12ax7 cathode follower

One 12AX7 recovery stage connected to global negative feedback with Presence control. Then a 12AX7 single triode cathode follower with slightly less than unity gain, perhaps 0.9; 3. Why? It is a 450V/0.07A device with the type number ZVN0545A. In AB763 amps (with reverb and tremolo), you already have 6 preamp tubes. For the past few years, Mesa has been using two types of 12AX7 tubes: ones originating in Russia (Sovtek EH), and ones originating in China. We say yes this kind of 12ax7 Cathode Follower graphic could possibly be the most trending topic behind we portion it in google gain or facebook. The ECC99-based driver stage will develop a good amount of Miller-effect capacitance, which the 12AX7's meager 1mA of idle current cannot cope with, but which the 5mA of idle current from the 12AU7 can. There's a lot of (very informed) internet chat about why certain tubes do and don't work as cathode followers. Ef86-12ax7-12ax7+cathode follower-12ax7+cathode follower-EL84. It's a cathode bias together with a cathode follower together! Fat C PI 12AX7 Fat & TT C stage 1 & TT C stage 2 12AX7 TT C PI 12AX7 Fat C stage 2& cathode follower EL84 EL84 EL84 EL84 Dual Terror Power Amp What are the ups and downs of running a 12ax7 (cathode follower, gain stage, and phase inverter) below the minimum 5.67 V (6.3 -10%) design specs? A 12AU7 can take a much higher amount of plate current than a 12AX7 so by substituting the "12AU7" side, you increase the gain and lower the headroom, and an SVT already has TONS of gain. In general, there are only a few reasons to use a cathode follower: 1. Regular SLO100 tonestack. A lot of folks like the Tung-Sol or the Mullard RI in the gain slots (V1, V2). 12AX7 vs 12AT7 vs 12AU7: Differences Explained. Can't see any reason why this one wouldn't work as well as any other new 12ax7 in those type of circuits. This leads me to believe that Tung-Sol rectified whatever design issue they had. The circuit posted is a common cathode (1'st stage) stage feeding a cathode follower (2'd stage). We use the 12AX7 triode as the input tube and the 12AU7 as a cathode follower. A "classic" design that's typical of 1960s hi-fi equipment uses a high gain triode such as a 12AX7 as a grounded cathode amplifier, coupled to another triode acting as a cathode follower. Can't find any reference to 7119. Philips 12AX7S says 100v, but this may be artificially-low to meet claimed low heater-to-cathode leakage current. Using a 12AX7 as a cathode follower yields an output impedance that's roughly 1/10th that of a common cathode voltage amp using a 12AX7. Gain 8,6. Pick your favorite, then move to V2, etc. Could I swap out my current manufacture Electro Harmonix 12ax7 tubes into my guitar amp? Lloyd. why low rp tubes and cathode follower circuit work for preamplifier output stage왜 프리앰프 출력단에는 낮은 플레이트 내부저항을 가진 진공관이 필요할까요. Our lead designer favors the 12AX7, and that does seem to be the number one choice - other tube types seem to burn out very fast, or not be reliable, or whatever. Plug into a clean amp, a loop return, or even a big SS power amp. How would this differ from the function of a typtical Driver tube (such as a 6SN7, 12AX7, 12AU7)? Help with re-biasing an atypical DC-coupled cathode follower. Based on the Soldano SLO100. I got rid of the clean option and added a very useful bright pot. But I have found that such a concern for 12AX7 was proved unfounded through the results of Handoko-san's Model 7's modification. 2 x 12AX7 + cathode follower (IRF820 source follower). but i see all these warnings about cathode followers. Found 156 records in Search of Tube DIY Asylum.. 1: White cathode follower and Complex cathode follower (15.07) Posted by Eric Chan on 2003-01-22, 18:33:14 (161.114.1.182) Could someone in this forum give me some information/basic calulation regarding the following two topology 1. Dave Hecht I wouldn't use a Tung-Sol in a cathode follower, because it is a tone tube. In the 5F6-A, there is an extra unused triode if you don't include the cathode follower. So, I'm working on step 1 of my plan outlined here to improve the sound of my Blackheart Killer Ant amplifier (2 x 12ax7 tubes, 1/4W, Class A) by replacing the 12ax7 "power" tube (V2) with a 12au7 for more clean headroom. Share on other sites. One final thought, the 12ax7 in v2 may not be the best choice for a cathode follower, since the 12ax7 is designed to be a high-gain voltage amplifier. 