Simply put, the Maz Jr. The name is logical because the cathode potential varies with and is almost equal to the input voltage. I will call my adaptor DAC board a LAMPUCERA. 6L6GC Author: RCA Subject: FP-2012-01-07 Created Date: 1/8/2012 12:17:39 AM. An ECC88 is employed for the cathode follower instead of 6BQ7A, running at around 8ma current. So when an EL84 fails is it possible that it's filament will still be intact and feed voltage to the other series connected output tubes?. The Rib plate is also a very good quality tube. R4 provides a load for V4 when grid current is not needed for V1. I wouldn't use it for the basic drive tube for a pre-amp because an additional cathode follower is needed to get the low output impedance in a typical circuit. With a sensitivity of 101dB, our custom. This is possible because the grid is biased negatively compared to the cathode (the negative bias is what allows it to modulate electron flow). Royal Albert-45 Watt (2xKT77), solid state or tube rectified, dual 12AX7. Typical operating conditions for two EL34 la (max. Again, a great sounding tube but for much less money compared to NOS Mullard EL34 vacuum tubes. In addition, a cathode bypass cap of 0. 7 Tube Stereo Output Amplifier. May 10, 2017 - Direct-Coupled 6V6 Cathode Follower Tube Amp Schematic. 7nF VR4 500K-A BASS C15 3. Im now intrigued by the idea of sticking some 5881's in along with the cothode follower Mod. An early Audion has maximum unregenerated voltage gain under 10. Or we could use one tube type for the input triode, such as 6N1P and an EL84 for the output tube. Pin 1 of the 12AX7 in Figure 3 is attached to Z in Figure 2. So, input starts with high impedance front-end pentode (ef86), followed by overdrive section based on a triode and cathode follower (12ax7), next comes passive tone stack and at the end el84 drives the 10inch speaker through the dedicated transformer. 4, 8, 16 ohm outputs. In (b) , the bias resistances are replaced by their parallel equivalent Rg. 01 Duelund CAST tinned-copper coupling caps when I. Cab Dimensions – 18”W X 10”H X 9-1/2”D. These EL84-based class-A beauties are entirely hand-wired in the lauded point-to-point style, and deliver classic British chime, shimmer, and crunch, but with a certain modern clarity and fidelity and a bulletproof robustness relied on by countless pros. A lot of this is down to the harmonics, generated by the cathode follower stage, that enrich the output signal. The EXTRA CHIMEY is based on our popular Extra Spanky model tube guitar amplifier – but with a vintage “AC” flavor! We started with our EF86 driven AC preamp from the 3rd Power Dual Citizen amplifier, added a cathode-follower tone stack feeding our Citizen Loop, and paired that up with a quartet of EL84 output tubes. In the case of a cathode follower, all of the current does so; with parafeed it is a small portion, and with the current source loaded voltage amplifier a tiny portion. The Sovtek Long Plate Spiral is a great tube in either V1 or the Phase inverter socket. The electrodes are connected inside the tube. The Marantz 7c circuit, with it's third cathode-follower stage, does not have this limitation. The el84s are seeing 270v and biased with a 180 ohm resistor which according to weber's bias calculator is giving me 7 watts/ tube. SoHo - 20 watt (2 x EL84) or 35 watt (4 x 7591), Tube rectified, EF86-12AX7 cathode follower. This is possible because the grid is biased negatively compared to the cathode (the negative bias is what allows it to modulate electron flow). Having said that, I tend to use matching tubes for what I call positions 3-5, which are the cathode follower, reverb/effects loop mix, and phase inverter. Driver and 300b. 18watt Technical Discussion. A cathode follower, V4, which in most cases can be a 6C4, reproduces the voltage appearing at the plate of V2 but in addition supplies grid current to V1 when needed. In Colby and Park amps, I use Tung Sol, Chinese, and JJ 12AX7 tubes, as well as the Sovtek 12AX7LPS. The gain of EL84 will be 18, reduced to 0. Released January 2007. The complete contest submission. Projects I Like & Follow. These tubes are some of the best sounding tubes you can get. is his best selling amp. England (October 18, 2019) -- Victory Amplification proudly announces VC35 The Copper, a 35-watt all-valve head in the popular Compact Series. The Maz Jr. transformers for headphone amplifiers We offer a range of headphone transformers for single ended drive and drive from an ac coupled cathode follower. SS Rectifier. 18/dez/2017 - Direct-Coupled 6V6 Cathode Follower Tube Amp Schematic Stay safe and healthy. The EL34 is a man for a man's job, OK. It does NOT have a differential cathode follower, what is there, is a differential amplifier with a cathode. hi guys, i'm waiting on 3 JJ ECC83's and a Tung-Sol reissue 12ax7 for my DSL100, as it's the best compromise for my preferred tone + (drug) budget. The triode, however, is useless as a voltage amplifier and is best kept to cathode follower and phase splitter functions. See more ideas about Valve amplifier, Vacuum tube and Circuit diagram. With the floating grid circuit this leakage current is reduced to about 10- 12 A. Although, the 6H30/6C45 amp uses the 6H30 as a cathode follower, direct coupled to the cathode of the 6C45. Output power is 5. Driven by two 12AX7’s, one for the Input Stage and the other is a "cathode follower" for Tone. Ok, so in search for a perfect second amp to my lazy j20, over the past few weeks I've been buying some smaller amps of each tube family to finally compare the tone and feel of the four main families. 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. Like the Compact Series amp, this one uses a mix of xed and cathode bias in full-power mode and is cathode biased in low power. These have less clean headroom, so they'll distort at lower volumes, but the distortion is usually warm and smooth. (1mA cannot drive 600pF!) Preamps with 12AU7 cathode-followers aren't much better, sounding very "tubey," rolled-off, and old-fashioned. Cathode Followers The poor cathode follower; it gets little respector too much. Early Fender Bassmans, the Marshall JTM and several Vox amps were all. ) This amplifier is also able, via a capacitor straight from the cathode and without inductive coupling, to drive my old Philips 800 ohms wide banwidth speakers, namely the AD 5038, also rare. The quiescent current of each power stage is set by R71 and R73, which are bypassed by. The Tung Sol 12AX7 is warm and big musically. The Fender Blues Junior uses two EL84 output tubes which are fixed biased as opposed to cathode biased. No distortion figures were quoted, and the damping was not very good (the output impedance was 23 Ohms) but the authors. TUBES: Input-6N6P Rectifier-EZ81. The TU-8500 has a switch on the back (not very conveniently located) that cuts the gain to approximate a tube buffer, or unity gain circuit. High gain, super low microphonics, and superb linearity with a three dimensional tone. Haas Hrt-a6 Hrt-210 Rotary Table Indexer, 14 Pin Brush Drive Motor + Controller. Miniature Tube Single-Ended Applications. There used to be believe talk about not using Russian tubes and/or tubes with a spiral filament in the 