The final design was also found at the HeadWise homepage, where it was used in a EL84-based headphone amplifier. The EL34, EL84, SV83 and EF86 are true pentodes. 015 Orange Drop. Set in late-1950s England, VC35 The Copper's sonic foundation has evolved into a true hand-made boutique valve amp of the 21st century. The guitar amp is insanely loud. Not so much a voltage amplifier. If Marshall, then this is your cathode follower stage for the tone circuits. 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. A new page for this design will be created soon. The gain of the the individual stages is as follows. 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. Peavey Electronics Corporation is an American company that designs, EL84 power tubes, and have spring reverb tanks. There’s also a NOS EF184 pentode valve in a cathode-follower configuration to drive the tone stack in the preamp. One tester is being manufactured today, the Maxi-Matcher. I wanted to try out a Sovtek 12AX7-LPS in V2 , but I've read that those shouldn't be used in a Cathode Follower spot. It's really nice sounding. Rod ~ World Tube Company Mullard The Mullard 12AX7 / ECC83 is a Very Smooth Sounding tube. V3 is the phase inverter. 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. EL84 max Pa is 12W. The result is an unbelievable clarity and realism that no other configuration can achieve. For the non adjustable cooler bias mod: Mouser part nums. April 2014. The Fender Blues Junior uses two EL84 output tubes which are fixed biased as opposed to cathode biased. The brightness is gone the EQ way more tweak-able. The first amp built was a straight copy of the Audio Note Neiro. Due to popular demand, Hallman Labs finally have a few sound clips of my amplifier. A Direct-Coupled Amplifier with Cathode Follower by Raymond H. Very important, that, in those days of import controls. It uses EL84 valves, which were a UK design and make. I use JJs in tone driver/cathode follower stages and tube effect loops because they can handle the high cathode voltage. The Ortofon SPU Classic GM MkII / Woody SPU tonearm / Intact Audio dual mono SUT combination and Soundsmith Zephyr Mk III / Schick tonearm / Soundsmith MMP3 Mk II were connected with Duelund DCA20GA and DCA16GA interconnects, respectively, to a vintage McIntosh MX110Z tuner-preamplifier (with Duelund CAST Sn-Cu caps in the cathode follower. Asymmetrical modulation modification with a cathode follower. In this case the modulator module PCB needs to be modified. One is used. 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. 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. 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. From there, a cathode follower provides a low impedance signal for the tone stack. It retains the. This preamp works great with a variety of poweramps!. 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. The 300B was a better selection because it works with lower plate voltages from 380 to 450V. It was originally designed for high-speed digital computers (IBM) and was manufactured using very high quality materials under rigid controls and underwent rigorous testing. 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. It is a 12AX7 + PP Ultralinear EL84 circuit with full "Bells and Whistles". heater bias needed for SRPP stage for protect cathode. Cathode-follower driven Bass, Mid and Treble tone controls allow you to shape your sound. A low noise tube is not critical, however the heater-cathode insulation must be good quality. This transmitter is completely done without transformers. 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. Love these tubes and will recommend them to anyone with an EL84 amp. You need another transformer for driving it as in the new Qvortrup Ongaku; or a DC-coupled cathode follower as in the original Kondo Ongaku. Then Sansui perfected tube amplifier technologies by the end of the 1960's with the 1000 / the 1000A. Cathode follower = classic tones. Output transformer is 4. 2012 I wanted to build a good headphone tube amplifier. Baby Huey PP EL84 amplifier. V3 provides the second half of the cathode follower circuit. Stay safe and healthy. 5,00 € / Final. The screen though sits much lower (283V) as the amp has a large 4. 0: 6AS7G(2) 3: 2A3 Single Ended cathode follower drive amplifier: What's with the background of this web page? Cathode Follower: 19. Incidentally, the. The DC-coupled cathode follower represents a very light load. 47uf cap switched in. V2 provides the second of your dirty channel gain stages, and the first half of the cathode follower circuit. To replace the cathode follower stage, I put in a source follower with a LND150 MOSFET. 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. 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. 109: The White. • EF86 preamp plus a cathode-follower tone stack • 12″ Celestion G12H30 Speaker • Patented HybridMASTER™ volume management • 5AR4 Tube Rectified • Front panel Power and Standby switches • 4 x EL84 power tubes, up to 35W • Reverb On/Off pedal included • Selectable 8 and 4 ohm speaker outputs. cathode follower, then to a classic Marshall three band. The Cathode Follower An amplifier with the anode as the common terminal is called a cathode follower. 211 DC heated using TentLabs units. 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. This is a custom tube amp I just finished up. The amp I was primarily using was an Aikido where the 6DJ8 is used in the cathode follower output stage. low wattage el34 guitar amp. The cathode follower has only current gain, so we need a grounded cathode stage to obtain some voltage gain. Because the tube is a triode the cathode current is identical to the plate current (not so for a pentode). If the amps are built to. 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. 2012 I wanted to build a good headphone tube amplifier. 5K)to get the proper bias @ 20/25mA. 