Ef86 input stage

Ef86 input stage. 6V6 PP cathode biased. When I go to OD though it's really easy to get splatty distortion. I might try the zener diode on the Ef86 schematic premier amp some bass club version input values double check want mistakes corrected edited. The EF86 is of course the tube used in the u67. It's a fantastic tube for Dr. Byrith by connecting the EF86 as triode, was a request, and the easiest way to adapt existing 520s for less gain was to triode-connect the input EF86. At a high level, it is a balanced input MC phono with Lundahl LL9226XL MC step-up transformers, CCS loaded LED biased triode-strapped D3a first gain stage, all-in-one passive RIAA EQ, CCS loaded LED biased triode-strapped EF86 second To get enough gain for the 50V to 60Va. The warlike casework of the Vortexions is I could swear I saw a thread recently comparing the 6AU6 to the EF86, possibly as a way to get that EF86 "complexity" without the micrphonics and cost. One channel is built around an EF86 with a 5-way Bass Shape switch and the other an ECC83 with the addition of a Voice control for extra tonal flexibility. 2C 292 R. The F-6 Hommage EF86 Edition is integrated with two selectable inputs and volume control. 47 microphone pre-amplifier is a recreation of the original valve line amplifiers used in Abbey Road Studios’ heralded and rare EMI REDD. PV5 T2/2. Or you could add a resistor connecting C8 with R20 to build a voltage divider (which is similar to the shunted pot, just in a different place). Member. Due to the brilliant sound character of the EF86 those tubes were commonly used in many radios and RTR tape recorders in the early 60s. Stay tuned for the Mullard Stern Mic Amp Mixer circuit using the EF86 screened pentode valve, which will be our next upload. 264dB. Circa 1964. 7M that the recent Super Premium MuMetal shielded inputs and nickel & steel outputs set the stage. The second stage is nearly identical with the first and is direct coupled to the third stage which is a cathode follower. B450 schAcoustic 370 amp section schematic Acoustic amp backline should model notAcoustic control corporation guitar amplifiers. Component Choice These PCBs are designed to accept a variety of modern components. After working with the P K67 capsule we turned our attention to the EF86 as a microphone preamp. A 3-color LED indicator shows The JPS3 features an EF86 and EL84 tube regulated outboard high-voltage power supply which uniquely operates at 80Hz to provide superior low noise operation compared to typical power supplies which run at 60Hz. New! This is because the grid-to-cathode voltage swing for the LTP is only about half the input grid-to-ground voltage swing. An NOS 12AX7 I've also had a rethink of the EF86 channel, I think the AC cathode follower was over-complicating it and wasn't a good gain structure, so I've turned it into a conventional 12AY7 triode gain stage. but in my opinion you get more pentode characteristics out of the pentode tube when its not used as the first gain stage like it commonly is. MarcelvdG, that circuit has some nice tricks! I like the bootstrapped pair configuration with EF86 and ECC83 cathode follower. Another channel with an EF86. want to double check some valuesProwess amplifiers. LPU I, LPU II and LPU III family of Phono Pre-Amplifiers share similar tube input stage- a pair of EF86 pentode tubes. It is only those who do not have correctly designed pre-amp/driver stages that find differences using worn/low gain valves compared to new high gain valves. EF86 input stage. Thank you Eli D. EF86 (or Russian 3S3P-EV), ECC81/12AT7, 5842, 6SL7 come to mind. Thamks for the input. The schematic is from the book "Build our own Audio Valve Single-Ended (SE) EL34 Tube Amplifier Schematic with EF86 input stage. Are there any good octal pentodes for that purpose (don't want to This is the classic single-ended EL84 schematic from Mullard. diyaudioprojects. Probably some simple mods would need to be done to the input stage to make it more suitable for modern useage,in any case it will be a good exercise to bring it 'back to factory' specwise. Amp chassis includes quad 6CA7 fixed-bias PP output stage with catch diodes from anode to ground, and 10k grid stoppers. roadum. I've done a thing loosely based on a 6G3, with a switchable parallel/single V1 and EF86 and the tone stack recovery stage and a 5G9 type trem. Valve Want that same amp to do crystal clean chords from an ES335, 12 string or other hollow body electric, you need to tighten up the output stage a bit. The Svetlana EF86 is manufactured in the Svetlana factory in Russia, and is designed to be a direct replacement for any EF86 or 6267 type. Explore. TUBES. 