Cathodyne phase inverter. C4 – Gain stage +DC-coupled cathode follower.

• Cathodyne phase inverter The problem is that the second amplifier has an amplitude that is larger by a factor equal to its gain. Bucks '68 : 50W British two Designing Tube Preamps for Guitar and Bass is the most comprehensive guide to the design of tube-based preamplifiers for musical instrument use, in a single volume. Fullerton '57 : Single input class A output stage produced from '57 to '60. These are widely used in the music instrument & Back to the Phase Inverter. But it differs from the Deluxe in subtle, yet important ways. You save one tube using a cathodyne phase inverter versus a Long Tail Pair phase inverter. We will show that by changing just one > paul c mod (Cathodyne Phase Inverter Fixed Bias) << Prev Topic | Next Topic >> Author Comment bluesrx Junior tube assistant Posts: 7 (1/1/04 11:16 pm) 65. In V2, with a standard ECC83 in V1, it has a really nice classic rock tone, but it loses its punch - you must run an overdrive pedal to get it cooking. co. I was hoping replacing the 12at7 would give a little beef. Re: Any examples Electronics: Headroom of cathodyne phase inverter (in vacuum tube amplifier)Helpful? Please support me on Patreon: https://www. A curious thing, its outside of the global feedback loop and it does not appear to have any local feedback. Hard to see in the picture but the bias was set so hot (around 90%) that the solder on pin 432 Fig. Posts; Latest Activity; Photos . Joined 2013. As it stands I was pondering a 6SN7 as input/phase inverter (Long tailed pair) feeding a 6SN7 driving each half of the push pull outputs. The PT really calls for a voltage doubler and that hasn't been unreasonable to work with. While that's true, in many amps (like the 5E3, for example), the cathodyne is one triode in a twin triode bottle, usually a 12AX7. Also, for the driver stage ahead of the phase inverter, use a 100k plate load and the same 2. The coupling capacitors CG block the high DC voltage from the phase inverter while allowing the inverted and non-inverted audio signals to pass. Has trimpots for bias and for hum balance. The differential pair (long tailed pair) is a phase inverter with two inputs, which amplifies the voltage difference between the two. It sounds sterile-clean, just like a The 5e6 has a cathodyne phase inverter at least it appears so to me. P. This could be obtained from a cathodyne operating under a high B+ voltage but this is not always available. Investigating it, I found that the Is there any problem with using a 12AU7 or 12AT7 as a phase inverter? It seems that amp techs generally frown on using either in the preamp section. I can always make use of used tubes in my own amps. e. Jump to Latest R. What many nowadays call a cathodyne phase inverter is a split load PI also known as "concertina PI". It makes a pretty nice wide band amplifier. The signal also flows out V2B's cathode to a coupling cap and on to power tube cathodyne phase inverter described in chapter 7 is well suited to driving relatively sensitive power tubes to high levels of overdrive but if we wish to drive larger tubes to similar levels of distortion then we require large signal amplitudes. The main limitation of a cathodyne is the PP output signal swing is limited to around 1/4 to 1/3 of the HT supply node (for the cathodyne). It has been a while but I promised to report back my findings regarding the cathodyne phase inverter in my tweed Super. I changed the novar sockets for the 7868s (9-pin the size of an octal socket) to octal sockets for 7591s. Somehow added a deeper, tighter, more articulate low end. For that reason there is usually a gain stage just before the cathodyne. If that cathode is bypassed you would put a small value resistor between the cathode resistor and bypass cap and ground. V2A is DC coupled to a cathodyne phase inverter and then 4xEL34 in the output. As is generally well known however, the two outputs from a cathodyne type phase inverter are quite different in terms of the impedance they represent, with the output at the plate being much higher than that at the cathode. (which is the same as stock), and a 12au7 as the actual phase inverter. I. Without this connection, the first stage is a traditional voltage amplifier with a feedback insertion point at the cathode, just like the second stage of the Fender Champ 5E1, for example. Filter. Collapse. In a push-pull amp, the output tubes’ inputs arrive 180 degrees out of phase. DF96. Also, if we push a signal into the grid and we don’t have a . C8 – Cascode SRPP. The problem with using a 12AU7 is that the other triode in that tube is This brings us to the cathodyne (or split load) type phase inverter, which can be a decent phase inverter. Just a 12AX7 for V1 driving the tone stack and FAC selector then a 12Ax7 in V2. This The cathodyne phase inverter stage runs at a gain of just under one, so whatever is at the input you have the same signal size at the output. Should we try a paraphrase inverter? In this case we have the cathodyne phase inverter, which is one of the simplest. 1; 2; Next. and Rp. The Pro has 12ax7 on each channel + + second 12ax7 stage + 6SN7 phase inverter + EL34 output Somewhat similar sounding, but definitely different animals. 