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. Mercury Boutique™ Axiom® Hand-Wound Transformers. The result is an unbelievable clarity and realism that no other configuration can achieve. My favorite tube of all was a black plate CV5042 (of uncertain heritage) which is a military version of the 12BH7A but it was better than those. The ATM-211 operates in class-A with no overall negative feedback, and uses a direct-coupled cathode follower-driver, and a DC-driven heater filament that is claimed to eliminate hum. 01 Duelund CAST tinned-copper coupling caps when I. Peavey Electronics Corporation is an American company that designs, EL84 power tubes, and have spring reverb tanks. If you are unsure, it’s best to include C1, replacing the original ceramic cap with a polypropylene type of the same value (0. This Blues Junior has the Billm basic mods, cathode follower, presence, and sparkle controls, plus the Clean Boost. The Fender Blues Junior uses two EL84 output tubes which are fixed biased as opposed to cathode biased. The sonic penalties for doing so are very minimal. Love these tubes and will recommend them to anyone with an EL84 amp. since only the cathode-fed phase is a cathode-follower (insert "DUH!" sound here). Noise should be < 0. So the first thing I would do for the C5 is get rid of the AC coupled cathode follower, V1b. I have read not to use these el84 in cathode bias amps just like many new production tubes and 12ax7 made today also do not last a week in cathode follower positions in preamps ! That is common knowledge and cathode quality has been affected by time and well developed rare earth coatings not around any more. No distortion figures were quoted, and the damping was not very good (the output impedance was 23 Ohms) but the authors. Dismiss Visit. The Victory VC35 is finished in stunning metallic copper with a matching brown vinyl-covered 2x12 vertical speaker cab. The gain of EL84 will be 18, reduced to 0. Asymmetrical modulation modification with a cathode follower. png 5E3_deluxe_tweed_schem. 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). SKU: BEEP Categories: Kits, Preamplifier Kits. such as 6N1P and an EL84 for the output. Pins 1, 6 and 8 are not used on the EL84, so feel free to use them as extra solder-supports for caps and resistors. Released January 2007. Because the AC cathode follower is normally used only as a transparent buffer for driving difficult loads, it makes sense to use a. 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. Except in a cathode follower circuit, the output is always taken from this part of the tube. 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. blindjim, your last post hit on an important point controlling output and that would be amp design details. It is probably the fact of its oxide coated cathode that produces a soft glow when lights up. The EL34 is widely used in guitar and high-end amplifiers as the power output tube. Vintage Guitar is marking 25 years of publication with a year full of features. 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. The parts that I could use were the Jensen coupling capacitors, Jensen electrolytic capacitors, some 6DJ8s, EL34s, KT88s, 6L6s, ALPS potentiometer, RMG resistors, etc. See more ideas about Valve amplifier, Vacuum tube and Circuit diagram. About 12 dB of NFB would be the minimum amount of NFB. 5,00 € / Final. Anyway in the end I build Gary Pimm’s cascode CCS loaded 6BQ5 (EL84) stage. A valve amplifier or tube amplifier is a type of electronic amplifier that uses vacuum tubes to increase the amplitude or power of a signal. Tube noise control function, when the tube 845 or 300B make some noise, you can use noise control knob on the top panel to control the tube noise. Tone stack and Cathode Follower mod. 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. Tim's 12AU7 Tube Preamplifier Schematic. The gain of the EL34 cathode followers is 0,94 times, being a cathode follower. 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. rs Powered by Invision. Mar 24, 2018 - Direct-Coupled 6V6 Cathode Follower Tube Amp Schematic Stay safe and healthy. This amplifier's pre-amplification parts use cathode follower circuit in order to reduce the noise and get better SNR. The voltage drop across the screen resistors is negligible at idle, so we can assume the screen voltage is 320V relative to. Due to popular demand, Hallman Labs finally have a few sound clips of my amplifier. since only the cathode-fed phase is a cathode-follower (insert "DUH!" sound here). The complete contest submission. SoHo - 20 watt (2 x EL84) or 35 watt (4 x 7591), Tube rectified, EF86-12AX7 cathode follower. The electrodes are connected inside the tube. Text by Dave Hunter Data compiled by Alan Greenwood and Gil Hembree. The A2 driver is capable of sending the grid at least 40v positive, so peak power is just above 30w. 68uf can be switched in. Victory Amplification proudly announces VC35 The Copper, a 35-watt all-valve head in the popular Compact Series. The Marantz 7c circuit, with it's third cathode-follower stage, does not have this limitation. 3V filament current! In the final version of the amp my B+ was only 265V. There is no reason to believe speakers will stop getting better, since all kinds of new innovations in materials science are on the horizon, and there are. Tube stage 3 has two choices for cathode resistance: 820 and 3K3, and can have a 0. This transmitter is completely done without transformers. 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. 211 DC heated using TentLabs units. I chose this design for one reason : Wiring this tube as tetrode we achieve the greater possible amplification as a result of higher grid transconductance. The Victory VC35 is finished in stunning metallic copper with a matching brown vinyl-covered 2x12 vertical speaker cab. 4, 8, 16 ohm outputs. 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. This CF will act as constant current load to the pentode and will allow us to achieve high gain. 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. If you cannot get your own tube tester, speak to a service technician for his recommendations. If it starts working better than you are on the right track. This was one of the first amps Joe Morgan built, in his home garage, long before he ever considered starting an amp company. 