15 Profiles 11 Profiles. Master the basics Design your amp Know it works Amp Design for the 21st Century. V3 is the driver and cathode follower for the tone controls. V2 is the tremolo oscillator. For example, don't expect a 12AX7 based Cathode Follower to drive a 600 ohm load to 10 volt peaks just because it has a 600 ohm output impedance. Half of the remaining 12AX7 dual triode was operated as a second gain stage, which in turn drove the remaining section as a cathode follower. - Jsawyer09 19:41:37 09/04/19. Like any triode, the 12AX7 operates with more linearity the larger the plate. The Shuguang 12AX7 that is sold under (Ruby, Penta Labs, etc), JJ 12AX7's and of course NOS tubes all can take the Cathode follower position. This Russian tube has strong lows and bright highs. The biggest difference between these power tubes is the amount of gain they will provide. Chinese, JJ, Sovtek, Tung Sol RI, EH 12AX7's are not that expensive, and the ones you don't use become your backups. 12AX7 with an 820Ω cathode . Aug 3, 2012. The 12AX7 has a gain factor of 100, while the 12AT7 has 60. The triode uses contact bias for simplicity, but of course cathode bias could also have been used. Tung-Sol 12AX7's had a great record with very few complaints or returns. Topic - Art Audio Vinyl One owners: which 12ax7 variant as a cathode follower? The triode in a 7199 is pretty close to a 12AU7. Think they might be worth anything on eBaY? Brimar 12AX7 says 250v. There is grid current on the grid of the CF, which also affects the plate voltage of the cathode bias gain stage. ). A cathode follower with R k =∞ would have the same gain, . From the plate, the signal is now strong enough to drive the voltage doubling rectifier. This corresponds to a bias current of 0.75 mA. Don't make the mistake of thinking solely in terms of voltage—current is equally important in a buffer's design. In all honesty, this is just too tough a load for most tube preamps, with 12AX7 cathode-follower preamps falling down the worst. Usually 12AX7's have a limitation on the heater voltage (heaters are inside the cathodes) and the voltage on the cathode. Without this cathode follower circuit, the tone control addition would have reduced both gain and sound quality and become a negative factor for this amp design. Despite its detractors, the 12AX7 is actually intrinsically very linear, even more so than the 6SN7 in the test I did. The 12AX7 has a gain factor of 100, while the 12AT7 has 60. Fourth Stage 12AX7 Preamp and Cathode Follower The fourth stage drives a cathode follower that drives the SLO's effects send. As for more technical . The problem would seem to be the "maximum heater relative to Cathode, negative Voltage" in the case of the 12AX7, this is rated at, in many peoples eyes optomistic, 180Volts. Times have changed. - Timbo in Oz 02:04:46 09/09/19 (1) RE: Using a 12AX7 as a CF is a dumb idea. Specifically, in a 12AX7 tube used as a "cathode follower", the voltage difference between that present at the cathode, as compared with the heater voltage, can be withstood or tolerated by certain types of tubes, whereas other tubes will fail. We identified it from trustworthy source. Spiral filament 12AX7 tubes have problems in cathode follower circuits due to the fact that most cathode follower circuits in guitar amplifiers exceed the maximum cathode to heater rating of 100 volts. The 12AU7 has the smallest, at just 20. The 12AX7WC has closely matched sections making it ideal for phase inverter circuits. guitar tone stack, may not sound as well as the cathode [1]. Here are a number of highest rated 12ax7 Cathode Follower pictures upon internet. In a cathode follower, it sends the signal out into the rest of the circuit. Suppose we use a 12AX7 vacuum tube and we want to set the operating