5k grid stoppers on the The triode section of the 6BL8 is being used as a split load ( or cathodyne ) phase inverter. C2 – Self-bias cathodyne phase inverter (also cathode follower) C5 – Fixed-bias cathodyne phase inverter. In modern times this circuit seems to have 3. Previous 1 2 template Next. i scored a nice `73 princeton reverb A single triode mounted as phase inverter, biased by a resistor bridge. uk/g8hqp/ 2011-05-05 11:03 am #2 2011-05-05 11:03 am That might make up for the gain you'd lose from a cathodyne and its less-than-unity phase-to-phase gain. This is my son's amp. 86 Reply | Edit | Del All paul c mod (Cathodyne Phase Inverter Fixed Bias)----- hi all looking for a layout for the paul c mod. FWIW, assuming you have adequate B+ voltage, you likely could make a long tailed phase inverter borrowing the same operating points -- 47k feeding each plate, 1k5 bias resistor, tail resistor to taste. Fullerton '61 : Two input long tail pair phase inverter and bias wiggle tremolo produced from '61 to '63. Like in the vibrochamp This is a very basic and easy to implement post phase inverter master volume that you can implement into a guitar amp that uses a push pull output tube confi Fender Princeton and Princeton Reverb amps have a split-phase phase inverter that has a gain of 1. Paraphase Phase Inverter: Phase Inverter comparisons 02-03-2010, 02:52 AM. I would also put The paraphase inverter is the oldest and conceptually simplest of all phase inverter circuits. 8 Any signal that is fed back from the cathode follower stage, or from the cathodyne stage, is less than the 80x signal from the plate of the input tube to the input tube grid. 047uF into 220k. 4. I liked the output and flexibility of the 12AU7/12BH7 tubes for the true push-pull power amp. One is the “Cathodyne”, also known as the “Split-Load” (Fig. What would be the advantages of using half of a 12AU7 as the triode for a cathodyne phase inverter as opposed to a 12AX7 (disregarding the fact the other triode would probably be the preceding gain stage with a lot less gain)? I see on the data sheet for this tube that it lists a grid resistance of 1Mohm (with Headroom of cathodyne phase inverter (in vacuum tube amplifier) Ask Question Asked 4 years, 7 months ago. Phase inverter distortion on a Princeton Reverb sounds Cathodyne phase splitters are better suited for lower drive tubes such as EL84s or 7591, etc as it has zero gain and lower voltage output. Modified 4 years, 7 months ago. C17 – Basic serial voltage regulator . So, the gain is 80 x 0. I would think I'm curious about the V3 which is the phase inverter if it needs to be have balanced triodes or can I just pop in any 12AX7. Search titles only By: Search Advanced search Search titles only Making a phase inverter using an interstage certainly cuts down the cost , parts count, and makes it simple. The mod creates a fixed bias on the phase inverter grid by creating a voltage Phase inverter distortion. Modern Picks. UUUGGGHHH!!!! With Strictly speaking a phase inverter is any circuit that produces two signals of equal amplitude and opposite phase. It is a simpler and less expensive design but may The Princeton Reverb uses a cathodyne phase inverter instead of the AB763's long tail pair (LTP). 179. Thread starter rifraf50; Start date 2016-10-02 6:40 am; Status Not open for further replies. Draw the Load Line Thus in amps that use a cathodyne PI such as the OR120 the other triode in the 'phase inverter' tube is used as another gain stage prior to the phase inverter. This is an inherent characteristic of the design, resulting from the cathode output taking the form of a cathode follower configuration, which by Each inverter has its own flavor, and plays with feed back in different ways. Viewed 573 times 0 \$\begingroup\$ I know that gain of cathodyne is almost 1, so if it's going to produce 12V peak output, it has to take 12V peak input. A phase splitter or phase inverter refers to the polarity of the current and is simply made by changing different kinds of amplifiers (or) optimizing a transformer to efficiently split currents. All Time Today Last Week Last Month. Whereas I do notice it on the coupling caps to the output tubes, eg, the vintage 0. 6 KB · Views: 368 Last edited: 2011-05-05 10:03 am. There's the option of adding a presence control at the same time. The . I have isolated the paraphrase from the signal chain The Paul C Mod changes the typical cathodyne phase inverter from cathode bias to fixed bias to offer more clean headroom and give a more balanced output. Thanks to Heikki for spotting this! In fig. To draw a cathodyne phase inverter's load lines we have to consider the tail load resistance and how the tail load resistor affects the cathode and grid voltages. The cathodyne phase inverter is a cross between a gain stage and a cathode follower, because the total load resistance is divided into two parts and shared between the anode and cathode. So you need another gain stage in front of the cathodyne. The phase inverter can use various circuits, and the gain of this position in the circuit can vary from less than 1 (split-load/cathodyne inverter by itself) to ~1/4 of Mu (long-tail pair, as used in most amps) to ~1/2 Mu However, technical info and design procedures on this type of phase inverter is scarce. Luigi RETRO-CUSTOM Amplification strives to make your life a little easier by offering PC Boards for your builds and repairs. The 200S pre-drive, phase inverter, and output topology are perfect for what I want to do except for 2 things: 5E3 Cathodyne phase inverter balancing. Let's say in a cathodyne you replace the plate resistor with a potentiometer, using a value matching the cathode resistor. 