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. The complete contest submission. My non technical explanation as to why a cathode follower does not sound good at the phono output is because the signal is still below 1 volt and the cathode follower being a 100% regenerative form of local feedback affects the purity of the signal. The solution to both of these problems is to go fixed biased and to use a MOSFET Source Follower or Tube Cathode follower, direct coupled to the output tube grids with the bias applied to the follower (gate/grid). It's called the cathode follower and it doesn't amplify sh!t, at least not in the voltage embiggening sense. Of course, that circuit has the advantage (?) of using the current source tube as a cathode follower (SRPP) to get lower Zo. The cathode follower relies on the tube’s transconductance to keep its output voltage in line with the input voltage. 18/dez/2017 - Direct-Coupled 6V6 Cathode Follower Tube Amp Schematic Stay safe and healthy. This was inserted in the boxed area of Figure 2. Three 12AX7 tubes are used, two "V1" for Right & Left, and "V2" in Cathode Follower. 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. Only one transformer is used for modulation. 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. Single-channel, four EL84 power valves and a plethora of timeless British-inspired pop, rock and roots tones. Chances are most readers had an instant word association response of "AC30" when they read "EL84 quartet," but the Goodsell 33 Custom Mark IV. "The 300B is very linear but doesn't need drive current. 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. Especially class a/b verses pure class a. How Vacuum Tubes Work by Eric Barbour [The Basics] - [Inside a Tube] - [Why are Tubes Still Used] - [Using Tubes]. The warm tube glow of the Mullard EL84 tubes. The gain of the the individual stages is as follows. Pirate radio AM transmitter with PF86 in oscillator, PCF80 in cathode follower and driver, PL 36 in driver and PL 509 / PL 519 in output stage. ) onto 11" X 17" pages so now I use the photocopies along with various Eico 666 & 667 data charts; I don't have to roll the brittle paper anymore. The authors use a simple push-pull cathode follower arrangement shown schematically in Fig. The voltage drop across the screen resistors is negligible at idle, so we can assume the screen voltage is 320V relative to. The A2 driver is capable of sending the. Where I do like the 6SN7 is as a driver tube for typical pentodes like the EL84, EL34, 6L6, 6V6 and the like. 9 in follower mode. gif 5E3_vs_Normal_Volume_Control. We have great stock of them, they have very low microphonics and have proved to be superbly well made and reliable. ) a tube that acts up in one position may work fine in another. The extra half of the 6BL7 regulates the directly coupled cathode follower. 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. Grid stopper for cathode follower = good. 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. 015 Orange Drop. 807 parallel Single Ended Amplifier. K-follower,. The JMI combines the best of early 60’s top boost style circuits with an additional gain stage. A low noise tube is not critical, however the heater-cathode insulation must be good quality. As an input buffer tube it is great. One is used. No distortion figures were quoted, and the damping was not very good (the output impedance was 23 Ohms) but the authors. 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. May 10, 2017 - Direct-Coupled 6V6 Cathode Follower Tube Amp Schematic. Speaking of Bob Pease, aka RAP and a long-time contributor for Electron Design magazine, I am a long-time fan of his. ” Example: the Euro Blue and Red models are based on the Bogner Ecstasy 20th Anniversary model, which is an amplifier with 6L6 tubes. My friend, Kale Brown, helped me out and played my guitar, while I did the recording (mostly on a Tascam DR-05). Besides the grounded cathode amplifier, there's another very common arrangement for a tube that you are sure to run across. Due to popular demand, Hallman Labs finally have a few sound clips of my amplifier. “VC35 The Copper has gone over so well that it just made sense to offer the Deluxe version. For example, making Rg=10 megohms allows the use of this stage in a condenser microphone. In this case an EL84 is used as CCS for the 2 X 12S4A and a J-Fet for WE396. 6L6 valves may be used in place of the KT61 if various circuit modifications are made (cathode bias resistor changed from 100 Ohms to 300 Ohms/3Watt, the associated bypass capacitor omitted, the first stage plate resistor increased to 330kOhm, and the resistor feeding the. Output from cathode follower is from cathode which will have Vdc at about +14Vdc, where Eg1 bias = 0V. Terry Kilgore is hooking me up with some NOS 12AX7's for the first tube positions and the PI. Dec 18, 2017 - Direct-Coupled 6V6 Cathode Follower Tube Amp Schematic. A nice clean self-split EL84 PP/UL inspired by the Compact Power Hi-Fi Amplifier. Mine seems way underbiased with a 91 ohm resistor (hot). Node A in Figure 3 is between R10 and pin 1 of 12AX7A in Figure 2. This Bachelor. If you build this one, you might consider cathode biasing it initially, and making it fixed-bias later - perhaps, as a switchable option. I learn about the existence of internal plate resistance (rP) , the degeneration of tetrodes and pentodes when used as cathode followers. The EL84 was refused due to my wishes to make a pure triode design. The solution to both of these problems is to go fixed biased and to use a MOSFET Source Follower or Tube Cathode follower, direct coupled to the output tube grids with the bias applied to the follower (gate/grid). This amplifier was conceived as an addition to his “man cave” which contained a formidable collection of speakers acquired from auctions and secondhand shops. Audio tube amplifiers: Cathode Follower: (PP) EL84 / 6V6 Dynaco A-410 output transformer schematic. 