point at the red spot in Figure 8, using the green loadline. Two stage 12AU7 preamplifier with low impedance output stage. There is a youtube clip up - search "Phaez Asheville Preamp" One half of the 12/20's V3 is a cathode follower and the other half is the cathodyne phase inverter, so you might have trouble with a Tung Sol 12AX7 in V3 there was a guy in the jvm forum who contacted new sensor regarding the issue and this is the answer he got from them: "The Electro-Harmonix 12AX7EH has a spiral filament and should not be used in cathode follower circuits. The ECC83 (also known as the 12AX7) is the most commonly used preamp valve. My point is that the RCA and Sylvania tube manual specify close to 300 volts of cathode/heater differential, which it's doubtful any guitar amp exceeds. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features Press Copyright Contact us Creators . The failure of a "cathode follower" tube will cause sound dropouts or signal loss. Some vacuum tube op amp manufacturers provided chopper-stabilizer "add-on" units. If you really need line stage gain, the linked PCB will work fine, with 12BH7 s populating the sockets. I tested it - first straight off the plate of my 12ax7 first gain stage - and unsurprisingly, it was too dull. A rectifier is a diode that converts AC to DC. What I have done with a good number of my amps is to start with V1, swap in 4 or 5 tubes, write down and/or record the each tube in V1. NOS JAN 12AX7s are recommended for this position. 일본 . The Bassman cathode follower has according to the schematic, 215 Vollts on the cathode, minus your 6.3 heater, still leaves you in excess. Regular $383. We'd need to add yet another to include a cathode follower for the two tonestacks. This circuit works well and sounds superb. #2. RCA 12AX7A says 200v. So, the gain is 80 x 0.9 x 0.9 = 64.8 For more information about our 12AX7 tubes, see our tech corner article on 12AX7s. Topic - Art Audio Vinyl One owners: which 12ax7 variant as a cathode follower? Typically 12AX7's have a heater to cathode limit of 150 to 180 volts. cdn$269 ON SALE!!!! As a solution, I've added a 12AX7 tube and cathode follower circuit to add back the lost gain. Author in some of his following works has perfected the follower, using a low-power transistor LND150 and significantly simplified the scheme [2]. Typically that tube swap is not a problem. The overall gain is about 8 times. Since every portion of a typical linear power supply in a vacuum tube amplifier is coupled (in part) to the output, changes in any component in a power supply can often radically effect the resultant sound - rectifier tubes, power transformers, resistors, capacitors, and inductors all can and do effect the sound. The important concept to grasp is that any cathode follower is a greatly improved output impedance, and a 12AX7 as a voltage amp is generally more desirable than a lower gain and/or higher current triode. Cheers Ian It's like a lot of things: it's not the use, but the mis-use, that causes detractors. Also, what is a "Getter" tube? 1. V3 is the cathode follower position, and the tube used here needs to be tough. The clean tones were full and rich, and once pushed past 'clean . A second gain stage consisting of one half of a 12AX7, leading to a 12AX7 cathode follower that drives a tone stack with independent treble and bass controls and local negative feedback. The second 12AX7 triode is not used as a cathode follower, as it may seem at first glance, but the control voltage is used to control its conduction. Significant elements of this design were the 12AY7 first stage preamp, the 12AX7 cathode follower tone stack driver and long-tail phase inverter, the pair of 5881 fixed bias output tubes, the 5AR4 tube rectifier, and the four Jensen 10″ speakers in an open backed cabinet. Cathode Follower Calculator. I think the design "visually works better" when the output from the source is either direct to source or after the first source resistor (R33) - the waveform more closely replicates the wave of a 12AX7 cathode follower. This book examines this famous amplifier by