensor of motor drive circuit and the relay. FET bridge circuit mainly consists of four high-power MOSFET power tubes,it requires that the power tubes have good switching characteristics,can withstand higher drive current and have a long...
JFET Nixie Tube Driver
This is a driver circuit for nixie tube. This circuit uses 2N3684 as nixie tube drivers because its Vp is 2-5 volts which is ideally matches TTL-DTL logic..
High-Power Long-Life Compact Fluorescent Lamp / Tube lamp Controller
We can use UBA2021 for 600 V lamp controller and half-bridge driver IC for high-power. The UBA2021 is a long-life CFL/TL applications. It`s equipped with..
TPS65552A Xenon Tube Flash Driver
The size of the photoflash charger circuit is greatly simplified and reduced by Texas Instrument (TI) TPS65552A. A photoflash capacitor charger based on this..
12V 40Watts (2x20Watts) Fluorescent Tube Lamp Inverter
A 40 watt fluorescent (tube lamp, TL) or two 20-watt tubes in series will be driven by this circuit. The transformer is wound on a ferrite rod 10mm dia and 8cm..
12V 6-12 Watt Fluorescent Tube (Neon) Lamp Inverter
A 40 watt fluorescent tube lamp or two 20-watt tubes in series will be driven by this circuit but this circuit will produce less brightness than usual, since..
Valve phono preamp build
A stereo valve phono pre built for me by a techie mate. He has the power transformer and all components needed besides the valves which he advised me to source myself based on what would be most suitable to my needs. So, all you experienced DIYers, if you were building a valve phono pre for yourself, what configuration (push pull, single ended)...
Altec 1566 vacuum tube mic preamp and direct box
V1 and V2 are 12AX7 dual triodes. Each half of V1 is wired as a Class A voltage amplifier in a configuration known as Common Cathode. By comparison, both halves of V2 are wired together in the Cathode Follower configuration for current gain. Don ’t freak dudes and dudettes! Tubes are real high impedance (Hi-Z) devices — just like a passive...
tube overdrive pedal
That circuit is similar in concept to the BK Butler/Tubeworks Tube Driver. Since there is only a 9v supply, the tubes operate in "starved plate" mode. Preamp tubes normally operate on 100v-300v. It`s similar to using a Variac on a tube amp. When there is only 9v on the anode the tube operates way outside its linear amplification range and is...
The 125 Vacuum Tube Pitch Theremin
The circuit uses AC mains voltage and otherhigh voltages that can cause injury or death. The 125 is a basic heterodyne configuration, in which the outputs of two similar radio-frequency Colpitts oscillators are fed to a mixer, producing their difference frequency as an audible tone. A popular vacuum tube, the dual-triode 12AU7 (or its European...
Vacuum State Electronics FVP5A tube preamp
This was one of those reviews where time and circumstances conspired to allow a dual-test. I made the first contacts with Vacuum State, and Allen was eager to oblige. Combine this with a planned trip to Brittany and it was obvious that Geoff too would have a listen to the FVP. Eventually I got tied up rebuilding part of the house we just bought, a
CD47 (Rodan) Nixie Tube Clock
Build a CD47 Nixie Clock. Power: approx. 100 Watts (some might say "Isn`t it over- engineered", but you`ll see at the end of that project, that it`s ok. Nixies will be switched off when nobody is around- this will keep them alive as long as possible. The sensors for the detection will be a ECM (microphone) and a radar sensor. As you can see...
Vacuum Tube Guitar and Bass Amplifier
Describes the history and operation of vacuum tubes as well as how they are used in guitar/bass amplifier circuits. Amplifier electrical and physical layout is then examined. The factors affecting amplifier sound are also described. Included in the appendices is useful data such as: resistor and capacitor codes, vacuum tube electrical data, wire g
Vacuum Tube Amplifier Pioneer SM-83 Restoration
After restoring my Fisher 400, I could not let my smart head and creative hands rest. So I have started to look for another tube gear to apply my newly acquired skills. There was plenty of stuff around, but importing from USA to European Union is quite prohibitive - around $200 - $250 only for shipment plus domestic VAT and customs. I am was very
Vacuum-tube or electronic voltmeters make use of some of the unique characteristics of electron tubes, and so are available in many types. They are available for measuring direct, rms, average or peak voltages. Of the many types available, only the simplest and possibly the most commonly used type for measuring rms values of alternating voltages...
Power Supply for Battery Valve Radios
Many later radios use four 7-pin valves and require a 90V HT supply at typically 12mA and a 1. 5V LT supply at 125mA or 250mA depending on the valves used. The original batteries are sadly no longer made. One possibility is to make up a 90V battery using ten PP3 batteries in series for the HT, and to use two D-cells in parallel for the LT. This...
Vacuum Tube Direct Interface
Requires that DC power be brought into the instrument, either through special cabling or an internal battery. Should not be done to collectible instruments if they didn`t come with onboard electronics. Conveniently implemented as a field effect transistor (FET) or bipolar junction transistor (BJT) follower, or perhaps an amplifier with modest...
7 Tube Stereo Output Amplifier
This is a 7 tube 20 watt amplifier that must be used in conjunction with a pre amplifier having volume an tone controls. For this, I recommend this 6 tube pre-amp. With this amplifier you may use 6BQ5 output tubes. A 5U4-G rectifier is used so that the power supply will have plenty of pep to run the amp. This amplifier is basically a Magnovox amp
Nine Tube Stereo Amplifier 1
If you want to omit this balance control, such as when using separate pots for the volume controls, see the balance control notes on the 7-tube output amplifier page. "Wes, I used the schematic posted on your site, and built this. modified slightly with separate bass and treble on each channel. also, I moved the location
Japanese Antique Vacuum Tube Radios
Tube mic Connecting the capsule 2
Connecting a condenser capsule to the grid of a tube amplifier, in order to build a tube mic. In this part we consider how to connect a capsule with two diaphragms in order to get a multi-pattern mic. First let`s examine the different pickup patterns available. There are three extremes: Omni, where the microphone hears sounds equally in all...
Tube mic Connecting the capsule 1
Even in the simplest of tube microphone circuits, there are different approaches to connecting the microphone capsule to the tube. Let`s use a single-sided microphone capsule as our starting point. The capsule behaves as a variable capacitor, changing its capacitance in response to changes in air pressure (i. e. sound). In order to generate a...
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Musical & Effects Circuits
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
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