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. io You are about to report the user "Timothy Cose",. 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. 211 DC heated using TentLabs units. Liang's KT88 and use the components to build a new SE amplifier. 18watt Technical Discussion. The EL84 idea got me researching other EL84 amps, where I picked up the rest of the pieces that went into the Verberator. Higher voltages give more headroom and high end; lower voltages give more breakup and a “browner” tone. It's output feeds the tone stack and the treble pot feeds the phase splitter(V3). Power supply is common for followers and then divided for each triode. The Victory VC35 is finished in stunning metallic copper with a matching brown vinyl-covered 2x12 vertical speaker cab. 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". ) Using the 1 to 10 step up, this would result in a 10000 Ohm output impedance. Typical operating conditions for two EL34 la (max. All DC Coupled EL84 Single Ended Amplifier. 100: definitions. jpg 5F8_Presence. EL84 SEP with 5965 input. It would've been easier and cheaper to just put that 220k resistor between C9 and the volume pot and gotten rid of R7 and C13, so there must have been a reason, but I'm guessing it came after a few rounds of tweaking. Audio Asylum - Search of All Forums EL84 Cathode will sit at around +10 to +12 Volts, normal cathode biasing voltage. Much more scooped in the midrange than the Spitfire and Nighthawk, you will quickly see how well it sits in the mix against other instruments. 807 parallel Single Ended Amplifier. In the chats, THD is 0. The EL34 is a man for a man's job, OK. 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. For example, the 0. 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. For example, making Rg=10 megohms allows the use of this stage in a condenser microphone. Monterey - 22 watt (2 x 6V6), Monterey HP: 38 Watt (4 x 6V6), EF86-12AX7 cathode follower; formerly known as the Memphis. 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. 123kΩ is used here. The cathode follower has only current gain, so we need a grounded cathode stage to obtain some voltage gain. SoHo - 20 watt (2 x EL84) or 35 watt (4 x 7591), Tube rectified, EF86-12AX7 cathode follower. In this case the modulator module PCB needs to be modified. With fixed grid bias on the EL84 also the bypass capacitor required in case of cathode bias can be ommited. See more ideas about Valve amplifier, Vacuum tube and Circuit diagram. The output may be attached to a suitable plate-to-600-ohm transformer for driving a standard balanced line, or to a cathode follower for driving low-impedance unbalanced loads. The output valves are confusingly drawn as tetrodes; in the EL84 the suppressor grid is internally connected to the cathode, so presumably it was the. The Sovtek 12AX7LPS has a large plate format that gives a large soundstage with a lot of detail. I agree that the cathode follower 12BH7 is a must. Driven by two 12AX7's, one for the Input Stage and the other is a "cathode follower" for Tone. The authors use a simple push-pull cathode follower arrangement shown schematically in Fig. 12au7 Radio 12au7 Radio. We understand that some technicians recommend Ei or Preferred Series 7025 for this duty. SRPP 6072A input stage, parallel cathode follower 5687 driver stage and fixed bias parallel 2A3 output stage. The CCS limits the maximum current going through the cathode follower – a very good thing when using DC coupling. 2012 I wanted to build a good headphone tube amplifier. In the summer of 2002 I decided to build a pair of mono block parallel single ended DIY tube amps, using the 807 tube. A Direct-Coupled Amplifier with Cathode Follower by Raymond H. For the non adjustable cooler bias mod: Mouser part nums. to waste a tube doing a cathode follower to push a proper Marshall circuit, and yeah, I wanted to use the parts I had. Broskie's Aikido seemed to be a good, well-documented choice. Alter the values of the components in the tone stack to tailor your sound. The biggest change was made in the power supply. Classic Orange. The Tung Sol 12AX7 is warm and big musically. Very important, that, in those days of import controls. NFB is essential in this circuit, since Ra in enhanced triode mode is around 4 k ohms. com ,the Leading Trading Marketplace from China. (same cabinet as the SRPP) My "Klaus"**- linestage with one 6SN7 per channel, capacitor coupled, potentiometer between the stages, output catode follower, no additional nfb, sounds even better. The circuit and its equivalent are shown in Figure 24. Power tubes are a pair of EL84/ 6BQ5. The amp I was primarily using was an Aikido where the 6DJ8 is used in the cathode follower output stage. In Colby and Park amps, I use Tung Sol, Chinese, and JJ 12AX7 tubes, as well as the Sovtek 12AX7LPS. 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 preamp circuit in these blackface amps, and the tone stage in particular—which also evolved into the silverface amps of the late '60s and '70s—was an original creation from Leo Fender and co. with identical currents flowing through the two 100 k ohm resistors the voltages across them are identical, if the resistances are identical. This was one of the first amps Joe Morgan built, in his home garage, long before he ever considered starting an amp compa. I typically use Tung Sols in the first preamp stage because they have a warm sound. Released January 2007. A low noise tube is not critical, however the heater-cathode insulation must be good quality. 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, …. In addition, it is possible to power small amplifiers for example: stereo EL84 SE Amp, or single channel EL84 PP Amp. It's really nice sounding. 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. Gain, Treble, Middle, Bass, and Master Volume Controls. I saw this as a neat alternative to triode connected EL84 (same number of tubes). An emitter follower, or common collector, configuration usually has either a current source or resistor supplying current into the emitter. 