3. To quantify how this connection improves performance The cathodyne phase inverter's total differential gain is slightly less than 2. Cathodyne phase inverters are often used in smaller, low-power tube amplifiers. Closed, cathodyne plate connects to B+ and no audio signal to 1 output tube. The Japanese-made 12AU7/ECC82 that you have should work well. txt) or read online for free. Gain is always less than one. February 2015 edited February 2015 in Amps. Although not designed for that amp, even the ECC83 works fine as a phase splitter (to my ears the sound is better with the original ECC81). Adding a grid stop resistor at the input of the cathodyne phase inverter gets rid of the nastiness when the amp is cranked. Many of us consider that gain stage to be part of the phase inverter. The most commonly used phase splitter is a cathode The signal then flows to V2B, the cathodyne phase inverter where the guitar signal is split into two streams for the two power tubes. Gerald The rectifier is a voltage doubler, the bias supply is capacitor-coupled, there's a lone 7-pin triode as a cathodyne phase inverter and the choice of output tubes is unconventional. The other thing that I keep reading about in the LTP vs cathodyne discussion is that the LTP has more gain than the cathodyne. . Specifically, for the 5E7/5F4 circuit, would good results be expected with a 12AY7 in v1; a 12AX7 in v2; and a 12AT7 as the phase inverter? Leo went from a common used in radio splitter (paraphase) to a Cathodyne splitter (concertina) in the next incarnation of the Deluxe. To compensate, an attenuator can be added to its input to reduce the signal amplitude by the same amount. I found the ECC88 to work best as the driver tube & cathodyne phase inverter in a 6V6 Push Pull amp. In the 5E3 output stage design, using AX7 nominal plate curves, it looks to me like the phase inverter should operate very nearly Try Googling up "Long Tail Pair" or "Schmidt Phase Inverter", and you should come up with plenty of schematics. 1: Simplified cathodyne phase-inverter. 2013-11-15 7:15 am #22 2013-11-15 7:15 am #22 See the Radiotron Designer's Handbook 4th edition at the page The greatest weakness of the cathodyne PI is if driven too hard it can develop nasty double-frequency distortion. balanced input signal, which should mean exhibiting equal impedances, but cathodyne - Free download as PDF File (. From the input to the phase inverter this book discusses in detail the inner workings and practical design of every part of a conventional guitar preamp, including the use of triodes, pentodes, tone controls, effects This type of phase inverter always have gain less than 1. Page of 2. Plimpington2 Well-Known Member. There is a section on this in Merlin Blencowe's valve preamps for guitar book. 2016-10-02 6:40 am Then I gave up on the long tail PI and put a boot straped cathodyne PI and still it distorts with the same distortion. What is it and what are the I just acquired a pair of Dynaco Mk 3 chassis with power transformer and OPT, without the driver pcb. Is there a reason you're not considering a cathodyne over the LTPI to reduce gain? Top. 9 x 0. If you're willing to lose the tremolo, the tremolo tube stage can be used to build a long-tailed pair phase inverter. I've read many articles and watched many videos on the subject and they still leave me with the same thoughts/questions: Re: cathodyne phase inverter ? « Reply #7 on: March 10, 2012, 10:27:44 pm » Fyl I have normal master before the pi whats added is a master between pi and power tubes. 1 shows a simplified cathodyne, and it can be seen that an inverted Hoping to get some opinions and possibly start a discussion of the ins/out of the two main types of phase inverters, Cathodyne & Long Tailed Pair (LTP), we can ignore the Paraphase, for now. 12. However due to the design of this type of phase inverter the actual value of this gain is much less dependent on the type of tube used - that is, substituting a lower gain tube in place of a higher gain tube won't reduce the gain of a cathodyne phase inverter significantly. myweb. Go. The bias setting of -1 volt to -1. Directly comparing to the gain of a cathodyne PI (a little below 1) wouldn't be fair as this only Cathodyne phase inverter What's more, you can implement this with: AC coupling Level shifting Cathode bias Fixed bias Direct coupling with a grid-cathode protection diode! But wait, there's more! The tone stack can be connected either to the cathode or anode of V1b, or not used at all, and it can be configured either as: Traditional FMV tone stack James tone stack with mid shift! cathodyne phase-inverter. Unbalancing the signals to the output tubes can be done by tinkering the resistors is done in many amps using long tailed pair PIs. Fullerton '55 : Two input class AB output stage (with cathodyne phase inverter - no feedback) produced from '55 to '60. The above image has been linked from the Ozvalveamps website Adding Feedback & A Presence Control To A Gibson GA-8T (Cathodyne Phase Inverter model) Collapse. split load inverter: also known as P/K or "cathodyne" phase splitter. It had a whole chapter on phase inverters, which covered as bad things (for their purposes) what happens when the PI is unbalanced. The optional Headphone Jack can be full size 1/4" or the now more common 1/8". These cathodyne (Concertina) phase inverters can swing healthy current depending on the setup, so the tube can wear out with time. I've also heard and read from various sources that the LTP is better for driving larger power tubes. So I replaced the two 1. The signals on each grid are mixed, and balanced outputs are taken from the anodes. com where Merlin stated disbalanced paraphases creates more 2H Presented is the wave form produced by my modification to the phase inverter of a Fender 5E3 Tweed Deluxe guitar amplifier. Simp Cathodyne phase inverter? Gassage Frets: 31945 . 5 volt refers to the The cathode of the cathodyne phase inverter 1 is connected between the two resistors via a 4μF DC-blocking capacitor. 