studying its circuit design in great detail. On that note, a 12AU7 really doesn't make a very good cathode follower. When a Tung-Sol 12AX7 dies in a cathode follower with 30 volts on the cathode, or in a phase inverter where the cathode might be 80 volts over ground, then it's the tube, not the circuit. The cathodyne phase inverter is very similar to a simple cathode follower except half of the load resistance is placed on the cathode and half on the plate so half of the voltage swing is on the cathode and half on the plate. Permalink. The lower gain of the 12AT7 and 12AU7 also allows them to have a higher headroom, which can provide a warmer . From the plate, the signal is now strong enough to drive the voltage doubling rectifier. The ECC83 / 12AX7 is a weakling in this regard, although for guitar applications it is often 'good enough'. Also, would a driver tube typically have more affect on the overall sound (i.e. They're actually, conveniently, two small valves in one glass shell, with two symmetrical sides that can be fed directly into one another (known as cascading gain stages) to create a big signal at the output for any . The SVT's preamp uses the 12DW7 (half 12AX7, half 12AU7) with the "12AX7" side as a gain stage and the "12AU7" side as a cathode follower. Just a treble cut on both controls. V3 is the cathode follower position, and the tube used here needs to be tough. The best rule of thumb may be to split the difference between cathode voltage of normal grounded-cathode stages and the cathode voltage of follower stages. The bias point of the CF is set by R4, if R4 would be 100K or even lower (such as on a VOX amp), the current goes . 12AX7 single triode input stage with plenty of gain, perhaps 80; 2. gm = 2.25 mA/V for 6N2P and 1.6 mA/V for 12AX7 So rp will be a little lower for the 6N2P - likely a little cleaner (less distortion) in Guitar Amp duty. TUNG SOL 12AX7 reissue,EH 12AX7,SOVTEK 12AX7LPS,MULLARD 12AX7 reissue. Without negative feedback, this type of circuit has very high gain (around 80) and distortion, and high output impedance. 12ax7 cathode follower is pretty common in guitar amps. The Russian (Sovtek) tube is NOT reliable as a cathode follower. 12AT7s may not function here. A second gain stage consisting of one half of a 12AX7, leading to a 12AX7 cathode follower that drives a tone stack with independent treble and bass controls and local negative feedback. Did you mean 7199 ? Oct 6, 2016 - 12AU7 (ECC82) Cathode Follower Tube Preamplifier Schematic. Fourth Stage 12AX7 Preamp and Cathode Follower The fourth stage drives a cathode follower that drives the SLO's effects send. My unit uses a sss has three-tube reverb mix stage. Designing an AC Cathode Follower For the following example we will design a cathode follower to act as a buffer for an effects loop. jbmojo 2,054 2 This tube is also bootstrapped; the positive feedback is necessary to derive the very high AC drive voltage required for the output stage (remember the cathodes are in the . This position is not critical, though a 12AX7 with reasonably high gain is required. Cheers, Ian ••• DA: 79 PA: 76 MOZ Rank: 56 You need a low output . In the case of GAP/R, this was the GAP/R K2-P. Grade 2 (higher than average microphonics) Not recommended for V1 but good for phase inverters, cathode followers, tremolo tubes, $25.00 Taxonomy upgrade extras: Catalog's Front Page right now i. In overdrive, it offers a lot of crunchy fizz. Placing it at the "traditional" resistor to ground (R13) significantly clips the negative side of the signal. Jim Marshall crafted guitar amplifier masterpieces without the assistance of computers, software or the Internet. Most of the New Sensor Tubes can only handle . The common cathode stage provides voltage gain but, by it's nature, a cathode follower (2'd stage) has no voltage gain; but does have CURRENT gain, which is why it's used when driving loads (like a tone stack or long, capacitive, preamp cables, etc. Link to comment. Then I installed the cathode follower (using an IRF-820, since this is a small and tight build in a tiny chassis, with just 4 tubes: 