109: The White. Phase Splitters In a push-pull amp, you need a phase splitter to produce the two identical but in phase opposition signals to drive the power tubes. such as 6N1P and an EL84 for the output. My guitar rig is a boutique 35 wt el84 class A rig. 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. More cathode follower stuff (I hope that I do not hear from Bob Pease's lawyer for using the word "stuff" in the title. ” Example: the Euro Blue and Red models are based on the Bogner Ecstasy 20th Anniversary model, which is an amplifier with 6L6 tubes. The Victory VC35 is finished in stunning metallic copper with a matching brown vinyl-covered 2x12 vertical speaker cab. 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). The guitar amp is insanely loud. NOS JAN ECC83/12AX7s are recommended for this position. Bruce Heran outlines the design and construction of monoblock Push-Pull EL84 (6BQ5) valve amplifiers. The EL84 drivers sound like Ken Gilbert's BAGA from Ampage, and while it's a great guitar amp, it doesn't stay clean enough for bass. Baby Huey PP EL84 amplifier. RRA 2A3 See more. Released January 2007. I'm looking for ideas for an amp with the following tubes 12ax7 + ef86 + el84 or 6gw8 / 6mb8. SoHo - 20 watt (2 x EL84) or 35 watt (4 x 7591), Tube rectified, EF86-12AX7 cathode follower. The preamp circuit in these blackface amps, and the tone stage in particular—which also evolved into the silverface amps of the late '60s and '70s—was an original creation from Leo Fender and co. 18watt Technical Discussion. 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 Ortofon SPU Classic GM MkII / Woody SPU tonearm / Intact Audio dual mono SUT combination and Soundsmith Zephyr Mk III / Schick tonearm / Soundsmith MMP3 Mk II were connected with Duelund DCA20GA and DCA16GA interconnects, respectively, to a vintage McIntosh MX110Z tuner-preamplifier (with Duelund CAST Sn-Cu caps in the cathode follower. Applications of the RCA-7199 Triode-Pentode in High-Fidelity Audio Equipment. All DC Coupled EL84 Single Ended Amplifier. 55) Posted by lovetube on 2005-01-26, 05:46:32 (220. rs Powered by Invision. The reissue Mullard EL34 is New Sensor's remake of the famous XF2 Mullard EL34 power tube. 12ax7 for cathode follower for MC240? Discussion in 'Audio Hardware' started by Abbagold, Feb 12, 2020. A low noise tube is not critical, however the heater-cathode insulation must be good quality. Mar 24, 2018 - Direct-Coupled 6V6 Cathode Follower Tube Amp Schematic Stay safe and healthy. I was thinking ef86>12ax7 cathode follower >tone stack> el84 Other idea is two channels ef86 and 12ax7 mixer tube being the triode part of 6gw8 / 6bm8. The Birth of the High Gain Amplifier 2203 Master Volume 100 Watt, 2204 50 Watt and JCM800 Lead Series Preamp. Otherwise figuring the heaters positive to the cathodes is just the heater voltage + the cathode voltage + the signal peaks. This signal gain calculator is to support my QUAD II Triode driver article but can be used to calculate the gain of any cathode coupled amplifier provided µ and r a for V 1 and V 2 are known for their operating condition ~ For the phase splitter it is assumed that V 2 grid is at signal ground and using a negative R k supply this means simply connected to ground. To get the amp up to the 30 watt (ok, 27) that Vox felt (quite rightly) was necessary to keep up with rock'n roll drummers, you needed four of these slim, light, cheap British valves. In (b) , the bias resistances are replaced by their parallel equivalent Rg. These have been converted to cathode follower design as an improvement over the original hummy WAD design. Better 12AT7s (notably, the Mullard CV4024, Mullard ECC81 or RCA 12AT7 s) will also improve the tone of. 015k capacitor. 5 Kohms (primary) and is set for 8 ohm speakers. It has a TO20 output transformer and the TP24 power transformer. 5-Position_Cathode_Switch. We understand that some technicians recommend Ei or Preferred Series 7025 for this duty. They are different. The brute-force solution is to design a driver with a very low source impedance and a very high current-drive capability, typically a cathode follower. In this case the modulator module PCB needs to be modified. OP-AMP - LM4562s. The results are pretty good for what. Chances are most readers had an instant word association response of "AC30" when they read "EL84 quartet," but the Goodsell 33 Custom Mark IV. Project 4 - an EL84 Amplifier build commissioned by a friend. 1k capacitor. If you change the cathode resistor to 2K, then 1/(0. Gemtone Jr 12 watt push pull EL84 based amp with a cathode follower Marshall style tonestack. in the 600 ohms headphone amp. Text by Dave Hunter Data compiled by Alan Greenwood and Gil Hembree. This is actually the anode to cathode voltage, so the true cathode voltage will be 285 - 100 = 185V. 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?. Now to the AC30 power amp. Depends on where the tube sits. This banner text can have markup. Then we have a cathode follower pushing a tone stack. 5-Position_Cathode_Switch. The effective Rin with bootstrapped 330k is over 5M0. The Marantz 7c circuit, with it's third cathode-follower stage, does not have this limitation. such as 6N1P and an EL84 for the output. SRPP 6072A input stage, parallel cathode follower 5687 driver stage and fixed bias parallel 2A3 output stage. What others are saying. The other cathode biased guitar amps I have seen with two EL84 have resistors from 120 to 150 ohm. I had the brief loan of a Shiit headphone amp that uses the 6DJ8 as a gain tube. 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. One is used. But if it was cathode follower, and the load voltage was in series with the input voltage, then 1. A Bottlehead Badge is not included with your kit but you can add one, at our cost (+$8. Fender amps made prior to 1963 carried this type of Bias-based Tremolo circuit - but it was labelled "Vibrato" on Fender amplifiers. Subtotal $1,399. Victory Amplification proudly announces VC35 The Copper, a 35-watt all-valve head in the popular Compact Series. All tubes follow the same basic principles. 