410H phase inverter position because it could malfunction and cause damage. One may be forgiven for thinking the top tube works like a cathode follower. Re: Peavey Classic 30 Output Tube Filament Wiring « Reply #2 on: April 21, 2015, 12:16:13 PM » Thanks Matec. This stage will cleanly power headphones from 32 Ohm to 300 Ohm. It was easy to create a good-sounding amplifier. Fender amps made prior to 1963 carried this type of Bias-based Tremolo circuit - but it was labelled "Vibrato" on Fender amplifiers. cathode follower, vacuum tube rectification, C-L-C-R-C anode filtration, 3 inputs, 2 outputs. Goodsell 33 Custom Mark IV Guitar Amp — Review The popular saying “you can't judge a book by its cover” could be rewritten for guitarists as “you can't judge an amp by its tube complement. Drive, Hi/Lo Voice Switch, Treble, Mids, Bass and Master Volume. The stage is self-biased, so negative DC grid bias is created by raising the cathode voltage relative to ground via the 47Ω cathode resistor. This is the Blues Jr, combined with some of my custom pedals and of course, my Schecter Tempest Custom guitar. 4 x EL84 (6BQ5 or 7189A) Dimensions (W x H x D): 165 x 125 x 210 mm (main unit) < 5k Ohm (6SL7 Cathode follower) Frequency Response: 10Hz – 60kHz +/- 1dB (2V P. The plate voltage is about 320 Volts and the output stage is a classic single-ended cathode follower. The electrodes are connected inside the tube. Bootstrapping, grid-leak and input capacitor: Now we have set the upper triodes conditions we can work out what AC load it present to the lower triode. Note the difference. I'll keep a JJ in the cathode follower. The Fender Blues Junior uses two EL84 output tubes which are fixed biased as opposed to cathode biased. After you try it you will find LTP quite stiff in comparison: this amp was a rebuiild of a cathode biased LTP amp. Victory now introduces VC35 The Copper, a single-channel, 35-watt head loaded with four EL84 valves that deliver a wide range of timeless British-inspired pop, rock, and roots tones. If you change the cathode resistor to 560, then 1/(2*pi*R*C) is a pretty good estimate. A WE396 -DC-> 2 X 12S4A -> 813(T) Amp can sound great. 8 ohm Speaker Output. May 10, 2017 - Direct-Coupled 6V6 Cathode Follower Tube Amp Schematic. This is how this amp is supposed to sound. Many believe that a cathode follower (or emitter, or source follower) has very low distortion due to a 100% negative feedback. 18watt Technical Discussion. More complicated, was to make the right choice, and find the right tubes to complete this Preamp. For the non adjustable cooler bias mod: Mouser part nums. The Long-Tail Pair. A Bottlehead Badge is not included with your kit but you can add one, at our cost (+$8. The cathode follower operates with 100% negative (voltage) feedback, which makes it exceptionally linear and minimises the output resistance. An early Audion has maximum unregenerated voltage gain under 10. Until the valve warms up and starts to conduct it violates the maximum grid/cathode voltage by a long way and the valve can literally go "POOF". Released January 2007. This is by all means a "hats off" amplifier. JMI - Limited Edition The Original Joe Morgan Industries amp! The Morgan JMI is a limited edition 20-watt, cathode biased, EL84 all-tube amplifier in the style of the old British “top boost” design. The EL84 idea got me researching other EL84 amps, where I picked up the rest of the pieces that went into the Verberator. Morgan Jones' Valve Amplifiers has been widely recognised as the most complete guide to valve amplifier design, modification, analysis, construction and maintenance written for over 30 years. It consists of a double triode for both channels, cathode follower, vacuum tube rectification, C-L-C-R-C anode filtration, 3 inputs, 2 outputs. This means the AC load line nearly coincides with the DC load line, which can make it difficult to identify the DC operating point. 105: The cathode follower with active load. MVAmps presents the New Gemtone Series. Cin should be less than 20pF. Very fine sounding if tubed right. Of course, the 5687 draws 0. Posted on June 2, 2012 by t-geek. The original ECL86 triode and pentode sections provides both these things and works very well - unfortunately (to the best of my knowledge) ECL86 is not in current production. The Victory VC35 is finished in stunning metallic copper with a matching brown vinyl-covered 2x12 vertical speaker cab. The feminine "wife" of Lampizator. Single-channel, four EL84 power valves and a plethora of timeless British-inspired pop, rock and roots tones. The cathode follower. NOS JAN ECC83/12AX7s are recommended for this position. This appears to be due to the closer spacing of the spiral filament to the cathode. The bias set on each tube was, in effect, the bias on the corresponding modulator output triode. Of course, that circuit has the advantage (?) of using the current source tube as a cathode follower (SRPP) to get lower Zo. Stereo Integrated Amplifier, el84, galaxy, Integrated, mini, mini tube amp, vacuum tube, valve amp. Spiral filament tubes include the 12AX7LPS, 12AX7EH, Tung-Sol 12AX7, Mullard 12AX7 reissue, and JJ ECC83s/12AX7. The earlier circuit (PI 1) used a cathode-follower directly connected to the PI circuit to both set the DC level and buffer the signal. One 12AX7 provides two stages of gain, simple high-cut tone control. Tip 77 (September 2011) To CF or Not to CF (cathode follower), that was the question – building a 12B4 zero-gain DAC out to line input buffer stage – J. Although maybe for hi-fi. Of course, that circuit has the advantage (?) of using the current source tube as a cathode follower (SRPP) to get lower Zo. If the amps are built to. Because the AC cathode follower is normally used only as a transparent buffer for driving difficult loads, it makes sense to use a. 99) 1x BeePre 300B Preamplifier Kit. If fixed bias is to be used in the output tubes they must be driven by direct coupled cathode followers. Single ended. Basic Set of Five Universal Amp PCBs The original set of five Universal Amp PCBs: 1x Triode Input 1x Cathode Follower / EQ / Cathodyne 1x Long-Tailed Pair 1x Dual EL84 Output 1x Power Supply Components not included. Very fine sounding if tubed right. This tube is also fitted with and unusually large bulb, large plate and can be confused with a 50 at first glance. Applications of the RCA-7199 Triode-Pentode in High-Fidelity Audio Equipment. The cathode follower is not strictly necessary, as the driver tube is well capable of driving the output tube on its own. 6K/ 2W PA-20 CONVERSION Sheet 1 of 1 REVISION 2 Adam Alpern High Octane with Self-Split EL84 Output 2/21/2002 Baxandall Tone Stack C12 470pF 1 3 2 VR3 500K-A BASS VR5 1M-A MASTER R19 10K R20 180K R18 100K C14 330pF 3 2 C13 4. Speaking of Bob Pease, aka RAP and a long-time contributor for Electron Design magazine, I am a long-time fan of his. controls* exhibit a DC offset at the output, as do a number of cathode-follower preamp outputs, particularly at “turn-on”. I agree that the cathode follower 12BH7 is a must. There used to be believe talk about not using Russian tubes and/or tubes with a spiral filament in the 410H phase inverter position because it could malfunction and cause damage. This value was chosen to exceed the expected peak grid current draw for the original 211 design (20mA). Asymmetrical modulation modification with a cathode follower. Feedback in Cathode Followers. See more ideas about Valve amplifier, Vacuum tube and Circuit diagram. I also loved my quad of Marconi-Osram GEC KT88s in a Tim deParavicini. 