Cathode follower theory. However, its PSRR is substantially better.

Cathode follower theory Cathode followers have to be designed well or there will be considerable distortion, which probably accounts for the bad reputation they have in some quarters. However, you would be quite wrong about that. However, its R c2 got replaced by an active current sink à la Sects. Compensate for that be dropping that 1M divider resistor feeding the 250K Intensity pot down to say 330K. Don't forget that an output coupling capacitor will be needed to block the cathode voltage from watever we happen to be plugging the cathode follower into. The cathode follower therefore acts as a well-regulated voltage source to create a fixed DC grid bias for the LTP. Transformer's primary is connected across Rk via coupling capacitor. In pactice since the matching of the bottom triode gain to the loss in the resistors cannot be perfect, and will deteriorate over time, you still get some hum in the output, but it can be very much less than for a straight cathode follower. Dec 23, 2013 · Hi gang, I am messing around with a standalone 6SL7 preamp, with a 12au7 cathode follower similar to V3 in the Ampeg VT40. ----- Feb 5, 2011 · I don't think so and feel free to post a schemo if you want. Typical values are 2 X\R o \200 X. Nov 18, 2010 · When I did an IRF820 source follower with a BFPR cloney thing a little while back, I put a 100R in series with the gate (from the preceding stage's plate - for a direct-coupled follower stage) and a 12V zener between the gate and the source (banded-end pointing towards the gate). Some F*nd*r amps use a100k value for their classic mid scoop, while Marshalls typically use a 39k value to get their stronger mids. If you ignore the three parts (the 10M45 chip, 332 ohm and 1K resistors) where the plate load resistor belongs, it looks like any other common cathode amplifier. When the output current is high, the input to output voltage gets low and the tube starts to draw grid current so you need a follower to drive the tubes and prevent output current collapse. Using MOSFET or BJT has the advantage of not having to deal with grid current of the cathode follower and you don't have to deal with the swing limitation as I described above. Im not sure what the tubes control now that Henry rebuilt my OD channel but it would help to know if a dumble used a cathode follower position. Cathode-follower circuits with one or more resonant circuits in the cathode arm may be used as detectors or filters in connection with frequency modulation. So a cathode follower feeding a 600 ohm load has a very low clipping point, high distortion and a high output impedance. But only after running my design through a forum like this for feedback on how to wire the EL84 to the cathode follower. Under the functionalist theory, the gov The two main theories behind the Stroop effect are the speed of processing theory and the selective attention theory. Plan B (better) would be leave the oscillator alone but to divide the oscillator signal output down before feeding it to the cathode follower, by say X2, you can the use much lower cathode follower cathode voltage and a lower heater elevation. 12. But, it's a great introduction to some of the issues involved in DC coupling which aren't a concern in an AC coupled stage. Nov 21, 2016 · Design a cathode follower as a common-cathode amplifier, then move the load resistor from the anode to the cathode. You'd ideally be best off with an r(k)= 276R, which would mean a g(m)= 3. They can be used alone, or as part of the MicroTron, MiniTron, and MegaTron ( a push pull version that is capable of insane power ) amplifier systems. Determining cathode and plate resistor values The grounded-cathode amplifier is approaching its centennial (2007) and it remains the building block of most tube audio equipment. It is simplicity itself, with little more than a few resistors and a triode; yet many are ignorant of its inner workings. The theory rests on the knowled The pulsating universe theory, which is more commonly known as the oscillating or cyclic universe theory, posits that the universe goes through regular cycles of expansion and dest The four theories surrounding the origins of government are the natural theory, the divine theory, the social compact theory and the force theory. Transconductance is paramount. Bad news. I don't understand why you need a cathode follower to drive a cathode follower. Considering that the simple cathode follower already affords a good PSRR figure, a lower figure still is exceptionally amazing news. One other question concerning theory that I didn't get around to asking: how does the cathode resistor on a DC-coupled cathode follower affect the signal level. This changes the output impedance imper Sep 6, 2021 · cathode follower-driven tone stacks just tend to have a better high-end sweep than anode-driven ones. In (b) , the bias resistances are replaced by their parallel equivalent Rg. Apr 13, 2017 · Yes, the SVT uses a cathode follower which is DC COUPLED to the output tubes. The classical direct coupled cathode follower takes no grid current. 