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. The A318B on the other hand is a plate-follower NFB amplifier. 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. Much easier and in my system better sounding. Preamp tubes are cathode-biased (well, after the '50's anyway) but a big jump in plate resistance will put the tube out of bias range. This is actually the anode to cathode voltage, so the true cathode voltage will be 285 - 100 = 185V. Tube compliment for maximum clean headroom with cathode follower mod v1 12AY7, V2 12DW7, v3 12AT7; For the Tone Stack Mod: Mouser part nums 75-715P1200V0. About 12 dB of NFB would be the minimum amount of NFB. It is probably the fact of its oxide coated cathode that produces a soft glow when lights up. V2 is the driver and cathode follower for the tone controls. A Direct-Coupled Amplifier with Cathode Follower by Raymond H. Click on Bob's head for list of his recent articles. The Fender Blues Junior uses two EL84 output tubes which are fixed biased as opposed to cathode biased. In a grounded cathode amplifier. Power supply is common for followers and then divided for each triode. 15 Profiles 11 Profiles. This is my current project, 12BH7 Cathode Follower Driven 300B Single-Ended Power Amplifier - currently only photos are uploaded, but I will describe this project in details very soon. One component of the MiniTron is the cathode follower amplifier, which still has its own page. 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. 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. One is used. Preamp tubes are cathode-biased (well, after the '50's anyway) but a big jump in plate resistance will put the tube out of bias range. There’s also a NOS EF184 pentode valve in a cathode-follower con guration to drive the tone stack in the preamp. 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. Liang's KT88 and use the components to build a new SE amplifier. 6P30B or 6P30B-R. controls* exhibit a DC offset at the output, as do a number of cathode-follower preamp outputs, particularly at “turn-on”. The cathode resistor is replaced with two and signal is coupled from between them with one electrolytic and one foil cap. The two pairs of EL84 output valves are configured as push pull, cathode biased, class A power amplifiers. Although, the 6H30/6C45 amp uses the 6H30 as a cathode follower, direct coupled to the cathode of the 6C45. The few that don't invert usually. 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. Lucky you are to have the Tungsram equivalent to the E140, very well made tubes. Miniature Tube Single-Ended Applications. The DC-coupled cathode follower represents a very light load. TAD says the following about their new EL84 power tube: "The all new TAD EL84-STR tube combines the best of both worlds. This value was chosen to exceed the expected peak grid current draw for the original 211 design (20mA). 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. (The sheet-snip above says "Class AB", but the cathode current rises only 25%, which is a lot closer to A than to B. Many believe that a cathode follower (or emitter, or source follower) has very low distortion due to a 100% negative feedback. 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. The gain of EL84 will be 18, reduced to 0. Note how the output in this diagram is in a different place than what you've seen in amplification stages. Royal Albert-45 Watt (2xKT77), solid state or tube rectified, dual 12AX7. Premise Evolution its all about purity and musical potency. 022uF) par une OD 716p 0. Released January 2007. The feminine "wife" of Lampizator. The amp has a true plate voltage (-cathode voltage) of 318V. There is a paragraph about each if you look at my profile, here. Chances are most readers had an instant word association response of "AC30" when they read "EL84 quartet," but the Goodsell 33 Custom Mark IV. Love these tubes and will recommend them to anyone with an EL84 amp. The Fender Blues Junior uses two EL84 output tubes which are fixed biased as opposed to cathode biased. is the Swiss-Army Knife of amps. 9 in follower mode. Low to medium power valve amplifiers for frequencies below the microwaves were largely replaced by solid state amplifiers during the 1960s and 1970s. The EL84 idea got me researching other EL84 amps, where I picked up the rest of the pieces that went into the Verberator. Dual outputs (cathode follower and anode. 1k capacitor. 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). 5K)to get the proper bias @ 20/25mA. 75-715P600V0. The circuit and its equivalent are shown in Figure 24. 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. In addition, it is possible to power small amplifiers for example: stereo EL84 SE Amp, or single channel EL84 PP Amp. (The sheet-snip above says "Class AB", but the cathode current rises only 25%, which is a lot closer to A than to B. 1 bias of -1 volt. This Blues Junior has the Billm basic mods, cathode follower, presence, and sparkle controls, plus the Clean Boost. In the chats, THD is 0. The tube data sheets that show IC means Internally Connected. 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 extra power of the 12BH7 makes the difference. 7K screen dropper. May 10, 2017 - Direct-Coupled 6V6 Cathode Follower Tube Amp Schematic. Cathode follower = classic tones. 47uf cap switched in. 3 or 4 equal secondary windings are provided on some models to give flexibility in the driving circuit and the headphone impedance. It also supplies a near constant current flow shared between the two cathodes--as current increases through the upper cathode the current decreases through the lower and vice versa. The results are pretty good for what. What others are saying. Were we both wrong? The gain in CF mode would be 1/2. Here is where you get creative. The outputs from V3 drive the EL84 power valves V5 and V6 for the left side power stage. TUBES: Input-6N6P Rectifier-EZ81. Also changed the 2nd triode's cathode bias switch back to 1. It's really nice sounding. V2 provides the second of your dirty channel gain stages, and the first half of the cathode follower circuit. The A2 driver is capable of sending the grid at least 40v positive, so peak power is just above 30w. These have less clean headroom, so they'll distort at lower volumes, but the distortion is usually warm and smooth. I used it widely for shunt regulator applications and as a cathode follower to drive low impedance loads directly, e. Direct-Coupled 6V6 Cathode Follower Tube Amp Schematic EL84 se schematic sarris. That is an additional complication along with the negative regulated power supply. 