9 = 64. Next Last. By the design, it is well balanced with light loads. But first, let us do a quick recap on the circuit. That means it has the 12ax7 half as the stage preceding the P. Split-Load Phase Splitter "Taming the split-load inverter" and after designing my 6AS7/6080/6082 based OTL, it seemed to me that many more topological tricks remained latent within the humble but capable split-load phase splitter. The nice thing about a 1/8" jack is you won't mistake it for It has two gain stages followed by a cathodyne phase inverter driving a pair of 6V6 output tubes, and it uses the same size cabinet. Wonder who/where/when started this confusion. The Pro. In fact, the Greek word para means 'side by side', which neatly describes the way the circuit creates a new path in parallel with the original. I know it was common to use it in a paraphrase arrangement (the 6sc7), and with a single cathode it's not possible to do a cathodyne inverter, but has anyone seen one used in a long-tail pair arrangement? Seems possible to me since the ltp has the 2 cathodes tied Amps. 2013-12-05 7:45 pm #1 2013-12-05 7:45 pm #1 My "rockin" breadboard Deluxe phase inverter seems to be quite a bit unbalanced. The Schmidt Splitter/Long Tail Pair phase inverter had been around since the 1938, as an out My idea was having one feedback loop that controls the resonance circuit in the PI and another feedback loop in the PI that controls the Presence circuit as I don't have the know-how to integrate a resonance circuit into a cathodyne phase inverter without applying the feedback to the cathode resistor of the first stage. C15 – Differential phase inverter, long-tail pair, cathode bias . It can be thought of as being This video is all about exploring what happens when we intentionally throw a cathodyne phase inverter out of balance. It has been used in many popular guitar Chapter 12: The Cathodyne Phase Inverter The cathodyne* is the quintessential phase inverter –beautifully simple and absolutely balanced when used I've built a number of amps using both cathodyne (always with the Paul C mod) and long-tailed pair phase inverters, but I've never built two similar amps so that I could Cathodyne. Mainly the difference in the phase inverters. Let’s pause and reflect on what we know about valve amplification When a signal is pushed into the grid, the amplified signal coming out at the plate is inverted. D. position - if you find it an improvement we could look at a trade-in on your ECC803S (assuming it's the 803S version you've got). The other triode is usually configured as a normal gain stage in front of the cathodyne. Pros: Very simple; Performant when followed by a cathode follower before the A phase splitter or phase inverter refers to the polarity of the current and is simply made by changing different kinds of amplifiers (or) optimizing a transformer to efficiently split currents. 6P36S is easiest to use as a pentode connected, not UL, because it requires relatively low Ug2. Thought someone might be interested. If the PI circuit is like the typical LTP (Long Tail Phase Inverter) that Marshall and fender use, then it shouldn't be an issue. Member. new posts. Right now the Rebel can get some gnarly grind out of it when it's cranked. 5-times approach 1) the load resistance R L equals the output resistance R o. AS JM Fahey said, you need to drive the cathodyne with the same sized input signal that you want to get from each output. I think as long as theyre not used where usable gain is being made, they could be very useful, both cheap to obtain and last forever, as well as accurate reproduction of preceding stages. General. Chapter 12: The Cathodyne Phase Inverter The cathodyne * is the quintessential phase inverter –beautifully simple and Then I read Merlin Blencowe’s discussion of the cathodyne phase inverter, where he recommends larger grid stopper resistors on the output tubes. The circlotron is a push-pull output stage that requires a push-pull, i. Roe Posts: 1769 Joined: Thu May 31, 2007 2:10 pm. 1 shows a simplified cathodyne, and it can be seen that an inverted output is taken from the anode while a non-inverted output is taken from the cathode. There are two designs that dominate guitar amps. I think I saw a thread on 18watts. So according Merlin at Valve Wizard the Cathodyne PI WITH a preceding gain stage has more gain and better balance that the Long Tail Pair. This effect usually causes the ugly 'blatting' overdrive tones sometimes heard in amps using this kind of phase inverter. Joined 2015. This video describes the purpose and design of three different common phase inverter circuits: Split Load or Cathodyne, Paraphase, and Long-Tailed Pair. Williamson: cathodyne + differential amp (also known as a "long tailed pair) 6. 5 KOhms. A long-tailed pair usually has a little more output signal swing than a cathodyne using the same valves (but not as much as some 'techs' might suggest), and it has I restored a 60's lectrolab with cathodyne phase inverter and cathode bias el84 output and it sounds glorious, but I want that nasty old paraphrase, thanks for all your help, looks like a modified ampeg inverter and Placing the Master Volume before the phase inverter (PREPhase Inverter Master Volume) will allow you to control the amount of the 5E3's infamous phase inverter overdrive 'double frequency' distortion at high volume Cathodyne phase inverter What's more, you can implement this with: AC coupling Level shifting Cathode bias Fixed bias Direct coupling with a grid-cathode protection diode! But wait, there's more! The tone stack can be connected Cathodyne, LTP, or schmidt? It seems a lot of amps use cathodyne, I have seen some guitar amps that use Schmidt, which is very similar to the LTP Search. 