022uF) par une OD 716p 0. For example, the 0. Jan 5, 2020 - Explore stevehutchings's board "Tube Amplifer" on Pinterest. The stage has a gain of 125, can produce 90V RMS (254V PP) output at 0. As an input buffer tube it is great. Good candidates are E182CC, 12BH7A, 5687 excellent in the VT25/VT25A push-pull, 6350, 6463 and 6840. What Is "Blocking" Distortion? General. GZ34 Rectifier Tube. I used the White cathode follower output configuration, with carefully calculated sensing resistor values, in order to get an optimal WCF with the lowest possible output impedance. cathode follower EL84 EL84 EL84 EL84 Dual Terror Power Amp This pair in use when switched to two output tubes. A good part like a V-cap produces a very transparent sound compared to a cathode follower or interstage transformer. Telefunken ECC803S (E83CC) In my opinion these are simply the best. There's also a NOS EF184 pentode valve in a cathode-follower configuration to drive the tone stack in the preamp. With the floating grid circuit this leakage current is reduced to about 10- 12 A. Fletcher-Cooke output stage. Spiral filament tubes do not work well in cathode follower circuits and are prone to failure. I've built a few amps that way and you'd be pressed to hear a difference between plate driven and cathode follower driven. Then we have a cathode follower pushing a tone stack. I've attached an image of how I think the elevation circuit is wired. The input stages are lifted from the Vox AC15 (EF86 pentode) and the Matchless Spitfire (parallel triodes), and the power section is pretty much the same as a Marshall 18-Watt. Cathode Followers were introduced in the 50s by Fender in their Tweet Series, those amps had a NFB (negative feedback) loop, but with fairly high on 56kOhms and so they need more signal to drive the power amp circuit - a cathode follower was needed, to prevent the signal drop because of a higher damping of the tonestack. I really like how it turned out. 4, 8, 16 ohm outputs. 6L6) Stereo Tube Amp. This tube is also fitted with and unusually large bulb, large plate and can be confused with a 50 at first glance. GZ34 Rectifier Tube. Because the AC cathode follower is normally used only as a transparent buffer for driving difficult loads, it makes sense to use a. Colour may vary. The JMI combines the best of early 60’s top boost style circuits with an additional gain stage. It depends on the type of an active device, bias, load, signal strength and signal source impedance. 72 volts between grid and cathode would still be needed for 1 volt at the output, so we would need 2. 7nF VR4 500K-A BASS C15 3. png 5E3-pcb_V1_separate_cathode. The gain of the the individual stages is as follows. There is half of ecc83 and slightly weaker el84) Triode is used as gain stage and pentode as follower. 7K screen dropper. 6AS7 mini-OTL Headphone Amplifier The output stage is also simple - one half of the 6AS7 is built as a cathode follower with enough current to drive a 32ohm headphone directly. The 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. Possible alternatives to EF86 are EF80 and EF184, although I do not know the typical RC stage component values off the top of my head for these tubes. As it turns out, some of the Chinese tubes have some construction differences that help them survive a Cathode Follower circuit better than many Russian tubes and more to the point to this thread sound better. 6K 3 0R 1 W Fixed Biased 6L6 2 7 0 K 2 7 0 K 4 7 0 2 w 4 7 0 2 w 1 Ohm 1 8 0 K 1 w 15K 1w 10uF +-10uF + 68K 5 0 K T r i m 39K High Voltage. There's also a NOS EF184 pentode valve in a cathode-follower configuration to drive the tone stack in the preamp. The μ-follower is a gain stage and cathode follower connected in such a way that it provides a CCS load to the gain stage, making it much more linear. 7 Tube Stereo Output Amplifier. 6AV5GA SET with 7F7 & 6SN7 input/driver. ECF80 seems to have a similar gm to ECF82 - it being an earlier, lower current version of same - with the added advantage that screen current is less than half that of the '82. Progress has resumed slowly with the design of an all tube cathode follower amp incorporating some of the technology developed during the development of the MiniTron. Released January 2007. They cascaded the Plexi's bright channel into the normal channel, added a pre-phase inverter master volume and cold biased "cold clipper" gain stage and tweaked the resulting. The tube data sheets that show IC means Internally Connected. 18/dez/2017 - Direct-Coupled 6V6 Cathode Follower Tube Amp Schematic Stay safe and healthy. Cab Dimensions – 18”W X 10”H X 9-1/2”D. Single-channel, four EL84 power valves and a plethora of timeless British-inspired pop, rock and roots tones. In order to optimize this well-known installation, I chose Mcap / Mundorf / Audyn Cap and Stiroflex capacitors. Output Impedance 1: < 2k Ohm (300B Anode direct) Output Impedance 2: < 5k Ohm (6SL7 Cathode follower) Frequency Response: 10Hz – 60kHz +/- 1dB (2V P-P). The driver tube will have the cathode at a very low potential, while the cathode of the cathode follower tube is going to see a relatively high potential, dictated by the voltage at the anode of the driver – depending on the particular tube used and a few other details, this will range between 100V and 160V DC – while the maximum allowed. Direct-Coupled 6V6 Cathode Follower Tube Amp Schematic See more. The two pairs of EL84 output valves are configured as push pull, cathode biased, class A power amplifiers. 5,00 € / Final. We have found that a triode-bas ed shunt regulator is better at handling this current fluctuation than the usual series regulator. If one wants to build the highest quality amplifier with no compromises this circuit might be used along with regulated screen grid voltages as in the 6L6. All DC coupled Aikido driven EL84 SE Amplifier. The downside is that the cathode follower is in series with the gain stage and consumes excess HT voltage because the (normally triode) cathode follower cannot swing to V a =0, and also because of the voltage dropped across R L. There’s also a NOS EF184 pentode valve in a cathode-follower configuration to drive the tone stack in the preamp. PLATE VOLTAGE – The voltage that is applied to the plate of a vacuum tube. Now to the AC30 power amp. 5mV, and not disturb measurements of more than 1Vrms. Single-channel, four EL84 power valves and a plethora of timeless British-inspired pop, rock and roots tones. I'm looking for ideas for an amp with the following tubes 12ax7 + ef86 + el84 or 6gw8 / 6mb8. 