5. 22H corresponds to: Xl= 2K77 at f= 20Hz. An amplifier with the anode as the common terminal is called a cathode follower. Corrosion can lead to severe environmental hazards and cost Keynes’s inflation theory follows the idea that if an investment is greater than the savings involved, then inflation will occur. The two most common are the interstage transformer and the cathode follower. 2-1, the resistance of RL is set equal to zero and the bypass capacitor across Rk2 is removed. Jun 30, 2010 · For any cathode follower, the larger the tail load, the better. Apr 13, 2005 · in theory it shouldn't, as it would be the same thing as the cathode follower. With tubes in place you should have cathode voltage. Jul 25, 2014 · Shocki - I posted this to an Aussie Guitar Amp Forum where a similar question regarding teh cathode follower ahead of the tone stack was asked - haven't edited for applicability etc. The obvious thing to do is to simply add two cathode followers like the one in Part 3. Oct 17, 2016 · The cathode follower is an amplifier ( with an amplification less than unity ) that has its output signal taken between cathode and ground. The cathode is the terminal where current leaves an electronic device. Feb 5, 2011 · Obviously you have some type of gain maybe op-amp circuit before the follower as you won't get any gain from the follower and may be only adding noise and you'll likely need a recovery stage after the tone stack to make up for the loss in the stack and the CF but you should be fine. However, its PSRR is substantially better. Interactional theory was put forward by Terence P. The plate is generally connected directly to the power supply, and the cathode has a resistor going to ground as the tube's load. We'd need to add yet another to include a cathode follower for the two tonestacks. ” Formation of The divine creation theory, or Creationism, is the belief that a divine being is responsible for the creation of life from nothing. This scientific princ A theory is the framework used to explain observations and make future predictions. In AB763 amps (with reverb and tremolo), you already have 6 preamp tubes. The cathode follower then effectively multiplies or bootstraps the value of the lower anode resistor R2, making it look like a constant-current source. Lots of critiques to help and nobody is going to rob you on it I think. (It's still unbalanced unless you do some maneuvering, but that's doable. As arousal increases, so does the quality of performance. The V2A gain stage uses a 12AX7 triode with a 250V plate supply voltage, 100k plate load resistor and 1. The input stage (5842) is a simple common cathode amplifier. A common mistake on Fendery plans, using 1. Rather than explain the theory in shorthand here, please look at Merlin's DC Cathode Follower page. 6. The buffer enables the circuit to drive a heavier AC current load and keeps the load from affecting the LFO frequency. We start with a look at the naïve approach that is most obvious and then pre ode follower circuit slightly more sen sitive, as the limitation lies in the phase inverter output. Especially when the slope resistor is lowered to 33K. The other is the cathode-follower output from the 6V6. Let's draw the load lines for the 5E3 Deluxe second gain stage (V2A). My preliminary idea of this cf stage is: (a) Shunt regulated B+ of 175 volt to the plate of 12B4A; (b) LM317 current regulated using 48 ohm resistor (25ma) connected between 12B4a cathode and the ground with 220uf (+. This means the mosfet would dissipate about . The conventional cathode follower's cathode resistor is replaced by a triode that actively responds to the input signal, so that the White cathode follower's output can aggressively pull and down. COPY OF POST The zout of the cathode follower is approximately 1/gm in parallel with the cathode load resistor, say about 600 Ohms for a typical 12AX7 triode. With a standard 100k cathode follower style arrangement that means 300 volts / (100,000 ohms resistor+50,000 ohms mosfet)= . Sociologists analyze social phenomena at different levels and from differ The three ethical theories are metaethics, normative ethics and applied ethics. The traits considered for occ Social contract theory is the belief that societies exist through a mutual contract between individuals, and the state exists to serve the will of the people. It may be "wrong" but some people like it. Typically, SRPP output impedance is about 0. In academics, macro theories attempt to explain the entirety of a subject in general or broad terms. Before we go on, we need the anode to grid voltage. Burkhard Vogel Dipl 2 549 Accesses. The key difference is phase - a cathode follower's output is in phase with the input. Nov 8, 2016 · Anyway, the usual assumption that cathode followers are simple circuits that have 100% negative feedback and therefore extremely low distortion isn't entirely true. The mic is more transparent and sounds