3 to 25. Basic price is $3150—the review sample featured 5Y3 rectification, Audio Note copper-foil-in-oil caps, M6 EI grain-oriented–core power transformers, and a choke-filtered Back in the early 60s input levels were around 150 - 180mv. The arrangement went like this: EF86 > CF using 1/2 12AY7 > tone stack > volume control > gain stage using EF86 Input Stage PCB This PCB allows you to build an EF86 pentode stage with gain control and ValveWizard signature morph control (discussed in my book, section 2. DIY Audio Schematics Tube Linestage Preamplifiers. Here is the latest folly of it You can modify your input stage to match Blencowe's circuit by changing just a few parts. I tried building an amp with just a 5879 and it didn't have hardly any volume. Check Details Instead of cascading one of the input EF86's into another, maybe just make the 1MΩ isolation resistors smaller, say 470kΩ or 220kΩ. Playback/record jacks for Tape Recorder. ECC83 Special version of the above amp with an additional EL95 tube as high frequency oscillator tube for magnetic sound recordings and EM84 indicator tube. The input stage contains two EF86 miniature pentode tubes, each of which is capacitor-coupled to its own output tetrode tube, but only one of which (call it input tube No. Premier b-160 club bass. Check Details 1 EF86 in triode mode (or EF40, EF804s) About 33dB. The EF37A was also made with the classic shouldered shape of envelope. PU in to volume pot and mixed with MIC channel in to TONE pot and then to 6GW8 triode gain stage, and then to 6GW8 triode cathodyne PI. As jelle says, it mostly works like a gain control. Because those tubes tend to be microphonic when set up at maximum gain, it's sometimes This 2A3 Single-Ended Triode (SET) Tube Amplifier uses a EF86 input stage and a solid state power supply. You have to have one more gain stage to drive the 5879 tube. When I chain the two input stages together (EF86 into 12AX7) sometimes I get crazy oscillation feedback when the power amp section is switched in. Black gate VK in the cathode (can be left out) - complicated NFB loop (can be ammended) - DC-coupling sounds interesting I haven't heard the mullard 3. The amplifier section holds the six tubes. Rod says: "When you chain the EF86 into the 12ax7 it is a ton of gain, any little issue with But typically, EF86s are used as the input stage for guitar amps. I've been wanting use some of my triode/pentode tubes for something. It seems that the McIntosh phono stage has 40dB midband gain, and 4. azazello. 5" high. There were several different types so I wasn't really intending to release all the gerbers, but if you were interested in particular EF86 Tube Reviews: See reviews of the best EF86 preamp tubes. 1 drives input tube No. OUTPUT LEVEL LED. Top. Tone pot. 3 but to give a sense of horizon here are some options that give/promise excellent results using the magical ef86/el84 combo: - Triode-wire the output stage (if 1. You can get a lot of gain, but not a lot of drive current. The trouble is, the schematic in the catalog was designed to extract the maximum possible voltage gain from the EF86, for use in microphone preamps, tape recorder playback preamps, record player magnetic cartridge preamps, et cetera. The 5751 vacuum tube is a low I should have the schem for the Ef86 input stage around here somewhere ,I might have posted it here before . PV5 L2/2: SS: EF86. Typical EF86 input stage. Mine happen to be microphonic, though triode EF86 input stage. Bell pot. The Master Volume Multiple gain stages used today in most high gain amps use multiple stages of 12AX7 tubes. 75-1 mA per side will get you what you want. An EF86 was famously used as the input stage for the early Vox AC30s, but it acheived such high gain (about 200) and was used in The phono was designed around a triode-strapped D3a as the input tube with triode strapped EF86 as the second gain stage. Check Details. What if you took one out and replaced the socket with a 9-pin socket, put a !@AX7 in Non of this two ! Both proposed schematics have few crucial mistakes . The tubes comprise three 5751, two EF86 and one 12AU7. The first stage performs any required equalisation, and the second stage performs tone control and variable-slope high frequency filtering. 3V using a LT1085 voltage Vox used the EF86 in the input stage whereas Selmer used it in the tone gain recovery. 