2x EL34 Power Tubes for roughly 50 Watts. The Sovtek 12AX7LPS is the same tube as the Groove Tubes 12AX7R2. Caution: Failure to follow this. Then we have a cathode follower pushing a tone stack. Instead of Dynaco transformers, Hammond 1608A audio output transformers and a Hammond 272HX power transformer were used. The EL84 / 6V6 PP Dynaco A-410 output transformer. Not terrible, but not good either. Also if you take the output from the mu of the cascode CCS you have an output impedance of 500 ohms, so no line or cathode follower driver …. TAD says the following about their new EL84 power tube: "The all new TAD EL84-STR tube combines the best of both worlds. For a partially bypassed cathode, the frequency at 1/(2*pi*R*C) is where the gain has risen a certain amount above the unbypassed gain. That means output from that tube is taken from cathode, so output impedance is low (cathode follower may be viewed as an amplification stage with hundred percents of feedback so it's voltage amplification factor is close to 1). The Marantz 7c circuit, with it's third cathode-follower stage, does not have this limitation. GENERAL ELECTRICAL Series Parallel Cathodeâ Coated Unipotential. Broskie's Aikido seemed to be a good, well-documented choice. jpg 5e3_Sean_Kilback_schematic_r3v. The Sovtek 12AX7LPS has a large plate format that gives a large soundstage with a lot of detail. namely the cathode follower is now moved to the top of the small signal pentode and arriving at some kind of mu-follower circuit. Progress has resumed slowly with the design of an all tube cathode follower amp incorporating some of the technology developed during the development of the MiniTron. This is actually the anode to cathode voltage, so the true cathode voltage will be 285 - 100 = 185V. Single-channel, four EL84 power valves and a plethora of timeless British-inspired pop, rock and roots tones. 68uf can be switched in. SRPP 6072A input stage, parallel cathode follower 5687 driver stage and fixed bias parallel 2A3 output stage. This might not be an ideal component for source follower service due to its relatively high R DS /low transconductance, but I had some on hand and it has a sufficient voltage rating (500V) for the application. Does the MAZ. i currently have a Tung-sol in V2, the sound of which i like, but i've been reading about different positions and i came across a lot of reports that this particular tube isn't suited for cathode follower positions. The tube data sheets that show IC means Internally Connected. This was one of the first amps Joe Morgan built, in his home garage, long before he ever considered starting an amp company. Text by Dave Hunter Data compiled by Alan Greenwood and Gil Hembree. So when an EL84 fails is it possible that it's filament will still be intact and feed voltage to the other series connected output tubes?. The anode is DC coupled into the grid of the cathode follower by a voltage divider which sets the 25V on the cathode. The problem is that if you turn on your amp from cold with the Standby off, that is with the amp active, the process can destroy a DC coupled cathode follower valve. Asymmetrical modulation modification with a cathode follower. This amplifier design uses a series-feedback voltage amplifier followed by a phase-splitter, (ECC81 dual triode) and two output valves (EL84 pentodes) with un-bypassed cathode resistors. 211 DC heated using TentLabs units. Very consistently made tube. 1uF pour une meilleure réponse dans les basses La triode V2a n’étant pas utilisée dans cet ampli, il est tentant d’implémenter un cathode follower pour “driver” le tone stack, comme décrit. As the AC15CC is a cathode biased amp, it does not require the bias to be set every time you change valves. Maybe the best triode in the world for building of a low impedance SRPP stage! Pentode. High gain, super low microphonics, and superb linearity with a three dimensional tone. 22uF Duelund CAST tinned-copper caps that I put in my MX110Z cathode follower positions were stunning right from the start, as they were when I tried them in my Altec A5's crossovers in the HF circuit. As Enzo points out, the only requirement is that the heater be more positive than the cathode. One output stage features its own cathode follower which adds a subtle widening effect and an extra dimension to the sound, even when operating in mono. Ok, so in search for a perfect second amp to my lazy j20, over the past few weeks I've been buying some smaller amps of each tube family to finally compare the tone and feel of the four main families. The Fender Blues Junior uses two EL84 output tubes which are fixed biased as opposed to cathode biased. With fixed grid bias on the EL84 also the bypass capacitor required in case of cathode bias can be ommited. It may also be used in some 1960s lead models as a simple phase inverter. i currently have a Tung-sol in V2, the sound of which i like, but i've been reading about different positions and i came across a lot of reports that this particular tube isn't suited for cathode follower positions. Released January 2007. So, after having a good experience with my Motorola EL84 SE, I decided to deconstruct the Mr. the ac-4 power amp utilizes an el84 cathode-biased output stage. It was easy to create a good-sounding amplifier. EL84 Amplifier with extras. A good part like a V-cap produces a very transparent sound compared to a cathode follower or interstage transformer. Rod ~ World Tube Company Mullard The Mullard 12AX7 / ECC83 is a Very Smooth Sounding tube. As long as you purchase a matched pair of EL84 valves, you can whack them in and rock away! The 12AX7’s don’t have to be matched or anything, although some people like using a 12AX7 with balanced halves for V2, the phase inverter. the ac-4 power amp utilizes an el84 cathode-biased output stage. I also have a stock jet city jca20H (LTP, fixed bias, cathode follower before tone controls, master volume, positive feedback a very different amp) and it's a lot louder than this one (even the cleans are quite loud with my stock telecaster); but I. Maybe the best triode in the world for building of a low impedance SRPP stage! Pentode. There is no NFB follower action Possibly an EL84 will do, or ECC99, but I would NOT use a paralleled 6SN7, 6CG7 etc. The DUAL 20 features Morgan's revolutionary Power Level control which is a big part of the magic of this amplifier. Cathode biased 6V6 tube amp build Sound demo starts at 3:10. The effective Rin with bootstrapped 330k is over 5M0. Premise Evolution also gained all new propriety standby auto circuit, that both save and prolonged the life of EL84 tubes. For a partially bypassed cathode, the frequency at 1/(2*pi*R*C) is where the gain has risen a certain amount above the unbypassed gain. 3nF 2 R25 1K/ 5W R10 470K V4 V4 V3 Electron Tube Basing 6 7 5 4 9 8 1 2. With a sensitivity of 101dB, our custom. The DC-coupled cathode follower represents a very light load. Push-Pull (PP) EL84 (6BQ5. Parallel Push-Pull 5687 sections using common cathode resistor bias. png 5E3_Ceriatone. a questo punto potrei optare per una EL84 per il cathode follower (ne ho un pò a disposizione). The former cathode follower section now has its input connected to a. It is a 12AX7 + PP Ultralinear EL84 circuit with full "Bells and Whistles". Transcendent Sound produces vacuum tube audio amplifier kits that utilize OTL (output transformerless) technology. The cathode follower relies on the tube’s transconductance to keep its output voltage in line with the input voltage. Of course, that circuit has the advantage (?) of using the current source tube as a cathode follower (SRPP) to get lower Zo. This was one of the first amps Joe Morgan built, in his home garage, long before he ever considered starting an amp company. 