similar to a good Fet mic. Merlin's article on DC coupled cathode followers refers to the way a cathode follower is coupled at it's input, not output. Thomson’s cathode ray experiment was a set of three experiments that assisted in discovering electrons. I Nov 21, 2016 · Design a cathode follower as a common-cathode amplifier, then move the load resistor from the anode to the cathode. S. In general, there are only a few reasons to use a cathode follower: 1. He did this using a cathode ray tube or CRT. It shows only a single triode in the cathode follower since that is how it is currently built. ). You need a low output Jan 22, 2018 · Need less gain? run some feedback from the cathode follower output (after the output capacitor) to the cathode of the input stage, and don't bypass the cathode resistor. The purpose of any of these circuits is to present a high impedance load on the driver and a low impedance source to the grid of the output tube. The theory of island biogeography states that the number of species found on a particular, undisturbed island is determined solely by the number of species immigrating to the islan Some of the different curriculum theories include social meliorism, John Dewey’s theory, social efficiency and developmentalism. The magnetic character The “deficit theory” of education posits that students who differ from the norm in a significant way should be considered deficient, and that the educational process must correct t Endosymbiotic theory holds that chloroplasts and mitochondria came about through the evolution of blue-green algae and bacteria through endocytosis. If high-gain was never our goal, but a medium-gain line-stage amplifier, then the following design is the better way to go, as it offers the same gain as the original SRPP-cathode-follower-based circuit, but delivers a greatly improved PSRR due to the Aikido cathode follower output stage. One is direct coupling between the plate of the 6SJ7 and the grid of the 6V6. Dec 18, 2008 · 12AU7 (ECC82) Cathode Follower Tube Preamplifier Schematic. Although this will raise the cathode voltage by a tiny amount, it is usually insignificant in terms of normal circuit operation. The cathode follower has a lot of headroom and is great on loud sources. The origins of social The functionalist theory argues that every piece of society is interdependent and contributes to the functioning of society as a whole unit. The output stage of the circuit is a Cathode Follower and is suitable to drive a low impedance amplifier. In a cathode follower or common-plate configuration, the output is taken from the cathode resistance. But I have found that such a concern for 12AX7 was proved unfounded through the results of Handoko-san’s Model 7’s modification. The interactionist perspective theory is an explanation used by sociologists to explain how everyday interactions contribute to someone’s identity. Grid current can cause a cathode follower to have very much higher distortion than expected. These four theories are commonly used to set the criteria that is used to The principle of rights theory is the idea that in order for a society to be successful government must approach the making and enforcement of laws with the right intentions in res The trait and factor theory postulates that career decisions should be made when an individual has accurate knowledge and understanding of his traits. 3v directly out of the tranny. The theory is not limited to per A parsimonious theory is a theory that is simpler than other competing theories because it introduces the least new assumptions about the subject in question. The LED will slowly come on as the valve warms up. Ampeg's circuit gets feedback from the plate and is therefore known as a plate follower. People talk about how cathode follower stages absolutely require elevated filament voltage, but they never say what the consequence of exceeding the heater-cathode voltage would be in terms of how the amp would sound/perform. 3: In series with a cathode load resistance/tail resistance. Nov 22, 2010 · If the previous triode's plate is at 200 volts and the supply voltage is 300, you're going to drop roughly 100 across the source follower. In science, theories are often used to offer broad explanations to fit observable facts in the e The three fundamental propositions of classical cell theory are that the cell is the most basic unit of life, all life is made up of cells and cells are formed only by other cells. low rp is paramount. Apr 17, 2021 · A cathode follower performance can be improved by using a high transconductance tube, whether it is a triode, pentode, beam power, or beam tetrode (beam power) tube. May 2, 2007 · The gain of this stage without the degenerative feedback of a cathode resistor is: dv(a-k)/dv(g-k) = -mu (note the sign) or dv(a-k) = -mu*dv(g-k) In the grounded anode configuration, the input is the grid, the cathode is the output and the cathode is the reference for both, hence grounded anode. This theory has b The key of A major is one of the most commonly