12AU7 as cathodyne phase inverter 10-07-2013, 12:57 AM. The cathodyne phase inverter circuit in the Fender 5E3 Deluxe is used in many other amps. The extremely rare 1962–63 6G10 Harvard [5] used a single 12AX7, 6V6GT and 5Y3GT; [4] it was simply a way to use up leftover 50's Princeton (5F2-A) chassis and tweed cabinets, after Fender had re I call a stage between phase inverter and output tubes as "driver stage". X. The first half is a plain old gain stage, the second half does the PI work all by itself. The signal enters at V2B's grid and flows out its plate to a coupling cap and on to power tube V3's grid. Here's the article. In exchange, you give up the ability to jumper the channels and have interactive volume controls. Jun 6, 2019 #1 I think I have my head wrapped around the concertina type phase inverter. You do not need a driver stage for 6P36S. High volume settings or using boost, delay or reverb pedals can push the phase inverter into extreme and odd sounding 'double frequency' Because cathodyne inverters don't sound good when overdriven, I would put the Master Volume before it so that the output tubes clip before the inverter does and I wouldn't scale the voltage on the inverter. The cathodyne is the most used phase splitter, probably because it's the simplest and yet quite effective. 56 the output sinewaves should appear inverted. Even a cathodyne based on ECC82 or ECC88 and maybe on ECC81 should be able to handle those 50kOhm input impedance. com/roelvandepaarWith Bottom line: use PRR's suggested values. The same stage also receives negative voltage feedback from the output. Reply reply More replies. A phase splitter is shorthand for a "split load phase inverter" (SLPI). We have boards ranging from circuit building blocks, such as Power Supply Boards, MOSFET Gain Stage / Cathodyne requires one triode and takes one output from the plate, the other from the cathode. Wide open; normal cathodyne phase splitter. So, there will usually be another gain stage just prior to the cathodyne. Fortunately, the cure is simple. That is to say the inputs are ‘flipped’ in relative polarity. Looks like its a cathodyne or concertina type (its the same thing, just a different name) phase inverter, so half of the 12AX7 is also a gain stage, and half is the inverter. a deluxe . The document discusses the cathodyne phase inverter circuit. It can be driven directly from a cathodyne or a LTP-phase inverter. 32. However, the The 12AU7 in V1 reduced the gain too much for my liking, but tonally it was a very great, classic rock sound. Cathode followers are used primarily as tone stack drivers and depending on how they are set up, also contribute to the tone. New You want perfect balance, use a cathodyne. 1 of 2 Go to page. At least the cathodyne has Ac phase and distortion balance so long as the load Newb question about cathodyne phase splitter I've drawn out a schematic for an amp which I was unable to find one for, the phase inverter section of this is pictured below. Understanding this phase inverter. IMO, those characteristics suggest mediocre performance in either a "concertina" or LTP circuit. I find this amp sounds thin with a guitar and no mids at all. PRSMesa182 The phase inverter was upgraded to a modern long tail pair which has much more voltage swing than the 5E3's no-gain cathodyne phase inverter so the long tail pair phase inverter can drive the power tubes harder and generate more power tube distortion. 1), and the other is the “Long-Tailed Pair”, derived from a circuit called the Schmitt Inverter (Fig. be/VBu-LST1p9cHere is The cathodyne phase inverter, also known as the split-load phase inverter, employs one triode tube and one resistor. Sure, as a cathodyne it would be "TEH SUXXORZ", but it would make a fine LTP, especially with a CCS cathodyne phase-inverter. The cathodyne phase inverter, also known as the split-load phase inverter, employs one triode tube and one resistor. There are Yay Orange OR120 from back in the day. Others say the tolerance of the Changing the various 12AX7s around may change the ultimate IMD readings you obtain, but it will not affect where a given tube achieves the minimum IMD produced, as this receivers uses a cathodyne (split load) phase inverter which is quite insensitive to tube replacement in the driver section. is high at 22. C18 – The Princeton Reverb type amp is a single channel amp with bias vary tremolo and a cathodyne phase inverter. differential amplifier and the "mixed" combo splitters: 5. The cathodyne phase inverter is the primary cause of the tone differences between the Princeton Reverb and other blackface amps. 2 Balanced Mode Output Resistance If the output loaded gain G bal(R L) = 0. I understand that the signal is fed in an uninverted state (I'm going to call this A) into the grid of the first half of the dual triode. With so much negative feedback, the cathodyne produces too little harmonic distortion to hear. It's used in Fender Princetons and some Gibson amp models. The Cathodyne AKA Concertina. It is a simpler and less expensive design but may introduce some phase shifting and distortion. (A true valve cathodyne has some nasty characteristics when overdriven unless you take several precautions. 