12AU7 Schmidt PI. The output from the selector switches now feed a 470nf capacitor (C34-C35 were 47nF) that is then connected to the volume control. 10kHz: -13dB. GIBSON EH 160 AMPLIFIER SCHEMATIC Service Manual download, schematics . Board covered with gold and special varnish for better sound. ECC83. Dual-Triode Power Output. (I would have expected more like 100K) and if it is correct then that input stage is going to have very low gain and you will need the 150 plus gain out of that second stage to drive the EF86 Input Stage. May provide some background information for your original question. Steane's Sound Systems S304. This interests me a lot. Acoustic g100t combo guitar amp sch service manual download, schematics Tube amp schematics, tube amp information, tube amp Type 6BR7, like the Mullard EF86, was carefully designed for low internal noise and, especially, for low internal hum pick-up from the 6. Both 4mV (51db gain) and 10mV (43dB gain) input sensitivity adaptors were available. Staubsauger. Try to get the PS voltages to 200V for the first stage (12AX7), 400 - 420V for the LTP stage (6SN7). Two 2-pin input locking sockets. A Quad II, original or Classic, is a class-A push-pull monophonic amp with only two active stages. The signal then goes into the first gain stage by being sent to the grid (pin 9) of the EF86 driver tubes. Green -> Yellow -> Red. Serial No. The subsequent loss of open-loop gain at the frequency extremes resulted in reduced feedback and thus additional distortion in the bass and treble. At a high level, it is a balanced input MC phono with Lundahl LL9226XL MC step-up transformers, CCS loaded LED biased triode-strapped D3a first gain stage, all-in-one passive RIAA EQ, CCS loaded LED biased triode-strapped EF86 second The other thought was about the EF86 Svetlana circuit with the high-Z input configuration for a piezobut I would not need the gain that circuit offersa hi-Z buffer like even a JFET would suffice, so just cross the piezo distraction off the list of questions! Unless there is an opinion that I missed about the EF86 mic stage (odds of a I have a Williamson octal chassis (6sn7-6sn7-el34x2) that I would like to change to a long tail phase splitter for comparison. Two input (MIC, PU) channel PA amplifier. Thanks guys. PV5 M1/3: SS: EF86. An EF86 input tube and 12AY7 output tube amplify the signal with 75 dB of max gain. Green -> Yellow -> Red . Very few triodes can do this in a single stage. Too much fun. Turning that pot will alter the DC bias . Coupling and output caps are Miflex KPCU-01. The 5687 is direct coupled to the 300B grid, and a fixed percentage of the required voltage is provided at this via R29/R30 from a potential divider at the power supply. 2A3 Single-Ended Triode (SET) Tube Amplifier Schematic. The phono stage will accept Executive summary: they have an EF86 stage, an 12AX7 stage, and a power tube stage (6BQ5). Dimensions: 17. EF86 Triode is 19K plate impedance at 3mA. Sign up. This circuit not like Quad II phono stage. It has now had a circuit roughed out, and all the suspect caps have been replaced. When I get out of work I'm gonna start going through my Wanted to share my tube phono stage that I recently finished, along with a vintage turntable overhaul to match. Before I put the valve in can someone tell me why the screen grid of the EF86 is returned to part of the subsequent ECC83 stage cathode bias network - see attached - instead of via a resistor etc to HT? The input signal transformer the signal voltage steps-up the signal by 1:7, which the EF86 then further amplifies before passing the signal to the anode-follower gain formed by the two 6DJ8/E88CC triodes in parallel. But there was some complicated design elements in the u67 so we had a challenge: Could we create an equivalent mic preamp to the u67 without breaking the bank? Hey it's a Pentode! Right out of I repo’d the gain pot between the EF86 input stage and the first stage of the 12AU7, also adding a 1/4″ switching jack immediately ahead of the pot so that medium impedance (nominal 10K ohm) signals could be ‘directly injected’ into the 12Au7 stages (ideal for adding a little bit of gain and/or crunch to drum machines and synths). Some use 6SL7. ef86 input. The Peavey is filled with VOS tubes, a 12at is subbed for the 12ax in V1, other than that stock. 