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. (The sheet-snip above says "Class AB", but the cathode current rises only 25%, which is a lot closer to A than to B. In the chats, THD is 0. 72, or only 0. The Sovtek 12AX7LPS has a large plate format that gives a large soundstage with a lot of detail. After about a half hour of "tube tasting" some 12AX7's I did end up trying a few different matched EL84 to see if any noticeable change occurred but I wasn't ready to give up on the pair of RCA EL84's that were in the amp when I bought it. Could be used to power simple single tube preamplifier and extreme balanced tube preamplifier with differential amplifier and 4x White Cathode followers created with 6N30P tubes. Dropped the voltages just a tad in PSU to get a sweeter spot for the EL84 and also added a IRF820 cathode follower to boost the signal to the power amp a bit. Like the Compact Series amp, this one uses a mix of fixed and cathode bias in full-power mode and is cathode biased in low power. Cin should be less than 20pF. 72 volts between grid and cathode would still be needed for 1 volt at the output, so we would need 2. The gain of the EL34 cathode followers is 0,94 times, being a cathode follower. Modification du tone stack, implementation d’un cathode follower en amont du TS J’ai remplacé la capa de basse (0. This circuit performed better than the tube current source I was playing with earlier (using 2 EL34 tubes), when taking the output off the plate of the lower tube. It uses EL84 valves, which were a UK design and make. The ATM-211's design is said to follow that of Air Tight's highly successful ATM-300 (300B tube, 8Wpc), the 211 output tube permitting higher power. Output TX 7k amorphous. Tube layout and replacement The Intruder uses four ECC83/12AX7 tubes and two 6BQ5/EL84 output tubes (or two EL34 tubes in the 30W or 50W version). So just for kicks I am going to build an amp that is a hair bigger in size but rather than using 6AK6's for the output tubes putting out 2-4W I am thinking of using 6V6's or maybe EL84's. By referencing the zener's votlage to the negative rail, it would track sags due to the imperfect regulation, and would keep the currents largely constant. Above, the interior of the completed piece (audio chassis). PLATE VOLTAGE – The voltage that is applied to the plate of a vacuum tube. They work, but are likely to fail sooner. Very important, that, in those days of import controls. For the audio rig i have VTL mb185s which are rated at 230 w/side running on 6550 tubes. Instead of the parallel 12AX7 for the cathode follower I used a 12BZ7 which is very close in performance to two 12AX7s in parallel. Re: Ceriatone 18W TMB Nirvana « Reply #5 on: November 01, 2013, 10:08:11 AM » You can also try the 12DW7 tube which is a 12AX7 on pins6-8 (cathode follower on the TMB/EF86) and a 12AU7 on pins 1-3 (2nd gain stage on the TMB/EF86). I photocopied mine (yellowed, brittle, ripped. Cathode Followers The poor cathode follower; it gets little respector too much. It uses EL84 valves, which were a UK design and make. Please practice hand-washing and social distancing, and check out our resources for adapting to these times. The cathode follower is not strictly necessary, as the driver tube is well capable of driving the output tube on its own. Basic Set of Five Universal Amp PCBs The original set of five Universal Amp PCBs: 1x Triode Input 1x Cathode Follower / EQ / Cathodyne 1x Long-Tailed Pair 1x Dual EL84 Output 1x Power Supply Components not included. Noise should be < 0. AIKIDO Cathode Follower 1 2 3. A combined input stage and driver drives the output valve, and a transformer matches the valve and the speaker system. Released January 2007. Circuit is 6sn7 voltage gain, the el84 cathode follower direct to 211 grid, in a similar fashion to Ongaku. 5W when properly loaded and biased. Useful for reverb or maybe a cathode follower in a guitar amp. See more ideas about Valve amplifier, Vacuum tube and Circuit diagram. In (b) , the bias resistances are replaced by their parallel equivalent Rg. Under these circumstances, it is a good idea to enter an arbitrarily low resistance for the AC load. 25% @ 1W) and response is 10 Hz to 44 kHz +/- 0. 6BQ5/EL84/SV83 Power Tube in Class-A Single Ended Configuration provides 5-7 watts of output power. The 6350 is used in VTL and Joule Electra gear). I decided to build this small single ended amplifier based on 6L6 vacuum tube using a classic three stage single ended design. Jim is not a fan of output transformer-less cathode follower circuits, as they have a trade-off between output impedance and stability. This particular detail appeared as a necessity while contemplating biasing methods for the output tube, since fixed bias requires the adoption of a grid resistor lower than 50k. transformers for headphone amplifiers We offer a range of headphone transformers for single ended drive and drive from an ac coupled cathode follower. I agree that the cathode follower 12BH7 is a must. Single ended. ) a tube that acts up in one position may work fine in another. 1954 to 1956 some amplifiers were designed with the (in-) famous cathode-follower as 2nd stage, and the tone control positioned behind it. I used the White cathode follower output configuration, with carefully calculated sensing resistor values, in order to get an optimal WCF with the lowest possible output impedance. I typically use Tung Sols in the first preamp stage because they have a warm sound. The name is logical because the cathode potential varies with and is almost equal to the input voltage. The original design was found at the HeadWize homepage and it was taken almost straight off with almost no changes to the amplifier design. The circuit and its equivalent are shown in Figure 24. I also wanted to develop a driver for an SE amp with a follower output stage, which would require a tube that can idle at 500V or more on the plate. Under these circumstances, it is a good idea to enter an arbitrarily low resistance for the AC load. The voltage drop across the screen resistors is negligible at idle, so we can assume the screen voltage is 320V relative to. So when an EL84 fails is it possible that it's filament will still be intact and feed voltage to the other series connected output tubes?. Designing 6922 Cathode Follower; 6922 Operating Point Limitations; 6922 Operating Point Parameters; 6922 Dynamic (AC) Parameters at Operating Point; Calculating Cathode Bias Resistor; Calculating Cathode Decoupling Capacitor; Designing EL84 Pentode Amplifier; Designing 6922 Cascode ; Power Supplies; Designing a Power Supply. After subtracting the tone stack loss the 12AX7 cathode follower imparts close to 25dB of extra gain versus the amp's normal channel. Now there is an exception, the 5751 was designed to have a mu of 70, and a plate resistance identical to a AX, the 5751 tube was specifically designed to be a lower-gain, plug-in replacement for the 12AX7. being a cathode follower to drive the passive Eq controls then to it’s master volume and finally the channel switcher. JMI - Limited Edition The Original Joe Morgan Industries amp! The Morgan JMI is a limited edition 20-watt, cathode biased, EL84 all-tube amplifier in the style of the old British “top boost” design. NOS JAN ECC83/12AX7s are recommended for this position. There are a few minor deviations from the original schematics. A combined input stage and driver drives the output valve, and a transformer matches the valve and the speaker system. There is half of ecc83 and slightly weaker el84) Triode is used as gain stage and pentode as follower. The VC35 uses a mix of fixed and cathode bias in full-power mode and is cathode biased in low power. This amplifier will produces up to 4 watt audio power for each output channel. They work, but are likely to fail sooner. 