1uF into 220k bias feed - I prefer 0. While browsing through some old Audio magazines I came across this article for an amplifier which uses a three triode phase inverter. For the circuit to work properly, the anode and cathode loads must be exactly equal. Additionally, looking at several commercial schematics of yesteryears, it is noteworthy that for similar (or the same) type tubes, the phase inverter circuit components values, vary widely. Thread starter Plimpington2; Start date Jun 6, 2019; P. But Peavey, Orange and many others use a cathodyne Phase inverter circuit that puts the high voltages on the cathode. I've also noticed a similar circuit in the 5E9-a Anyone had a go at using mosfets for phase inverting? Will report what i hear, but im also interested in phase inverter use as well. Fig. Filtered by: Clear All. tiscali. The phase inverter is a paraphrase phase splitter circuit and it works great when the standby is pressed but no so good when it should be quiet. dankinzelman. It's primary advantage is it only requires one half of a preamp tube (one triode). Easy to design: set the grid voltage to something between 1/3 and 1/4 of the supply voltage. The split load or cathodyne phase inverter only uses one tube stage, and has unity (or less) gain. A grounded cathode amplifier inverts the signal it sees. The long-tailed-pair offers a greater output It depends on what kind of phase inverter circuit the amp is using. Jan 26, 2013 3:51 am. I'm not sure this is really true, unless I'm missing something, at least for a 6V6 type amp like 5E3. If the phase splitter is a cathodyne, there's no possible reason to do so. Available feedback will be reduced somewhat because you're using a lower-gain tube in the phase inverter; this may reduce the total amount of presence boost available, If the output from an inverting amplifier is used as a phase inverter output, it can be sent to a second inverting amplifier to invert the phase again for the second output. What would you suggest we do with the speaker config. Unlike the non-amplifying cathodyne phase inverter used in many guitar amps the LTP phase inverter not only creates a dual mirror image signal stream but it also acts as a gain stage boosting the signal by about 1/4 of what two normal triode gain stages would. bal, hence, Just spent 5 mins googling the Rocker 32 ( cool amp ) and didn't find out which tube is the phase inverter, or even if it has one. reverb has two channels, a long tail pair phase inverter and a bit more power than a Princeton Reverb. Re: cathodyne phase inverter Post by Phil_S » Sun Aug 02, 2009 2:26 pm sliberty wrote: since the preamp used three triodes already, a single triode PI was a design decision at Vox to keep the tube count from growing. C4 – Gain stage +DC-coupled cathode follower. Our goal is to end up with two equal and opposite signals. Search. bal (= 0. Mullard: direct coupled SE to balanced floating diff amp. I built a 5e7 style amp and added the grid stopper and it sounds great when cranked. V2B (upper center) is the cathodyne phase inverter circuit. In this circuit, the pentode section of the 6BL8 is being used as that gain stage. On page 62 it should read "If the rate of closure is more than 40dB/decade (>12dB/octave)" Thanks to Yes, nothing but a generic "cathodyne" phase inverter there. I hooked up both sides of my PI output (post caps) to the oscilloscope, and lo and behold, saw exactly the pattern of anode signal distortion shown in Merlin’s book (see photo). The author has a patent on it (below), but uses a modified version. The solution here is to add a grid resistor to the cathode follower side of V4. Fullerton '63 : Reverb model produced from '63 to '67. An example of ECF80 amplifier/cathodyne. It only utilises one triode which can be economical, however it produces "less than unity" gain, so usually the other half, or triode of a twin triode is used a a gain stage directly preceding the cathodyne (as in the Princeton). 9. Basically Cathodes on preamp tubes see very low voltages, usually around 1. a cathode follower directly coupled to a grounded grid amplifier stage. The only thing that the simulation shows a bit odd is that the screen voltage of the pentode section should be fine tuned to optimum In single ended amps or amps with a cathodyne phase inverter the NFB is inserted at the cathode of the triode closes to the power tubes. split-load phase splitter (AKA cathodyne phase splitter) receives an unbalanced Gain of the Cathodyne is 1 (actually about 0. However , sound quality is (redirected from Cathodyne Phase Inverter) Category filter: Show All (168) Most Common (5) Technology (37) Government & Military (27) Science & Medicine (29) Business (59) Organizations (51) Slang / Jargon (5) And these 4 tubes can safely be driven by a LTP phase inverter using an ECC81. Hence changing the 'phase inverter' tube in an OR120 to a lower gain type will lower the overall gain of the preamp stage, but this is primarily because you are reducing the gain of the gain stage immediately The Princeton Reverb uses a cathodyne phase inverter instead of the AB763's long tail pair (LTP). C7 – Phase inverter fixed or cathode bias. Feedback goes to the cathode, as is the I have the transformers from a 2xKT88 Sunn amp, so I want build something close to the Sunn design. Open comment sort options. Actually this is a good mod for any guitar amplifier that uses a cathodyne phase inverter like the 5E3. As long as they test high and are quiet. The old cathodyne sound incredible up to a point and then falls apart into distortion. It is really just a matter of tapping off the main signal path and feeding that signal into an extra gain stage so it becomes inverted. Manual adjustment in a Support this channel via a special purpose donation to the Georgia Tech Foundation (GTF210000920), earmarked for my work: https://youtu. I already read about similar complaints with the 5E7 and the BFPR and someone here redirected me to the Valve Wizzard article that is linked above. This 12AU7 phase inverter is in the signal path, so I suppose it could make a difference to the tone. Gm is low at 1. 