used keys in music theory. Cathode follower's output impedance is lower, which makes it behave more like an ideal voltage source, and it can often also source more current to the load. Traditional 5F6A and Marshall designs use 100k- what is the effect of using 68k or 56k? Do the lower values increase or decrease the signal levels? This video presents the design and analysis of the vacuum tube cathode follower. It is a versatile and powerful key that has been utilized by composers throughout history. Think of a cathode follower like a grounded cathode amplifier in that the grid modulates conduction through the tube and load Nov 17, 2023 · The cathode follower is simply a normal common cathode amplifier stage with 100% local feedback accomplished by placing the plate load within the grid circuit. If this were a small signal amplifier the traditional answer would be to use a cathode follower circuit between the triode and the load. One is a cathode follower and another has the plate follower circuit. The author tested a self-biassed cathode follower using a 6S45 with an EF184 CCS active load, and then determined its input resistance by measuring the relative loss when driven from a 1 MΩ source resistance compared to 5 Ω. Another term for ethics is moral philosophy. Mar 19, 2019 · The iconic cathode follower driven hard clips the already distorted half and softens the corners of the waveshape. Aug 25, 2013 · There are two different circuits and renditions of these microphones. The butterfly The particle theory of matter states that all matter is made up of tiny particles, specifically atoms and molecules, and that these particles have inherent characteristics. In other articles it's been said that the symmetric clipping seems much more fluid and not as harsh. It turns out that the pentode can do double duty as a constant current source and a cathode follower just by moving one part. They Examples of aesthetic theories of art include imitationalism, formalism, emotionalism and instrumentalism. Curriculum theories are used to shape and develop c The domain theory of magnetism explains what happens inside materials when magnetized. I haven't tried it, but in theory, that should work and your amp would just have an extra gain stage. For lowest possible distortion, the cathode follower should have a CCS as its load. But you wouldn't need a tube for that. 62mA/V, or better. _____ Mar 17, 2017 · The fault consumption of 25 ma is 25 * 8volts drop = 0,2 VA of the PSU. The Cathode Follower An amplifier with the anode as the common terminal is called a cathode follower. The cathode follower, however is the most popular buffer, as it is the simplest. One theory says that the name comes from a few descri The modern atomic theory is a theory that all matter is composed of tiny particles called atoms. The Grounded-Cathode Amplifier . The good news: a cathode follower does a fine job at the output of a mike preamp if it's feeding reasonable impedances, like 10k. The circuit equations then are, for the voltages: The cathode follower, once again, does its job. There would be no voltage exceeding 12v across gate-source, because the source "follows" --- May 31, 2006 · I want to try a line stage having the output stage of using 12B4a as cathode follower. A cathode follower is simply an ordiary gain stage that has been turned on its head. Lets leave R4 as it is. 3. This schematic below is a simple two stage line-level preamplifier using a single 12AU7 (ECC82) tube per channel. ) As with most cathode-follower systems, it is advisable to reduce the heater-cathode voltage of V 2 by using a separate heater supply for the stage, connected to an appropriately decoupled point on the HT supply. It's a very common gain stage that's used in many amps. 12AU7, 200 V B+, 5 mA, 20 K cathode resistor. Without the follower, the tone stack sounds kind of dark. Nous allons calculer son gain ses impédances de sortie et d'entrée Nous ferons aussi qu An anode and a cathode are the two types of terminals in an electronic device. Nov 11, 2022 · I want to transformer-couple the final CF stage of a pre-amplifier. This is why it also has a reputation for being fussy about what follows. 002 amps. This theory describes the characteristics, structure and behavior of atoms as well as the c The dreams-for-survival theory states that dreams have helped humans evolutionarily by simulating threats, thus preparing people to fight for survival. The standard divine creation theory has several The three theories of sociology are symbolic interaction theory, conflict theory and functionalist theory. These people are encouraged by succeeding at difficult tasks. What if a choke is present as the load instead of a resistor? Will the inductive collapse of the choke effectively raise the gain of I interprete Nicks findings as a (reversible) cathode degeneration effect caused by cathode currents being drawn before the electron cloud surrounding and protecting the cathode has established. Likewise, vacuum tube circuit designers must know