0: 6U8, 2A3: 4: My first tube amplifier: Intended for use as a separate state to have around for radio use. Clips sound good - It's been so long since i heard a stock P1 that I forgot what they sound like. 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. 020 cap is my two ceramic high voltage "death caps" that I removed while doing the 3-prong conversion. 105: The cathode follower with active load. The choices for cathode resistance on the 2nd stage are 10K, 3K3, and 2K8. Released January 2007. Because the AC cathode follower is normally used only as a transparent buffer for driving difficult loads, it makes sense to use a. Jan 5, 2020 - Explore stevehutchings's board "Tube Amplifer" on Pinterest. This Blues Junior has the Billm basic mods, cathode follower, presence, and sparkle controls, plus the Clean Boost. The design has been updated to the 21st century with some player comforts that make the amplifier easier to use with any pedal board and at any venue. I recommend the JJ EL84 or a 6BQ5. such as a triode -cathode follower and final stage is best choise of amplifier. Noise should be < 0. During transmission, the same buffer drives the AF side of the balanced modulator, that is a low-impedance port. Driven by two 12AX7’s, one for the Input Stage and the other is a "cathode follower" for Tone. 6L6GC Author: RCA Subject: FP-2012-01-07 Created Date: 1/8/2012 12:17:39 AM. Is V2 a cathode follower in a JCM pre? They're all sovtek 12ax7s, wondering if that might cause the noise. The 6350 is a very high quality dual-triode. Liang's KT88 and use the components to build a new SE amplifier. The headphone stage is a White Cathode Follower push-pull topology utilising the ECC99 and coupled to the load by 470µF capacitor, no transformers are used. 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. I've been reading good things about TAD tubes. Saved from E188CC+EL84_SE_diagram3. Pin 1 of the 12AX7 in Figure 3 is attached to Z in Figure 2. Although, the 6H30/6C45 amp uses the 6H30 as a cathode follower, direct coupled to the cathode of the 6C45. Get a view of an entire thread on one page For Sale Ads. jpg 5e3_Sean_Kilback_schematic_r3v. The complete contest submission. This is where the vacuum tubes directly drive the loudspeaker with no intervening transformer. I have a feeling that the SV811-10 draws LESS grid current than the 211, but I have not confirmed this. Telefunken ECC803S (E83CC) In my opinion these are simply the best. EL84 max Pa is 12W. It would've been easier and cheaper to just put that 220k resistor between C9 and the volume pot and gotten rid of R7 and C13, so there must have been a reason, but I'm guessing it came after a few rounds of tweaking. Tone stack and Cathode Follower mod. 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. blindjim, your last post hit on an important point controlling output and that would be amp design details. The 100 kΩ resistor labeled R8 in Figure 3 is the same resistor as that labeled R10 in Figure 2. Please practice hand-washing and social distancing, and check out our resources for adapting to these times. The extra power of the 12BH7 makes the difference. But I like the sound. Because the AC cathode follower is normally used only as a transparent buffer for driving difficult loads, it makes sense to use a. This is possible because the grid is biased negatively compared to the cathode (the negative bias is what allows it to modulate electron flow). Tone stack and Cathode Follower mod. 10″ Eminence Ramrod speaker: Genz Benz Black Pearl. Noise should be < 0. 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. This is the Blues Jr, combined with some of my custom pedals and of course, my Schecter Tempest Custom guitar. With fixed grid bias on the EL84 also the bypass capacitor required in case of cathode bias can be ommited. cathode stabilised by four series-connected Zener diodes. Malva Rosa AMP2. 022uF bass cap in the TS by a 0. The parts that I could use were the Jensen coupling capacitors, Jensen electrolytic capacitors, some 6DJ8s, EL34s, KT88s, 6L6s, ALPS potentiometer, RMG resistors, etc. If you build this one, you might consider cathode biasing it initially, and making it fixed-bias later - perhaps, as a switchable option. EL34 & EL84: Marshall is known for using EL34's and EL84's in their heads. In the chats, THD is 0. Of course, the 5687 draws 0. Found 200 records in Search of Tube DIY Asylum. A combined input stage and driver drives the output valve, and a transformer matches the valve and the speaker system. This lead to his use of an output transformer in the Tuba design. 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. 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. 3V filament current! In the final version of the amp my B+ was only 265V. Preamp tubes are cathode-biased (well, after the '50's anyway) but a big jump in plate resistance will put the tube out of bias range. 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. 5mV, and not disturb measurements of more than 1Vrms. Cathode Follower R22 5. I also had an EL84 laying around so I ran some tests with it. ****OUT OF PRODUCTION***NLA****. Subtotal $1,399. See more ideas about Tube, Valve amplifier and Vacuum tube. 2x EL34 Power Tubes for roughly 50 Watts. 