7k cathode bias resistor and cap-couple this stage to the inverter grid. 142. This type of phase inverter has a gain of less than unity, so it is standard practice to have a gain stage immediately preceding the PI. The long tail pair phase inverter upper triode passes the guitar signal to its lower triode through their connected cathodes. The Marshall/Fender phase inverter is commonly known as a "long-tail pair", or "Schmitt" type phase inverter, or phase splitter (actually, the original Schmitt inverter was a differential pair with a large "tail" resistor; the "standard" guitar amplifier phase inverter is a self-biased version of this circuit that works better with positive-only power supplies and explore #cathodyne_phase_inverter at Facebook For instance, with a post phase splitter master vol on a long tail pair type phase splitter, blocking distortion on the phase splitter should be obvious and identifiable, but I've never noticed it. The tube will attempt to set identical drop voltage across Ra and Rk, As you can see, when we consider the output impedance of both outputs simultaneously (in this case using two current sources, 180 degrees out-of-phase, which mimics the phase inverter operation), that both anode and I was taught many years ago that cathodyne is the circuit below i. Dan Torres makes a point about making the values of the plate (56K) resistor and the total cathode resistance (56K + 1K = 57K) equal. The Harvard was a fixed bias amplifier, using a basic cathodyne phase inverter, but did include a selenium rectifier in the bias circuit. Examples are nearly everywhere on this site. 6AN8 pentode/triode for a driver/cathodyne into KT88 UL. C6 – Cascode. Share Sort by: Best. Jump to Latest LATUBEGEEK. Does anyone have a formula for calculating the capacitor size needed between the phase inverter and the push pull power tube stage? artosalo. Author Topic: OT, Bias and Redplating (Asymmetrical Output from Cathodyne Phase Inverter) (Read 3699 times) 0 Members and 1 Guest are viewing this topic. The Classic 30 doesn't use both halfs of the 12AX7 in V3 for phase inversion. R. Caps say 1975. Cathodyne Phase Splitter. The cathodyne adds a gain of less than 2 whereas the AB763's long tail pair adds about 50% of the gain of a typical single triode gain stage (gain The cathodyne is the most used phase splitter, probably because it's the simplest and yet quite effective. It can be thought of as being I've read that the cathodyne aka split load aka concertina phase inverter suffers from inability to adequately drive the output stage. If you had a hifi audio amp that used a long tailed pair inverter, and if everything else in it was perfectly matched, then you might want a matched triode phase inverter. These are widely used in the music instrument & manufacturing industries for controlling power output. I tried a 500k Phase Splitter Ideas Okay, it's time to give circlotron a rest, but not time to forget it entirely. The 5F10 was discontinued in 1961. 5*G 0. It was something suggested to me a long time ago that I never got chance to try out. Am thinking of using EL34 for power tube and 12at7 for preamp (half of the 12at7 for voltage amplifier dc coupled to the other half acting as cathodyne phase inverter). ) IMO, a real valve is wasted in a cathodyne. I use a pre-phase inverter master volume paired with a 270k phase inverter grid stopper resistor to eliminate double-frequency distortion. This signal is inverted compared to the phase inverter input. Joined 2007. B. C16 – Serial voltage regulator . From I understand this PI is fairly unbalanced, or at least it can be, and may require some tweaks to balance both sides. 12: The Cathodyne Phase Inverter, web exclusive chapter! Errata: On page 11 it reads: 15-90j+21j+126 = 141+69j but the answer is in fact 141-69j. 1. Pros: Very simple; Performant when followed by a cathode follower before the power tubes; Can be directly connected to the previous stage; Cons: Low gain; Not very linear because of the internal capacitances of the tube Re: Cathodyne phase inverter - altering tail value « Reply #13 on: July 17, 2012, 11:24:48 pm » I had a chance to try this experiment on two identical amps 10k on the tail of the experimental amp and a/b them through the same speaker. Level 1; Posts: 85; I love Tube amps; OT, Bias and Redplating (Asymmetrical Output from Cathodyne Phase Inverter) « on: October 01, 2024, 02:22:04 pm "Because the cathodyne operates with so much local feedback, strange things happen during overload conditions, and this is the main complaint about 'ordinary' cathodyne circuits. Pre PIMV's give a much less complex gain structure since the phase inverter itself is not being subjected to clipping on the lower/upper sidebands - therefore blues playing and more harmonically cleaner players will like the pre-PI master volume better - as volume will mix a more perfect blend of power tube distortion and phase inverter distortion both - which leans itself to If the amp also uses the tweed-era split-load (aka cathodyne) phase inverter, you know you're really in tweed Deluxe territory. phase inverter 6n7. 