12ax7, 6au6, EL-84 . The triode uses contact bias for simplicity, but of course cathode bias could also have been used. Cathode follower = classic tones. The 12AU7 contains non-linear triodes. (12) Using a 12AX7 as a CF is a dumb idea. You will need double the heater current. Maximum point can be found experimentally by achieving minimum distortion of an unloaded cathode follower at high signal level. I was looking at a schematic last night which is the same as what I would like to build but it used an el84 as a cathode follower. When they are set up as cathode followers, the cathodes can see 150 to 200 volts depending on the design. Reply. The 12AU7 has the smallest, at just 20. The fourth stage is configured the same as the first but with just a slightly higher plate supply voltage, so it has approximately the same DC operating point: a DC plate-to-cathode voltage of 176V and a cathode-to . 12AU7 has over twice the plate power (Ppd) capacity of a 12AX7, which makes IT excellent for cathode-follower operation (in addition to its much lower 7.7KΩ rp). - Jsawyer09 19:41:37 09/04/19. The second 12AX7 triode is not used as a cathode follower, as it may seem at first glance, but the control voltage is used to control its conduction. TOPOLOGY Two independent 12AY7 channels, each with high and low sensitivity inputs. Fender, Marshall, Hiwatt, Orange have all used a 12ax7 follower on many of their models. In 1963 "graphical methods" meant drawing Bode plots with a pencil and ruler. But you are right on with the cathode follower! 6 yr. ago. There were proposed also solutions which allows to make sound of the follower on MOSFET closer to follower of 12AX7 (ECC83). Spiral filament 12AX7 tubes have problems in cathode follower circuits due to the fact that most cathode follower circuits in guitar amplifiers exceed the maximum cathode to heater rating of 100 volts. The third tube is wired as a cathode follower buffer stage, which has no gain, and therefore substituting a 12AU7 in that spot won't affect the preamp gain. Cathode followers have relatively high cathode voltages, and cathodyne phase inverters also also have fairly high cathode voltages. 12AX7WA/WB/WC types hold up better than other 12AX7 tubes in cathode follower circuits where the maximum cathode to heater rating of 100 volts is often exceeded. Given 100% local current NFB, the 'U7 is OK in the cathode follower role. Its lows demand attention when playing full bar chords. The failure of a "cathode follower" tube will cause sound dropouts or signal loss. Zetex makes a TO-92 package MOSFET worth some consideration for replacing 12AX7 followers. As such, the type makes a poor voltage amplifier. The ECC82/12AU7 is well suited to this job because it is cheap and plentiful, its low internal anode . 12AX7 vs 12AT7 vs 12AU7: Differences Explained. Tung Sol 12AX7 says 180v. 1. (12) Using a 12AX7 as a CF is a dumb idea. This squares with the empirical evidence of listening to it - it sounds the same as when a triode is used as a cathode follower. I wouldn't recommend a DC coupled cathode follower for hifi applications But I love them and always use them in in guitar amplifiers. Then a 12AX7 cathodyne phase splitter with slightly less than unity gain, perhaps 0.9. Heater cathode max voltage is 100V for 6N2P vs 150V for 12AX7 - watch this in cathodyne phase splitters and cathode follower use. Preamps with 12AU7 cathode-followers aren't much better, sounding very "tubey," rolled-off, and old-fashioned. - Jsawyer09 08:27:58 09/09/19 (0) At the time it was made, were 12AX7s massively cheaper, or was the company too cheap to as a cathode follower? It starts by breaking the amplifier into its major components: the 12AY7 preamp, the 12AX7 voltage amp, the 12AX7 cathode follower, the tone stack, the long-tailed-pair phase splitter, the push-pull power amplifier, and the power s Supposedly the Sovtek 12AX7WC can take the higher cathode voltages. 5E7 Bandmaster. The 5687 has more Gm than a 12AU7, but burns three times the heater current. The Mullard cathode is perfectly round, with a thick, even coating (except where it got scratched removing the grid). The biggest difference between these power tubes is the amount of gain they will provide. 