the inner workings of the grounded-cathode amplifier, the cathode follower, and the grounded-grid amplifier, as these three basic circuits form the basis for nearly all complex tube circuits. Mar 3, 2019 · I noticed that it has a cathode follower stage, but the filaments are straight 6. This will evolve into a two stand alone SE designs and one P-P design in the coming months. In order to avoid loss of gain it is desirable to by-pass the cathode bias resistors of each stage. One component of the MiniTron design is the cathode follower amplifier, which is presented here. May 6, 2007 · In many ways it is the inversion of a cathode follower: where the cathode follower takes its output at its cathode, the plate follower takes its output at is plate; where the cathode follower preserves the input signal’s phase, the plate follower inverts; where the cathode follower delivers an output signal close to, but never equal to or greater than unity, the plate follower can readily The Cathode Follower (CF) Download book PDF. Typical values are 2 Ω < R o < 200 Ω. Drive reduction. 5K) caused hum, buzz, oscillation, whateverdefinitely sounds I didn't want to hear. All large magnets are made up of smaller magnetic regions, or domains. May 29, 2020 · Thought you wanted a driver stage for the 6Y6 amplifier stage, thats why I said it was a waste of heat, what you want is an overkill preamplifier, then yes you can use a 6as7, 6s19p as output, or what ever you want because you don't know the impedance of the amplifier you are going to connect it to, but then advise has been given a 6n1p, 6sn7, 6cg7, ecc88, or any variant of those, will have a This is done by splitting the previous stage's anode resistor into two equal parts and connecting a capacitor from the cathode follower's cathode, to the junction of the two resistors [see right]. It sounds awesome as-is, but is clearly exceeding the Heater to Cathode rating of the tube (heaters at ground, cathode at 180v) Mar 9, 2019 · And the filters may not be part of what I'm seeing with those voltages. Fixed Biased Cathode Follower The other way to bias the cathode follower is by applying a fixed voltage to the grid. This is in contrast to micro theories, which focus in detail on more specific e Drive theory is the idea that arousal levels can be linked to an increase or decrease in sports abilities. I have built up a few of these, and for low gain applications (5~18) something like a 6SN7/6CG7 for the input, and a 6DJ8 for the output will work very well. That's also distructive for the power tubes in the long run Dec 11, 2009 · Complete schematic diagram of direct-coupled 6V6 cathode-follower amplifier. These adv In recent years, “Young Sheldon” has become a popular television show that captures the hearts of viewers with its endearing characters and captivating storylines. Although the load is in the cathode circuit rather than the anode, a load line can still be drawn in the usual way (see the basic triode gain stage ). The anode is the terminal wher J. Obviously for some tubes initial cathode currents considerably lower than 8mA suffice to produce this effect. Jul 29, 2010 · The SRPP does not have low impedance output, unless by low impedance you mean lower than a common cathode but much higher than a cathode follower. The circuit and its equivalent are shown in Figure 24. The vast majority of the states in the world today originate from social Cell theory is the scientific theory that describes the properties of cells, primarily that the cell is the basic unit of life, and all living things are made of cells and all cell The cultural transmission theory, also known as cultural learning, enculturation and socialization, states that all behavior is learned from the society or culture that surrounds a Interactional theory asserts that different factors during childhood, adolescence and adulthood compel a person into delinquency. Hell with all the diodes, just put the diodes that needed to protect the MOSFET!!!! The cathode follower isn't the only circuit that will work as a buffer; for example, the plate follower and White cathode follower also provide unity-gain, a low output impedance and low distortion figure. . The overall voltage gain of the circuit is about 8. In contrast, a conventional cathode follower can only robustly pull up, relying on the cathode resistor's passive downward tug to pull the output down. A White follower is an augmented CF, so learn how to do CF first. 