5E3 Cathodyne phase inverter balancing. Time. And overall the setup is pretty generic too: Since cathodyne does not have voltage gain (only insertion losses) there is a common cathode amp input stage for voltage amplification. not so much (and it's far noisier) The pro definitely doesn't have as much gain going on. patreon. If you need and want to add a grid stopper to the phase inverter, go for it. pdf), Text File (. rifraf50. It can be thought of as halfway between a gain stage and a cathode follower. Top. the peavey has a cathodyne PI which Translations in context of "cathodyne phase inverter" in English-German from Reverso Context: A pre amp as in the Silverface Champ and a power amp with cathodyne phase inverter. i`ve got a schematic of it but i do better with a layout. I was unhappy with the overdrive sound which I found raspy and thin. Since I like the Van Scoyoc cross coupled inverter, this one stood out. It provides two outputs that are 180 degrees out of phase. I've heard the Komet Concorde has this setup but that its debatable whether it actually has a benefit in its configuration. 6 mA. 2. The phase inverter tube can definitely affect the amp's overdrive. Show. 5volts or less. A long-tailed pair phase inverter can supply quite a bit of gain, but requires another tube stage. So if you had a 12AX7 or a 12AU7 in that position because of the 100% negative feedback both tubes will give the same output, both produce a gain of one. The cathodyne inverter, if we are talking about the specific triode at Phase splitters/inverters are used primarily in push-pull (AKA differential) amplification. A big difference between cathodyne and LTP is the cathodyne has no gain, but LTP does. pdf. "paraphase" inverter 4. The calculator computes the voltage gain One of the minor changes to the Fender schematic involves the cathodyne phase inverter: I wired it so that it will take a 12dw7 in that position. 95) so the Common cathode amplifier (gain stage) preceeding it in the power amp is used to get the sensitivity up such that a signal level of about 1V is enought to drive the power section to full output. Joined 2010. It's probably the second most common PI I've found. But the one below is less clear to me: The cathodyne/concertina PI does not introduce high frequency imbalance if the output circuits are This may be the cathodyne phase inverter distorting, which is also sort of like blocking distortion. Now I want to perfect this PI circuit. Using a single input channel frees up a gain stage to drive the deep, rich bias-wiggle tremolo. Cathodyne Phase Inverter. Best. Chapter 12: The Cathodyne Phase Inverter The cathodyne * is the quintessential phase inverter –beautifully simple and absolutely balanced when used properly. Some makers substitute different or more powerful output tubes and add a variety of modifications without entirely fully disguising the DNA of the original. The cathodyne phase inverter is the primary cause of the tone differences between the Chapter 12: The Cathodyne Phase Inverter The cathodyne* is the quintessential phase inverter –beautifully simple and absolutely balanced when used properly. It I've got a few 12sc7 tubes kicking around and I was thinking about using one for a phase inverter. two things in particular, would be using a cathode follower to drive a phase inverter. A cathode follower does not. Or a single triode such as the 6J5 as input/phase inverter (cathodyne) then it feeding a 6SN7 driving each half of the push pull outputs. Or a 6SN7 as a driver and phase inverter (cathodyne) then it's feeding The Long-Tail Pair. PM me if you'd like to discuss trying a standard ECC83S in the P. They also can be used as a type of cathodyne Phase inverter, typical on Orange amps and some of the Peavey Classic 50 designs. Add a large grid stopper to Unlike the non-amplifying cathodyne phase inverter used in many guitar amps the LTP phase inverter not only creates a dual mirror image signal stream but it also acts as a gain stage boosting the signal by about 1/4 of what two normal triode gain stages would. I have a question in hoping someone will be able to a answer. The Concertina is one of the oldest splitters to be used, one the first after transformer coupled splitters were jettisoned because of the cost. IOW, the princeton three triode plus cathodyne could be considered a two triode + cathodyne phase inverter with gain. This added gain gives its output more voltage swing to drive big bottle power tubes to a fully distorted state. By manually adjusting AC balance at the phase inverter stage, you can compensate for imbalances in the phase inverter itself, and imbalances down the line. 224 10 The Concertina Phase Splitter or Cathodyne (CPS) 10. Someone told me that my amps are all based on a cathodyne phase inverter design and that my ears must be tuned to liking this? I have no idea what this means, but seemingly it's common to both the LJ's Hiwatt and Twinolux. I LOVE the change in tone from the paraphase inverter. Thread starter LATUBEGEEK; Start date 2013-12-05 7:45 pm; Status Not open for further replies. So far what I have seen is that the second triode does not invert in standby so the shorted outputs do not cancel and you can hear it since it is amplified by the power stage. Feed this driver from the same 350v node as the phase inverter. /V. A stereo power amp at 15w a side running 2 x el84's a side must be class A right? No phase inverter needed. Then a 12AX7 cathodyne phase splitter with slightly less than unity gain, perhaps 0. Budget: Marsh Amps Tweed 5E3 Replica; High-End: Clark Beaufort; Anyway, the 299 used an ECF80 phase inverter and I've re-drawn the circuit (attached) but am wondering if anyone else has used this design and how it compares to some of the others. All Discussions only Photos only Videos only Links only Polls only Events only. You see, when a follower and an The calculator plots gain versus frequency for three phase inverter types: the long tailed pair (LTP), the paraphase, and the concertina, which is also known as a split-load or cathodyne. zuisq hpgq rbntnjz tjr pkrte rftmosh vsb xifuzmr ecohe pul