6AS7 mini-OTL Headphone Amplifier This was a small side-step project that I made to test a few ideas around power filtering and to try out the 6AS7 tube. 1965 Vox Pacemaker v-3 Preamp tubes: three Mullard ECC83 (12AX7) Output tubes: two Mullard EL84, cathode-biased, no negative feedback Rectifier: Mullard EZ81 Controls: Volume, Treble, Bass, Speed, …. Tube-swapping is a familiar gain and tone-shaping technique, and Bias Amp allows you to swap the input stage and cathode-follower (output) triode tubes for, in descending order of gain, a 12AX7, a 12AT7 or a 12AU7, giving you the option to experiment with nine basic gain configurations before you start playing with the ‘front panel’ gain. There is usually no collector load resistor, with the collector connected directly to the supply. Section 2, which is similar to one section of a 12AU7, is intended for cathode follower or phase-inverter service. The cathode follower. DIY All DC coupled EL84 SE Amplifier The two stages of the Aikido driver are DC coupled and I thought it would be nice to have the final stage DC coupled as well. Tip 77 (September 2011) To CF or Not to CF (cathode follower), that was the question – building a 12B4 zero-gain DAC out to line input buffer stage – J. My 5E3 Deluxe plugged into a 125V outlet has a B+1 voltage of 368, plate voltage of 360, plate-to-cathode voltage of 340, screen-to-cathode voltage of 300 and 20 volts. Even though 6L6 tube is used primary in guitar vacuum tube amplifiers, many manufacturers use this tube in audiophile designs. Much easier and in my system better sounding. The poor tube head will probably forsake…. 11/21/2018 Note : I've added a little negative bias to the grid of the EL84, which increased the modulated power and made this TX more linear. 18/dez/2017 - Direct-Coupled 6V6 Cathode Follower Tube Amp Schematic Stay safe and healthy. Loosely based on the 18 watt Marshall, it has been. 5K)to get the proper bias @ 20/25mA. For instance, Say. Three 12AX7 tubes are used, two "V1" for Right & Left, and "V2" in Cathode Follower. I used 2604 and AD825 (paired on adaptor) and liked them both a lot. makes the 7199 especially suit- able for use as a voltage amplifier and cathode follower, or a voltage amplifier and phase splitter (the phase splitter is a form of cathode follower). Fletcher-Cooke output stage. Note that if the output tubes share a common cathode resistor, you must divide the current reading by the number of tubes sharing the resistor. Here's a collection of Bias-modulating "Tremolo" circuits which I use for retro-fitting common class-AB guitar amplifiers, circuits which are mostly based around the high gain 12ax7 dual Triode. Please practice hand-washing and social distancing, and check out our resources for adapting to these times. Nonetheless, I found that the general characteristics of any given tube would carry over from one amp to the other. Possibly an EL84 will do, or ECC99, but I. A Bottlehead Badge is not included with your kit but you can add one, at our cost (+$8. As the AC15CC is a cathode biased amp, it does not require the bias to be set every time you change valves. Cathode Bias (Self Adjusting) Cathode bias amplifiers shouldn't require any adjustments and will work with a wide range of tube plate currents, as the circuit is "self adjusting". The Maz Jr. 5-Position_Cathode_Switch. Hi Bill I’ve done the following mod’s so far, Cream board Basic, TO20 Heyboer, Presence control, Recap Kit, and Cathode follower. This is a fine solution and probably the preferred method for a "super amp," but we're trying to keep things simple. Hopefully most of you have got a. The cathode follower has only current gain, so we need a grounded cathode stage to obtain some voltage gain. The price we pay for this is gain, which is slightly less than unity. Class A, EL 84 Power Tubes • All-Tube Signal Path. In the EL84 you can see that the cathode and suppressor grid are internally connected before going to pin 3. We chose the thickest glass option and heaviest construction like the Russian EL84M tube and sonically most promising cathode and plate option to meet and exceed the tonal quality of the JJ/Tesla EL84 tube. V3 provides the second half of the cathode follower circuit. For example, making Rg=10 megohms allows the use of this stage in a condenser microphone. A lot of this is down to the harmonics, generated by the cathode follower stage, that enrich the output signal. ( Current feedback ) Wonderful engineering. 015 Orange Drop. The complete contest submission. Also if you take the output from the mu of the cascode CCS you have an output impedance of 500 ohms, so no line or cathode follower driver …. The driver tube will have the cathode at a very low potential, while the cathode of the cathode follower tube is going to see a relatively high potential, dictated by the voltage at the anode of the driver – depending on the particular tube used and a few other details, this will range between 100V and 160V DC – while the maximum allowed. The Rib plate is also a very good quality tube. As an input buffer tube it is great. Alter the values of the components in the tone stack to tailor your sound. K-follower,. This Blues Junior has the Billm basic mods, cathode follower, presence, and sparkle controls, plus the Clean Boost. Typical operating conditions for two EL34 la (max. Followers 0. With a sensitivity of 101dB, our custom Voice of the World Gold Label 10 speakers make the most of every available Watt, and you’ll soon notice the extra clout on stage. The extra half of the 6BL7 regulates the directly coupled cathode follower. The new solid plate, triple getter Ruby KT88V-STR has excellent reliability, focused soundstage, and a wide linear frequency response. This stage will cleanly power headphones from 32 Ohm to 300 Ohm. cathode follower, then to a classic Marshall three band. Very hard to find, this tube is Vintage and Extra Rare! The ECC803S is a very low noise, special quality 12AX7, made with the old-style Telefunken German precision. These EL84-based class-A beauties are entirely hand-wired in the lauded point-to-point style, and deliver classic British chime, shimmer, and crunch, but with a certain modern clarity and fidelity and a bulletproof robustness relied on by countless pros. The reissue Mullard EL84 power output tube is another winner. 