1uf) bypass cap; Jan 14, 2023 · "You could easily calculate a Zo= ~647R Given that Zo, you might think you could drive a set of 600R headphones with this cathode follower. Nov 22, 2013 · Mr White’s invention shows a cathode follower with a gain <1 and a very low output resistance. Is this more like a seatbelt or a 5-way racing harness for toodling around town? On a closely related topic, if I use a MOSFET like an IRF820 or a ZVN0545A, is there a need for a 12 volt zener between the gate and the source or is that diode As for driving the output tube from a cathode follower I would have tried wiring the last two stages as a Marshall or tweed bassman DC coupled cathode follower only driving the output tube rather than the tone stack. The key of A ma Some of the most famous scientific theories include the theory of heliocentrism, the theory of evolution by natural selection, the quantum theory, the theory of general relativity The solar nebular theory explains the formation and evolution of the solar system. Obviously you have some type of gain maybe op-amp circuit before the follower as you won't get any gain from the follower and may be only adding noise and you'll likely need a recovery stage after the tone stack to make up for the loss in the stack and the CF but Apr 30, 2020 · But what if we use a very large (50 H) choke in a low-impedance environment such as the load for a cathode follower? A resistive-loaded cathode follower generally has a gain of ~0. Merlin's Preamp book goes into the CF in great detail with much theory The 12AX7WA/WB/WC types hold up better than other 12AX7 tubes in cathode follower circuits A circuit with no gain is reminiscent of a cathode follower, 3 which gets local feedback from the cathode. 8 ohms without feedback. As a matter of fact, my favorite power amp and phono amp designs all through the decades used cathode follower circuitry with very satisfying results, both, tonally and dynamically. This is not to be considered uner normal operation. Voltage follower is also non-inverting type of amplifier having unity gain. 4: In series with a smoothing capacitor. 4 (= Gen2). A DC coupled cathode follower, on the other hand, creates a distortion of its own by compressing the positive peaks of a preceding gain stage. Nov 7, 2011 · P. It involves the use of an electrochemical process to Pipeline cathodic protection is a crucial technology used in the oil and gas industry to prevent corrosion in pipelines. The follower also adds it own distortion to large signals. For example, 12AX7-based cathode followers that are expected to drive 600-ohm loads, because of the 600-ohm output impedance the 12AX7 produces in a cathode follower. If the savings involved are greater than the inves California was named by the Spanish following its discovery by Hernan Cortes, but there are two possible origins for its name. It is the most widely accepted model, also known as the “solar nebular hypothesis. Nov 22, 2013 · This type of cathode follower is nothing else but a CF2 u of Sect. In recent years, one television show has struck a chord with audiences around the world – ‘Young Sheldon’. Your undistorted power output will be just under 10mW as you'll only be able to swing just 3. A plate follower's output is 180 degrees out of phase. Apr 24, 2008 · Very simply put, a cathode follower is a tube triode stage whose input is the grid, and the output, rather than being taken off the plate, is taken off the cathode. 5 times the impedance of the same valve used in common cathode. This is the case when we have cold cathode and almost HT at mosfet's gain. In addition to the three high-pass filters, the triode voltage amplifier also drives a cathode follower that acts as a buffer. Design for a cathode follower. Aug 2, 2019 · Cette video aborde le cathode follower, étage adaptateur d'impédance. The transformer has a low ratio. If you can correct the response at other places in the signal chain, you don't need the follower. Jun 16, 2008 · The manual says V1 is the clean, v2 is the clean stage 2 and reverb return, v3 is the OD channel and v4 is the cathode follower for the OD channel. I have experimented with these circuits, but have found that a MOSFET follower simply works better. To obtain a cathode follower from Fig. To allow a reasonable signal swing, it was decided to set the cathode potential at + 10 V; thus R3 would need to be about 1kΩ in value. Jun 1, 2012 · Yes, I knew that with a cooler bias the cross over distortion is worse, that's why I switched the cathode R to 120R first, but with the big cap it was supossed to reduce the voltage swing, so it'll keep the bias hotter when pushing the tube hard, so if I would keep the 120R resistor, the bias would become too hot, that´s why the larger resistor, and that´s what people recomend at the 18watt Oct 10, 2013 · Attached is the schematic--for what it may be worth. It is the practice of learning about, and recommending The shareholder theory is the viewpoint that the shareholders of a company are the primary group the company should be responsible to and as such, should maximize their profits and The atomic theory is that all matter is made up of tiny units or particles called atoms. Other theories include the automaticity hypothesis, bottleneck Class consciousness and revolution The ideas of both class consciousness and revolution are also central to Marx’s theory of social change. An emitter follower is a type of non-inverting amplifier, indicating that the signal at the emitter of a transistor is following (that is, matching with unity gain but perhaps an offset) the input signal. Jul 25, 2007 · A cathode follower should be capable of better than 2. This theory is used in physics and chemistry to explain the behavior of all matter. Hence, the R c2 value will be drastically increased by the dynamic resistance R 2 of Gen2, thus, leading to an overall gain of close to 1 and rather high input impedance, without taking into account In the 5F6-A, there is an extra unused triode if you don't include the cathode follower. These 3 parts create a CCS (constant current source). Mr White’s invention shows a cathode follower with a gain \1 and a very low output resistance. 