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. The design has been updated to the 21st century with some player comforts that make the amplifier easier to use with any pedal board and at any venue. In the EL84 you can see that the cathode and suppressor grid are internally connected before going to pin 3. A lot of this is down to the harmonics, generated by the cathode follower stage, that enrich the output signal. There is 35Vrms generated by V3 at its cathode 2k2 from g1 to 0V, this drives V5 KT88 grid g1. I use JJs in tone driver/cathode follower stages and tube effect loops because they can handle the high cathode voltage. It is a 12AX7 + PP Ultralinear EL84 circuit with full "Bells and Whistles". Some 12AT7s that will work just fine as phase inverters (V6) will crackle and hiss in this position. By Dick Olsher Click here to e-mail reviewer The single-ended (SE) tube amplifier renaissance that has taken shape and blossomed in the US over the past six years has introduced a new generation to the musical joys of SE drive. The receiver has a simple AGC circuit, that will be better described later. For instance, Say. It all started with my decision to use the less known tube 807, a tetrode whose features and sounds I was well aware of, from a specific DIY project (with one tube per channel wired in triode) made by Christos Spathopoulos. The name is logical because the cathode potential varies with and is almost equal to the input voltage. The A2 driver is capable of sending the grid at least 40v positive, so peak power is just above 30w. (same cabinet as the SRPP) My "Klaus"**- linestage with one 6SN7 per channel, capacitor coupled, potentiometer between the stages, output catode follower, no additional nfb, sounds even better. I had some problems with oscillations. Jan 5, 2020 - Explore stevehutchings's board "Tube Amplifer" on Pinterest. 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. Malva Rosa AMP2. 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. 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). The power amp uses one 6CA4 rectifier and one EL34 output tube. It also supplies a near constant current flow shared between the two cathodes--as current increases through the upper cathode the current decreases through the lower and vice versa. V2 is the driver and cathode follower for the tone controls. If it starts working better than you are on the right track. I used two 6 VA Hammond 229 flatpack power transformers, which are really intended for printed circuit board use, but I mounted them on a turret/eyelet board. Projects I Like & Follow. Output Impedance 1: < 2k Ohm (300B Anode direct) Output Impedance 2: < 5k Ohm (6SL7 Cathode follower) Frequency Response: 10Hz – 60kHz +/- 1dB (2V P-P). How Vacuum Tubes Work by Eric Barbour [The Basics] - [Inside a Tube] - [Why are Tubes Still Used] - [Using Tubes]. 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. 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 amp has a true plate voltage (-cathode voltage) of 318V. 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. They are wonderful examples of EL84 amps, which I prefer to EL34 amps. Push-Pull (PP) EL84 (6BQ5. 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. Cathode biased 6V6 tube amp build Sound demo starts at 3:10. All Tube, Single Ended, Class A, Cathode biased EL34 (10W RMS) Dual 12AX7 Preamp, (3) Gain Stages with Cathode Follower. V4 drives V7 and V8 for the right side power stage. 5mV, and not disturb measurements of more than 1Vrms. The complete contest submission. 15 Profiles 11 Profiles. In this case an EL84 is used as CCS for the 2 X 12S4A and a J-Fet for WE396. Due to popular demand, Hallman Labs finally have a few sound clips of my amplifier. 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. 0: 6AS7G(2) 3: 2A3 Single Ended cathode follower drive amplifier: What's with the background of this web page? Cathode Follower: 19. The first stage common cathode gain is 50, the second stage common cathode gain is 53, and the third stage buffer stage cathode follower gain is 0. 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. Preamp tubes are cathode-biased (well, after the '50's anyway) but a big jump in plate resistance will put the tube out of bias range. This was one of the first amps Joe Morgan built, in his home garage, long before he ever considered starting an amp compa. We understand that some technicians recommend Ei or Preferred Series 7025 for this duty. 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. It uses EL84 valves, which were a UK design and make. The failure of a "cathode follower" tube will cause sound dropouts or signal loss. A low noise tube is not critical, however the heater-cathode insulation must be good quality. Best regards. 211 DC heated using TentLabs units. 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. The A2 driver is capable of sending the grid at least 40v positive, so peak power is just above 30w. Instead of the parallel 12AX7 for the cathode follower I used a 12BZ7 which is very close in performance to two 12AX7s in parallel. Terry Kilgore is hooking me up with some NOS 12AX7's for the first tube positions and the PI. I've been reading good things about TAD tubes. As such it is unique in presenting the essentials of 'hollow-state' electronics and valve amp design for engineers and enthusiasts in the familiar context of current best practice in electronic design. My friend, Kale Brown, helped me out and played my guitar, while I did the recording (mostly on a Tascam DR-05). The cathode follower relies on the tube’s transconductance to keep its output voltage in line with the input voltage. [or the tweed deluxe with headroom, power and output tube distortion power and output tube distortion. Loosely based on the 18 watt Marshall, it has been. The headphone stage is a White Cathode Follower push-pull topology utilising the ECC99 and coupled to the load by 470µF capacitor, no. It may also be used in some 1960s lead models as a simple phase inverter. 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. 5W output per channel in triode mode without negative feedback. 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. For the non adjustable cooler bias mod: Mouser part nums.
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