5mA/V) = 67kΩ. The rear panel may be “somewhat spartan”, but it gets the job done. 2 with a portion of its reverse-phase output, attenuated Hi Guys, Has anyone built one of these? I have just finished one and it sounds great, basically just the EF86 channel from an AC30/4. The model circuit can be simplified to that of Fig. Log in. 6" wide by 11" deep and 2. The power amp was a P/P 6BQ5 set. 7: Gegentakt-Endstufen in RC-Kopplung mit Ausgangstransformator Resistance-Coupled Push-Pull Amplifier Stages Using Output Transformers 1955 - Heathkit PAM-1 preamp is introduced using the EF86 pentode input tube, bearing notable similarly to the Quad and other British preamps which also preferred the EF86 input. Check Hi, I'm thinking of converting my Hoso56 Amp into a two channel amp with paraphase PI instead of the LTPI. The new ST-70 implements a passive high-pass network, located after the input volume trimmers, to contour Quite correct. Ef86 schematic premier amp some bass club version input values double check want mistakes corrected edited5 amp heads you should know about Gibson eh amplifier ampAcoustic model So the fellow I'm building them for was running them into two things with lackluster gain results ONe was a DDA console with I believe 2k mic inputs and 10k line inputs. Joined 2003. TONE is a 6-way rotary selector adjusting the frequency response of the EF86 channel. Both tubes are CCS loaded and LED biased. Lots of other preamps use 6DJ8 variants. Also known as 6267, Z729, EF806, and EF806S. in a mic preamp input stage, the voltage swing is generally so small that distortion is rarely a major problem. We are seeking a voltage gain of 100, so the total plate load needs to be R = 100 / g m = 100V / (1. Here is the latest folly of it (dubbed '6H3A' heh-heh) with the James TS (which I put in a couple of months ago, and which I really like with this amp). I might try the zener diode on the The EF86 in the voltage-amplifying stage is used under conditions approaching those of starvation operation. While some might choose this mod because they perceive the sound of triodes to be different, the reason I I n the schematic extract above I have also included the Radio input switching to show how it goes directly to the volume control ~ unlike the TAPE and MIC and DISC inputs which use the EF86 amplifier stages and are responsible for much of the wiring between the back plate and the switch–bank and the bad cross–talk between inputs and channels L1/3 version for light sound only (one EF86 less). 5V4G rectifier. I also worked on a Gates Dualux board with the EF86 version. 2019-12-11 2:40 am #7 2019-12-11 2:40 am #7 There is I built an MM phono preamplifier with EF86 input valves some seven years ago. If we set R L = 82kΩ, The Adagio Phono Stage is an amplifier contained inside two separate chassis. 4. Siemens Haufe T Super Premium MuMetal shielded inputs and nickel & steel outputs set the stage. EF86 mixer stage. The first stage voltage amplifier is essentially identical to an example in a Philips EF86 data sheet, which has a voltage gain of 188. I think it was either on 18Watt or Hoffman, but now I can't find it. Two 4-pin speaker output sockets. kedsinger Occasional poster Posts: 340 Joined: Mon May 14, 2007 8:00 am Location: RI. Ef86 electro vide lampe harmonix vendu unitéAmplifier pre circuit input selector Ceriatoneusa manuals and layout diagramsA low cost valve amplifier. Ferguson PF163 PT and 8kPP OT. Not a screaming SLO lead overdrive type The input pentode circuitry for the VOX AC15 and other similar guitar amps was lifted straight from the back of a tube catalog. I think I'm going to have to monkey with that stage to cut the gain down. 5 dB. Arquitetura. Max. 8. Because channel mixing can't be done with the two inputs of the LTPI anymore I have two flip the phase of either the EF86 or the other channel before they meet each other at the paraphase gain stage. Siemens Haufe T-41: 1 EF86 in triode mode (or EF40, EF804s) About 38dB. input voltage 350mV. The Mullard circuit effin' SCREAMS when a strong enough signal smacks that ef86. Pinterest. It needs another gain stage before or after it to work. For more information about tube based power supplies, see the article Power Supply Design for Vacuum Tube Amplifiers. They are slightly darker sounding than many other Historical fact #1: VOX guitar amps with an EF86 pentode front-end were only sold for a few years, then the pentode was ripped out, and replaced by triodes. Each channel of the pre-amplifier is made up of two stages, and each stage uses a Mullard high-gain The impedance at each input includes the grid impedance of the EF86 modified by the feedback components as well as by the impedance of the The EF86 stage will have a gain of 150 or more. want to double check some values. At the time, it wasn't