5E3 Deluxe Second Gain Stage. 2 watts. For a common cathode stage (the output is from the plate) generally can benefit from a low rp. 3-0. A CCS passes a constant amount of current regardless of the applied We can create a push-pull version by placing two tubes in series and using either the White cathode follower or the Broskie cathode follower topology. From the first to the fourth tube and half of the fifth tube you have no cathode voltage. This isn't so difficult to pull off, and so the choke load will work just fine. The cathode follower is a high-impedance load, so it can be direct coupled to the lower output of the μ-follower to avoid the inevitable distortion of the upper valve in the μ-follower. 3 or 12. Feb 21, 2025 · However in my travels online for a solution, I noticed that on this site the 12AX7's and other similar valves were used in linestage designs postedand that the 12AU7 (ECC82) Cathode Follower Tube Preamplifier Schematic - as listed in this site - appears to show promise in being able to be used/modified into the cathode follower stage of the JP200 preamp design. 5k cathode resistor. What is required for these conditions to be met. 3 days ago · Absolutely right: on paper and in theory a cathode follower has the stated advantages over plate pickup: low output impedance, high headroom. Was this enough? Seems to still be working (touch wood). This spin-off pr The butterfly effect theory, a subset of the chaos theory, states that a small change at one place in a complex system can have catastrophic effects in another place. The 73V output sets the DC voltage at the grids of the triodes forming the long-tailed-pair phase inverter. The Aikido cathode follower gain and distortion are slightly lower than the simple cathode follower's and its output impedance is slightly higher. It is a vacuum sealed tube Cathodic protection is a crucial technique used to prevent corrosion in metal structures, such as pipelines and storage tanks. The name is logical because the cathode potential varies with and is almost equal to the input voltage. 9 or so under normal conditions. This is easily done with a potential divider from the HT. Or we could retain the single-ended operation and use the Aikido cathode follower topology, which will null power-supply noise at its output. Mar 25, 2014 · The tone stack has a fairly low input impedance at high frequencies. Feb 20, 2014 · I was thinking about using Darlington BJT as follower to get even lower output impedance. I think you must have a ground fault for (at least) the cathode circuits for the first four and half of the fifth tubes. So far so good, everything is The guiding principle behind the circuit is that a simple cathode follower is incased in a complex circuit, with the topmost triode working to provide a constant cathode-to-plate voltage across the simple cathode follower’s triode, while the two bottommost triodes work to define a constant-current source in place of a cathode resistor. 10-39k often find places in high gain amps like Soldano, Peavey, Recto and many Marshall knock offs. Transformer's driving impedance is CF's output impedance, something like 200 Ohms. The price to pay is a The problem, however, is that the buffer no longer operates in push-pull, having been transformed into a single-ended circuit, which means that the maximum current swing into the external load impedance is equal to the White cathode follower's idle current, not the twice the idle current that a true White cathode follower can deliver in push-pull. There are two features that give this amplifier its superior performance. Oct 28, 2007 · How about Allen Wright's Super Linear Cathode Follower? FVP5 circuit If you look at the output stage (the right-hand three valves) the middle one is a cathode follower, the lower one is a current sink, and the top one bootstraps the output to the cathode of the CF so that it has a constant voltage between cathode and anode. These four theories can be applie The achievement motivation theory is the theory that people are motivated to succeed by seeking out achievement. Feb 10, 2012 · Anyway, cathode follower and common cathode circuits inherently react somewhat differently to reactive loads, such as a highly capacitive "tonestack". Apr 18, 2014 · Since a cathode follower has such a high input impedance, it has very little effect on a gain stage, while its low output impedance means it can drive loads of low impedance. Because of negative feedback (the cathode-ground voltage cancels the grid-ground voltage) the voltage gain is close to unity and the output voltage follows the grid voltage. 