12Au7 would be a better choice this famous amplifier by studying its circuit design in great detail, though 12AX7! Total differential gain is required it works amp design for the 21st Century between these power is... ( around 80 ) and distortion, and high output impedance a clean amp, a loop,! Three times the heater current act as a CF is a tone.... Good quality doubling rectifier ; clean Tung-Sol in a cathode follower for the tone controls 60... Philips 12AX7S says 100v, but of course cathode bias could also have been used of 100, the! Reverb and tremolo ), you already have 6 preamp tubes inverter circuits ; )... no science..., there are only a few reasons to use a Tung-Sol in a cathode together... A driver tube typically have more affect on the grid of the option. To use a Tung-Sol in a cathode follower follower role the 5687 has more Gm than a 12AX7 as CF. This type of circuit has very high gain is required yet another to include cathode! The linked PCB will work fine, with a DPDT ; add-on & quot Getter! 12Ax7 single triode cathode follower ( IRF820 source follower ) a TO-92 MOSFET. > which tubes hold up in a chathode follower a loop return, or even a big SS amp... Cf is a & quot ; units Presence Control my guitar amp 0.0032″ thick the clean tones were full rich... - watch this in cathodyne phase splitters and cathode follower: 1 phase splitter with slightly less than gain... U7 is OK in the cathode follower ( IRF820 source follower ) d need to add yet another to a. Pretty close to a bias current of 0.75 mA assistance of computers, software or the RI... Master the basics design your amp Know it works amp design for the tone controls with very complaints... Ab763 Amps ( with reverb and tremolo ), you already have 6 preamp tubes straight off the plate my... Would a driver tube typically have more affect on the overall sound ( i.e gain of follower! When playing full bar chords unity gain, the signal is now strong enough to drive the voltage doubling.! Move to V2, etc stage gain, perhaps 0.9 ; 3 plug into a amp. Have 6 preamp tubes sensitivity inputs works amp design for the 21st Century has... - Timbo in Oz 02:04:46 09/09/19 ( 1 ) RE: Using a 12AX7 a... Book examines this famous amplifier by studying its circuit design in great detail What... Strong enough to drive the voltage doubling rectifier very useful bright pot CF, which can provide a.! Only 0.0032″ thick, because it is cheap and plentiful, its low anode. Has strong lows and 12ax7 cathode follower highs to include a cathode follower ( IRF820 source follower.! Such, the signal is now strong enough to drive the voltage doubling.! 12Bh7A vs. 12AX7 ) and distortion, and high output impedance dumb idea impedance output stage without... Scratched removing the grid ) in general, there are only a few reasons to use a Tung-Sol in chathode. Complaints or returns unit uses a sss has three-tube reverb mix stage it is a idea! 12Bh7A vs. 12AX7 a bias current of 0.75 mA slots ( V1, V2.. Perhaps 80 ; 2 of 0.75 mA s populating the sockets, it offers lot... 100 % local current NFB, the signal is now strong enough to drive the voltage doubling rectifier three the... - Music... < /a > Tung Sol 12AX7 says 180v Fractal... < >! 12Au7 also allows them to have a heater to cathode limit of to! The triode uses contact bias for simplicity, but burns three times the heater current ; 12ax7 cathode follower drawing plots... Meant drawing Bode plots with a pencil and ruler attention when playing full bar chords a 12AU7 for cathode with! Low heater-to-cathode leakage current < a href= '' https: //www.rig-talk.com/forum/threads/tung-sol-ri-12ax7-vs-cathode-follower.76952/ '' > cathode follower:.... Diyaudio < /a > Tung-Sol RI 12AX7 vs cathode follower it is a idea.... < /a > Help with re-biasing an atypical DC-coupled cathode follower pictures upon.... Smallest, at just 20 0.0032″ thick, there are only a few reasons to a! No rocket science: //www.harmonycentral.com/forums/topic/1312212-which-tubes-for-cathode-follower-stages/ '' > Tung-Sol RI 12AX7 vs cathode follower cause sound dropouts or signal loss,... Typically 12AX7 & # x27 ; U7 is OK in the cathode bias gain stage - and,. 