uncommon to order two sleeves of EF86's and 5879's at a time, since the quiet tubes went in the preamps and the others went elsewhere Ef86 schematic premier amp some bass club version input values double check want mistakes corrected edited. Dave Hunter explains all you need to know about output and preamp tubes: which models are good for different types of amps, how they affect sound, their price range, and other important factors. Input directly from CD player. That will pump up the signal going into the 2nd EF86 considerably. Tuner adjust. That has more gain than the standard plexi or jumpered inputs with nice bite but without the full saturation of the JCM 800 style 3-stage. A well designed pre-amp/driver stage with good negative feedback will make any, within tolerance, EF86 sound similar. The schematic is from the book "Build our own Audio Valve Amplifiers by Rainer zur Linde. The idea of their circuit design was borrowed from the input stage of early Reel to Reel RIAA EQ is passive, an EF86 pentode tube is used for each channel's input stage, a 6N6P dual-triode for the output stage, and there's no overall loop negative feedback. I did not check higher input signal levels. 5 watts is enough for you, no NFB; 270V@ 35mA sounds great EL34 x 4 (your choice) 6SN7 or ECC82 x 2 (Again your choice) EF86 x 2 if you are looking at Pentode input (my preference) Or 6SL7 or ECC83 if going for Triode input (sound very fine indeed) 8 pin octal valve base: 4 for EL34’s 2 for 6SN7’s 2 for 6SL7’s (need just one if sharing the 6SL7 between the channels) Then you will need OPT with a primary Ra of between 5k to The award-winning Artisan 30 in a head format. "As used in the DC-30 - and the Vox AC15 (and briefly, the early AC30) that inspired it - an EF86 pentode preamp tube helps Wanted to share my tube phono stage that I recently finished, along with a vintage turntable overhaul to match. One of these days I'm going to really make an effort at an Octal tube pre-amp. uk. Visit. want to double check some values Acoustic section. Slightly increased bass response. c. . Because those tubes tend to be microphonic when set up at maximum gain, it's sometimes advertised to half the available gain and/or drive it with a 12ax7 triode previously. The power supply is solid state. 2k inputs Was checking manuals online for both of them. This 2A3 Single-Ended Triode (SET) Tube Amplifier uses a EF86 input stage and a solid state power supply. You would have to talk with the original designers, but an EF86 can easily drive a signal through a simple tone control and high-cut filter into the output section The circuit uses and EF86 input stage. 8 = 64 V/V in the stage driving the 300B. The output is a AOT1N60 FET buffer with a constant current sink on the source. There is a very little of hum, noise, and distortion (for my ear, may be no for others). Input stage looks exactly like example for AF amp in Philips datasheet for EF86, but i can't find nothing similar for E180F. Phono preamplifier with separate power supply. Therefore, without the attendant adjustments this move will also require to the NFB and HF compensation networks, sensitivity will remain the same, but measured Ef86 inputEf86 input stage typical stages amplification audio quality high Vox ac15 ef86 preamp pentode circuit data amplifier voltage amp identical essentially philips gain example sheet which hasEf86 tmb 18 watt build. Dedicated XLR input connectors for sending audio 'out-of-the-box' without fear of phantom The line stage is also a complementary-symmetry J-FET. 13)! This allows you to morph the characteristics between pentode The input signal level is way too low to overdrive the stage and the tiny bit of harmonic distortion produced by the pentode gain stage is likely quite inaudible. An EF86 was famously used as the input stage for the early Vox AC30s, but it acheived such high gain (about 200) and was used in such a sensitive position that microphonincs was a major problem. Half wonder if the first step towards making these into a typical hifi amp wouldn't be to inject signal at the grid of the last EF86 and bypass the two gain stages upstream of it. All the noise generated in the first stage above 2122Hz will then be amplified by the full 1kHz gain of the phono stage, Over the audio-frequency band, the EF86 in pentode mode has an equivalent input noise voltage of around 2uV, which would be an R eq of 12k ohms! Input type: 1 MM input, 1 MC input (Z>47K), 4 line inputs: Bandwidth: 20 Hz to 50 KHz (line stage) @-3dB: Number of blocks: 2 (separated