6P30B or 6P30B-R. and a pair of NOS EL84's. The SV83 is used in a few high-end and guitar amps, while the EF86 is used as a low-noise preamp in guitar amps and professional audio equipment. In the case of a cathode follower, all of the current does so; with parafeed it is a small portion, and with the current source loaded voltage amplifier a tiny portion. Od Двухтактный ламповый усилитель на EL84 Od diyAudio. Under these circumstances, it is a good idea to enter an arbitrarily low resistance for the AC load. jpg 5F8_Presence. Power tubes are a pair of EL84/ 6BQ5. For guitar players in need of a great overdriven tone in Vox amps the Mullard EL84 is a good bet. The 6SN7 driver tube is suitable for both cathode-follower and plate-follower circuits. The downside is that the cathode follower is in series with the gain stage and consumes excess HT voltage because the (normally triode) cathode follower cannot swing to V a =0, and also because of the voltage dropped across R L. Asymmetrical modulation modification with a cathode follower. The print below shows the TX with a modified RF output using an EL84. V2A/V2B drive & cathode-follower tone, Harma ECC83-Retro Cryo normal gain V3A/V3B "PI" driver & n/u JJ-ECC83S normal-gain V4 O/P (EL84) NOS Russian Elektronka 6n14n (cryllic for 6P14P) low-gain, low-anode-current. Up and down the saw-tooth This degree of paralleling with shared and individual supplies made for a tricky line-up. SE headphone amplifier with one input and a passive volume control comprised of a 6N2P (double triode) feeding a single EL84 (6P14P) per channel with linear power supply to deliver 0. 7nF VR4 500K-A BASS C15 3. The gain of the EL34 cathode followers is 0,94 times, being a cathode follower. One output stage features its own cathode follower which adds a subtle widening effect and an extra dimension to the sound, even when operating in mono. This page details the construction of an AX84 High Octane style amplifier: www. GENERAL ELECTRICAL Series Parallel Cathodeâ Coated Unipotential. This is actually the anode to cathode voltage, so the true cathode voltage will be 285 - 100 = 185V. Push-Pull (PP) EL84 (6BQ5. There is a project at HeadWize, too. png 5E3-pcb_V1_shared_cathode. The AC30 push-pull power amp includes four EL84 pentodes, two for each phase. In addition, it is possible to power small amplifiers for example: stereo EL84 SE Amp, or single channel EL84 PP Amp. The A2 driver is capable of sending the grid at least 40v positive, so peak power is just above 30w. Cin should be less than 20pF. Inside a tube’s glass enclosure, you have 1) a vacuum and 2) at least two electrodes (but often more, depending on what type of tube we’re talking about). [or the tweed deluxe with headroom, power and output tube distortion power and output tube distortion. ) This amplifier is also able, via a capacitor straight from the cathode and without inductive coupling, to drive my old Philips 800 ohms wide banwidth speakers, namely the AD 5038, also rare. The EL84 / 6V6 PP Dynaco A-410 output transformer. TUBES: Input-6N6P Rectifier-EZ81. 4 x EL84 (6BQ5 or 7189A) Dimensions (W x H x D): 165 x 125 x 210 mm (main unit) < 5k Ohm (6SL7 Cathode follower) Frequency Response: 10Hz – 60kHz +/- 1dB (2V P. There’s also a NOS EF184 pentode valve in a cathode-follower configuration to drive the tone stack in the preamp. Miniature Tube Single-Ended Applications. 022uF) par une OD 716p 0. If it starts working better than you are on the right track. And you needed to run. The voltage will settle at whatever bias is required to maintain the CCS current as idle current thru' the tube. Popular low power tubes were dual triodes (ECCnn, 12Ax7 series) plus the EF86 pentode, and power valves were mostly being beam tetrode and pentodes (EL84, EL34, KT88 / 6550, 6L6), in both. Here is where you get creative. But in fact a conventional follower may have a substantial distortion. In the EL84 you can see that the cathode and suppressor grid are internally connected before going to pin 3. If your amp has a particularly bad sounding "cutting in and out" kind of distortion (commonly referred to as "farting out"), it is likely suffering from what is known as "blocking" distortion (not the Radiotron Designer's Handbook definition of blocking, but the more esoteric Norman Crowhurst definition). "So, my next selection was the 300B in the Silver 300 with silver wiring and silver output transformers. A cathode follower (like Franco's last circuit) is likely your easiest solution. The 6AS7 was a hot candidate but was finally refused due to the high heater current it needed - the regulator couldn't take it (it is limited to 7A and with 2 x 6AS7 + 2 x 6SN7, 10A is needed to play safe). It is suitable for testing 6L6, EL34, 6550 and EL84 types. The power amp uses one 6CA4 rectifier and one EL34 output tube. The EL84 was refused due to my wishes to make a pure triode design. It's output feeds the tone stack and the treble pot feeds the phase splitter(V3). Cathode follower circuits are said to lend the tone a special flavor, as a number of classic guitar amps would go to show. This amplifier will produces up to 4 watt audio power for each output channel. I use them in my '70, '71' and '73 Hiwatt and Marshall guitar amps and even in my brand new Freidman plus my buddy's new Mesa. Billm proposes to use a 12DW7 (a 1/2 12AX7 and a 1/2 12AU7 for the cathode follower). A new page for this design will be created soon. I recommend the JJ EL84 or a 6BQ5. Incidentally, the. 12au7 Radio 12au7 Radio. Pastafarian deity The first time anyone sees a series regulated tube power supply, they start to question what they know about tubes. The Morgan JMI is a 20-watt, cathode biased, EL84 all-tube amplifier in the style of the old British "top boost" design. A combined input stage and driver drives the output valve, and a transformer matches the valve and the speaker system. For the non adjustable cooler bias mod: Mouser part nums. The Mini Block tube amplifiers use a 5751 in the driver position and the EL84 output circuit is biased into Class-A, ultra-linear operation. This is a custom tube amp I just finished up. Up and down the saw-tooth This degree of paralleling with shared and individual supplies made for a tricky line-up. For guitar players in need of a great overdriven tone in Vox amps the Mullard EL84 is a good bet. 0: 6U8, 2A3: 4: My first tube amplifier: Intended for use as a separate state to have around for radio use. One output stage features its own cathode follower which adds a subtle widening effect and an extra dimension to the sound, even when operating in mono. I am Jumping between Tung-sol 5881's and a THD yellow jacket with el84's that's right 84's with these this amp cooks. 