12Ax7 vs cathode follower stages the heater current gain is slightly less than unity,! 12Au7 also allows them to have a heater to cathode limit of to... The sound of the 12AT7 and 12AU7 also allows them to have higher. Output impedance overall sound ( i.e splitter with slightly less than unity gain perhaps... Famous amplifier by studying its circuit design in great detail provide a warmer &. Has a gain factor of 100, while the 12AT7 and 12AU7 also allows them to have higher... The internet, a loop return, or even a big SS power amp at just 20 12AX7 - this! This book examines this famous amplifier by studying its circuit design in detail. A href= '' https: //www.harmonycentral.com/forums/topic/1312212-which-tubes-for-cathode-follower-stages/ '' > Best 12AX7 for cathode follower because!, which can provide a warmer V2 ) the heater current also affects plate... My unit uses a sss has three-tube reverb mix stage big SS amp... Dumb idea any triode, the 12AX7 has a gain factor of 100, the! 12At7 and 12AU7 also allows them to have a heater to cathode limit of 150 180! To include a cathode follower use with slightly less than unity gain perhaps! Https: //blog.thetubestore.com/what-the-tubes-do-in-most-marshall-tube-amps/ '' > cathode follower for the following example we design... > 5E7 Bandmaster crunchy fizz gain factor of 100, while the 12AT7 and 12AU7 also allows to. Rectified whatever design issue they had have more affect on the overall (... Mix stage i tested it - first straight off the plate, the type a! The sound of your preamp? coating ( except where it got removing... This job because it is a dumb idea corner article on 12AX7S reasonably high gain ( around )! In cathodyne phase splitters and cathode follower for the two tonestacks already have 6 preamp tubes but see! Of computers, software or the internet graphical methods & quot ; units where it got removing... Perhaps 0.9 ; 3 a warmer and plentiful, its low internal anode rocket science source follower.! Design issue they had has strong lows and bright highs a TO-92 package MOSFET worth some consideration for replacing followers! Is required computers, software or the Mullard RI in the cathode bias stage. No rocket science: //forum.fractalaudio.com/threads/cathode-follower-again-no-rocket-science.74247/ '' > Tung-Sol RI 12AX7 vs cathode follower with slightly less unity. Power amp > cathode follower for the tone controls great detail overall sound ( i.e our tech corner on. The plate What the tubes do in most Marshall tube Amps... < /a > we the. It is a 450V/0.07A device with the type makes a poor voltage amplifier 6 preamp tubes we #! The tubes do in most Marshall tube Amps... < /a > we use the 12AX7 has a gain of. A good as a cathode follower pictures upon internet perhaps 0.9 ; 3 got scratched removing the )! A big SS power amp lows demand attention when playing full bar chords feedback with Presence Control effects loop low. Tubes, see our tech corner article on 12AX7S which tubes would you roll out first you! To make sound of your preamp? ), you already have 6 preamp tubes amp design for two... Scratched removing the grid of the follower on many of their models, then move to V2,.. Uses contact bias for simplicity, but not as a cathode follower & quot ; add-on quot! Most Marshall tube Amps... < /a > Tung Sol 12AX7 says 180v ; cathode stages... Crunchy fizz of circuit has very high gain ( around 80 ) and distortion, and once past. Must be good quality and bright highs any triode, the signal is now strong to. Bias gain stage - and unsurprisingly, it was too dull would a driver tube have. Single triode input stage with plenty of gain they will provide across.The material itself is only 0.0032″ thick ''. Ecc82/12Au7 is well suited to this job because it is a tone tube heater cathode max is... Software or the internet fine, with a cathode follower pencil and ruler - Music

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