power supply) Tubes list: ECC88 X 2 ECC83 X 6 EF86 X 1 EL84 X 1: Dimensions: 1 MM and 1 MC input the JP80MC will allow you to connect any analog sources you might want to use. circa 1952. In addition, a global negative feedback loop extends from the two A tube regulated power supply, consisting of both an EL84 and EF86 tube, ensures absolute stability of this unit under all playback conditions. Although used in circuits such as tape recorder input stages and There are many references to the advantages of wiring the EF86 as a triode in the first stage of the Mullard 5-10 and I want to do this in a new build I but was confused by the relatively complex negative feedback network and its relationship to the cathode of the EF86. Good sound with sensitive preamps. Check This valve was employed in the input stage of high quality audio amplifiers for many decades. 0 x Top. Post by kedsinger » Thu Jan 03, 2008 10:21 pm. ). If we rearrange the placement of the screen-shunting capacitor, as in the following Third, the design of the two stages is deliberately engineered such that, the harmonic distortion produced by the EF86 is at least partially cancelled by an equal and opposite amount in the ECC88 (I cannot rememeber right now which harmonics this applies to but the original EMI description of this is available on line). Designed as a central component to the EMI REDD. Articles Contents Page The designs I looked at use EF86 pentodes, teh Mullard uses the EF86 in "pentode-mode" and some of the others have the EF86 wired in "triode-mode". After this Then calculate the equivalent G m of this input stage at common-mode input voltage for which only one of the input pairs or both of them are working, for input devices sized W/L NMOS = 50μ/2μ, W/L PMOS = 175μ/2μ and operated with tail currents I R1 = I R2 = 40μA from sources with the saturation voltage V Dsat = 0. VOLUME sets the overall volume and gain of the EF86 channel of the amp. Let's say you had a 1:5 - 1:10 or whatever high How about using an IRF820 as V1, with: - a 100k resistor between drain and power supply - a (1k5, xxuF) pair between the source and the ground as the Mosfet folies document suggests that the MOSFET can be substituted to a triode ; and if so: - what about EF86 input stage. This is the only other 6GH8 phono amp I've ever seen. OTL tube amp amplifier production : Vacuum-Tube Valves Circuits. if the guitar run clean or boosted and bypass the ecc40 works very well strong loud output, if the guitar is input to ecc40 i get Classical circuit design: EF86 input stage ,powerful low impedance triode output stage (el84) ,paper in oil siemens output capacitors, allen bradley and tantalum resistors , audionote and black gate electrolitic capacitors. In the end, it might prove more satisfactory to maintain a common cathode configuration at the output INPUT JACK GROUND BUS: preamp cathodes tone controls tremolo oscillator preamp filter caps TRANSFORMER GROUND LUG: center taps first stage filter caps mains earth I know its hard to really diagnose anything over the internet, but do those voltages, and that ground plan seem ok to you? Is the loud popping noise at the ef86 plate a problem? Logged If we bias the input stage with the same tail current as that of the model the input stage will have the same transconductance G m as that of the model, under the condition of equal type of transistors and same current densities as those of the model . 51 recording consoles circa 1959-1968. There you can use that Non of this two ! Both proposed schematics have few crucial mistakes . Schematics g20 preampSchematics amplifier amp transistor amplifiers akai ab class transistors bipolar complementary series these final Fender stage-100 160 sch service manual download, schematics, eepromPremier b-160 club bass amp. Since the only difference between both is in the EF86, this would mean that the gain of the EF86 stage is reduced by a factor 4. I use them in input stages of vintage amps where they perform fine. As far as I know it's discontinued as he has chosen to focus on DAC orders instead. Many specimens simply couldn't handle the speaker vibrations, so it was replaced with a trusty ECC83 in later models. The Problem: One problem I know a lot of DIYers have is trying to turn an idea into a physical reality. 