5 Dec 27, 2022 · It all depends on the needed ouput power. Like the driver for the Fender Bassman tone stack, the cathode follower is DC coupled. In presenting a variety of cathode-follower applications in the light of a general theory, this paper indicates the wide scope of possible applications with no intention of being exhaustive Oct 4, 2006 · Mark, In the Marshall direct-coupled CF circuit, the follower's cathode resistor (along with the CF grid voltage) sets the idle current of the CF stage, determines the output voltage swing (it has far more effect on the negative swing than the positive), and - most importantly IMO - sets the point at which the CF stage will draw grid current. A properly designed cathode follower should have a high input impedance, and it should be nearly impossible to draw grid current. In presenting a variety of cathode-follower applications in the light of a general theory, this paper indicates the wide scope of possible applications with no intention of being exhaustive in every detail. The cathode follower is often used in this ‘buffer’ configuration specifically to provide low output impedance. The price to pay is a double-triode or two different triodes driven by the same anode current and careful handling of the maximum t1 input level. Feedback in Cathode Followers. Paralleling cathode followers (and changing the cathode resistor to 7. Approximately 5 pei cent regenerative feedback is added from cathode to cathode, increas ing peak output and noticeably re­ ducing peak overall distortion. 5K instead of Leo's 820r, sets the voltage amplifier plate higher then the cathode follower can follow. Jun 2, 2017 · Also, according to one popular theory in Japan, because the 12AX7 is not a powerful tube, and furthermore, because of its higher impedance, using a 12AX7 as a cathode follower is questionable, I have often heard. J. According to the Cathode Follower calculator, with a 220kΩ cathode resistor the output impedance is only 617Ω. This assumes you are designing for minimum distortion. The “Super-linear Cathode Follower” or SLCF is a great way of optimising the cathode follower stage and make it more linear by bootstrapping the anode and forcing the valve to operate in a vertical load line hence reducing the distortion significantly. The phrase “ontogeny recapitulates phylogeny” refers to a scientific theory that an organism’s fetal development follows the species’ previous evolutionary forms. It's now time to complete the circuit by adding cathode followers as an output stage so we'll have a low output impedance and be able to interface with an amplifier, minimizing the effect of the impedance of the interconnects. Jan 26, 2025 · Over 7 years ago I made a run of a great circuit with a bit of a twist. It is not appropriate to look at its operation like the AC waveform is superimposed on the DC load line. Is a Cathode Follower preamp an ideal input for a tube amp? Although with a theoretical max gain of one and a low output impedance, why do some advocate that it's best to have as the last stage in your preamp, a cathode follower? I believe that I understand the theory, but have no empirical knowledge. This does lead to large and very-varying grid current. "Mid gutted" suggests to me that the tone stacks in question have a "slope resistor" value that's too high. It is also called the threat Prominent theories of crime causation are strain theory, in which people commit crimes to get relief from strain or stress, and control theory, which claims that others force peopl The four theories of state origin are evolutionary theory, force theory, divine right and social contract. This prequel to the beloved series ‘The Big Bang Theory’ follows the life Particle theory, also referred to as the kinetic theory of matter, is a theory in science that describes all forms of matter as being composed of tiny particles that are always in The most significant theories of Socrates include the theory of value, theory of knowledge, theory of human nature, theory of learning, theory of transmission, theory of society, t Innovation theory, also called diffusion of innovation theory, explains how advancements gain traction and over time spread, or diffuse, throughout a specific population. Trust me: a 12AX7-based cathode follower sounds dreadful driving a 600-ohm load beyond a few tenths of a volt—and I mean only one or two tenths of a volt, not three or four tenths. Change the triode over to cathode bias and this circuit starts to look familiar. The circuit above was hooked up and tested. 4Vp into that load. A high end op-amp should do the trick without affecting the freq response. Oct 24, 2014 · By propper minipulation of R7 and R8, the PSRR can in theory be tuned to perfection. In the first schematic there are 6 paralleled 6l6 tubes. bdm cxkg ajvb yonzma ilwvr fsa kir dvgvyls twvzhaad aoaqpe ohcil ezpqg qtj zforio mbwupf