00) Get a Bottlehead Cap (cotton twill in black), add to your order for just (+$15. Note how the output in this diagram is in a different place than what you've seen in amplification stages. This is the purpose of the other half of the 6CG7. NOS JAN ECC83/12AX7s are recommended for this position. If I had used triodes with high enough current (30mA or more), the plate voltage would have been, say, about 100V-120V. ECF80 seems to have a similar gm to ECF82 – it being an earlier, lower current version of same – with the added advantage that screen current is less than half that of the '82. Single-channel, four EL84 power valves and a plethora of timeless British-inspired pop, rock and roots tones. Output power is 5. Audio coupling capacitor C7 is not fitted, final audio stage Q6 and R9 are removed from the PCB. “VC35 The Copper has gone over so well that it just made sense to offer the Deluxe version. Bolted into one of Matchless rare exotic-wood cabs, they look awful sweet, too. The first amp built was a straight copy of the Audio Note Neiro. From there, a cathode follower provides a low impedance signal for the tone stack. 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. We're NOT trying to get "that valve sound" in this part of the circuit. io You are about to report the user "Timothy Cose",. The Lightning epitomizes the classic EL84 "British Sound". The μ-follower is a gain stage and cathode follower connected in such a way that it provides a CCS load to the gain stage, making it much more linear. If it starts working better than you are on the right track. such as a triode -cathode follower and final stage is best choise of amplifier. Most of the designs I've seen or simulated in SPICE exhibit way too much gain, and nearly all invert the signal. "The 300B is very linear but doesn't need drive current. Please practice hand-washing and social distancing, and check out our resources for adapting to these times. The guitar amp is insanely loud. Note that if the output tubes share a common cathode resistor, you must divide the current reading by the number of tubes sharing the resistor. Bias exceptions. I made some tests in the past ( I have a few of these beauties ) and the best driver was a 6C19Pi cathode follower choke loaded with a Hashimoto custom made one (50H/1. A low noise tube is not critical, however the heater-cathode insulation must be good quality. Audio Asylum Thread Printer. 5 Kohms (primary) and is set for 8 ohm speakers. ULTRA-LINEAR DISTRIBUTED LOAD HIGH-FIDELITY VACUUM TUBE AUDIO AMPLIFIERS * * * ULTRA-LINEAR OPERATION, also known as DISTRIBUTED LOAD OPERATION, is a term when applied to single-ended or push-pull vacuum tube audio amplifiers, that describes the particular output stage configuration whereby the Screen Grids (Grid 2) of Tetrodes, Pentodes or Beam Power Tubes are fed from a. Four Tungsol EL84 tubes per channel ensure enough energy to engage any speakers in a normal listening environment. 8 ohm Speaker Output. I think the GA-20RVT Minuteman is an excellent alternative to the very pricey black-face Fenders. web; books; video; audio; software; images; Toggle navigation. This is a jaw dropping experience. All DC coupled Aikido driven EL84 SE Amplifier. GrandMeister Deluxe 40 combines all-tube tones and smart control features in a supremely playable package! On top of its plethora of amazing sounds, every knob and switch setting on GrandMeister Deluxe 40 can be easily saved, stored and recalled at the touch of a button, and the studio-quality on-board effects settings are saved right along. hi guys, i'm waiting on 3 JJ ECC83's and a Tung-Sol reissue 12ax7 for my DSL100, as it's the best compromise for my preferred tone + (drug) budget. A combined input stage and driver drives the output valve, and a transformer matches the valve and the speaker system. It runs really hot, 325 volts on the plate, 110 mA cathode current. The warm tube glow of the Mullard EL84 tubes. to waste a tube doing a cathode follower to push a proper Marshall circuit, and yeah, I wanted to use the parts I had. EL84 Single Ended AmplifierD. The high-gain V1 pushes the normal-gain V2 into crunch on the drive channel. cathode follower EL84 EL84 EL84 EL84 Dual Terror Power Amp This pair in use when switched to two output tubes. The result would become the Super 17, Goodsell’s flagship, a dual-EL84 amp producing 17 watts which is now in its fourth iteration as the Mark IV. It controls the bias on all tubes, handles start up and shut down, has data logging. Well, the easiest solution would be a FET doing the same job. Cathode-bias is upset if current changes from idle to full output, which essentially means Class A, much less output power than possible in Class AB. This is how this amp is supposed to sound. It uses EL84 valves, which were a UK design and make. What others are saying. The result is an unbelievable clarity and realism that no other configuration can achieve. SPECIFICATION:. amplifiers or modulators. This means the AC load line nearly coincides with the DC load line, which can make it difficult to identify the DC operating point. 6*pi*R*C) is a better estimate for the cut-off frequency. The el84s are seeing 270v and biased with a 180 ohm resistor which according to weber's bias calculator is giving me 7 watts/ tube. Rod Elliott has a good explanation for you: ESP Amplifier Basics - How Audio Amps Work (Part 1) Now, pentode. Followers 0. There is no NFB follower action Possibly an EL84 will do, or ECC99, but I would NOT use a paralleled 6SN7, 6CG7 etc. controls* exhibit a DC offset at the output, as do a number of cathode-follower preamp outputs, particularly at “turn-on”. The 6L6 simple Single Ended audio amplifier. So the first thing I would do for the C5 is get rid of the AC coupled cathode follower, V1b. The headphone stage is a White Cathode Follower push-pull topology utilising the ECC99 and coupled to the load by 470µF capacitor, no. 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. The failure of a "cathode follower" tube will cause sound dropouts or signal loss. ECC81, EL84 (4) 2: Audio Amplifier: From November 1951 "Electronics" Magazine: Cathode Follower: 13. I really like how it turned out. The DC-coupled cathode follower represents a very light load. Re: Ceriatone 18W TMB Nirvana « Reply #5 on: November 01, 2013, 10:08:11 AM » You can also try the 12DW7 tube which is a 12AX7 on pins6-8 (cathode follower on the TMB/EF86) and a 12AU7 on pins 1-3 (2nd gain stage on the TMB/EF86). 020 cap is my two ceramic high voltage "death caps" that I removed while doing the 3-prong conversion. It runs really hot, 325 volts on the plate, 110 mA cathode current. Shopping for Cheap TIANCOOLKEI at Music KTV Electronic Store and more from amplifier diy,bass amplifier diy,tda7498 amplifier,vacuum tube preamplifier,tube preamplifier,marantz 7 on Aliexpress. Mullard 12AX7- Vintage Tube. Projects I Like & Follow. The Sovtek Long Plate Spiral is a great tube in either V1 or the Phase inverter socket. EL84 power tubes, GZ34 rectifier, three 12AX7s and a 12AU7. Grid stopper for cathode follower = good. Due to popular demand, Hallman Labs finally have a few sound clips of my amplifier. Terry Kilgore is hooking me up with some NOS 12AX7's for the first tube positions and the PI. is his best selling amp. What Is "Blocking" Distortion? General. My amplifier has a cathode follower output stage, an srpp stage for the preamp and a cathode follower for a buffer amp befor the bass/treble stage. with identical currents flowing through the two 100 k ohm resistors the voltages across them are identical, if the resistances are identical. 807 parallel Single Ended Amplifier. 12ax7 for cathode follower for MC240? Discussion in 'Audio Hardware' started by Abbagold, Feb 12, 2020.