5mV phono input sensitivity, with a nominal 0. Mic step-up transformer to EF86 gain stage and output volume pot. Each channel of the pre-amplifier is made up of two stages, and each stage uses a Mullard high-gain pentode, type EF86. ) For new builds I find more justification in keeping the EF86 stage as pentode as originally, with rather a lower µ tube as driver/phase inverter, say ECC82 The classic Mullard 5-10 (without tone controls) has an input sensitivity of 40 mV for 11W output with 26 dB feedback (according to the Mullard book). Although this is provided on each PCB you should only need to do it once, normally on the input stage PCB. I found several examples, one of The preamp is designed to take a 5mV input from a MM cartridge, but the Denon only produces about 1. 2x 6N8 MIC amps, 6SN7 mixer. A further George, the input will have exactly the same impedances as the EF86 preamps the unit emulates. These therefore are both high impedance but you can connect units with a low output impedance to them, such as the H & C These features made it the standard 1960s choice for the input stage of sensitive hi-fi systems, displacing type EF37A which was the previous (British) favourite for this application. Its design is low noise and anti-microphonic and was developed from If the input stage has another stage following it, and your source doesn't mind some input capacitance, a 12AX7 run at 0. High-stability, cracked-carbon resistors are used in the I've done a thing loosely based on a 6G3, with a switchable parallel/single V1 and EF86 and the tone stack recovery stage and a 5G9 type trem. This introduces a major side effects and shortcomings. By this I mean with a plate resistor that high you are running close to starvation mode. =C= logo Svetlana. Acoustic schematic schematics elektrotanyaAcoustic g60t sch service manual download, schematics, eeprom, repair Vm electronicsFender stage sch 2nd preview. I'm really enjoying all the input on this subject. It appears that most Mullard circuits use ef86 at the input stage. The EF86’s are pentodes, which allow for high frequency operation and a high gain (actual values will be discussed in the next section). Negative feedback from the output transformer is fed to the cathode of this Here are the transfer characteristics for an EF86 pentode, showing plate current versus grid voltage for several different screen voltages: which is the plate resistor R L in parallel with the 1MΩ volume control at the input to the next stage. Estimate the output impedance of this Another issue with both of them is that the EF86 stage generates a lot of noise. This exhibit was made by Mullard in Great Britain. Pickup vol pot. Check Details Pentode ef86 triode control screen variable blend infinitely quote make. The EF86 Tube . The EF86 is the standard early stage audio pre-amplifier valve. Turret board looks great but it's not cheap and isn't ideal for prototyping. ef86 input stage better suited for pedals addicts. If that doesn't solve the problems, you can put a trimpot between the output of the The RFT EF86 preamp tube is a durable tube with very low microphonics. This Jadis includes an MM and MC phono preamplifier that uses three ECC83 for MM The EF86 Tube . The input stage is a symmetrical SRPP. The Sovereign moves in a different direction. 10kHz: -12dB. All the equalisation takes place in the first stage, and is achieved by means of frequency-selective feedback between the anode and the grid of the first EF86. This may be an issue with a pentode like EF86 input tube, ECC83 inverter, power pentodes for output. The Svetlana EF86 features: • Low microphonics and low heater hum induction - suitable for input stages in high-gain microphone preamps, phono preamps or as a gain stage in condenser microphones The EF86 input stage does not need another gain stage. This is the classic single-ended EL84 schematic from Mullard. When I installed the tubes, I noticed Hammond transformers all around and a Hammond choke. Adding a ef86 preampEf86 photo by 6b4g High quality audio amplificationCircuit analysis of the vox ac15 pentode preamp and power amp. Then mixing the channels into a phase splitter and finally on to a class AB 6V6 PP output stage. No experience in preamps but don't see why they wouldn't perform well there too. The output You don't often see small-signal pentodes in guitar amps, where the ECC83/12AX7 is king. The MkII version features a new internal layout optimized for better isolation and input impedance selections between 48KΩ, 1KΩ, 300Ω, 100Ω for an optimal match with your cartridge. Mullard Single Ended (SE) EL84 Tube Amplifier Schematic The EF86 [1] is a high transconductance sharp cutoff pentode vacuum tube with Noval (B9A) It has a much higher stage gain than any triode, which makes it susceptible to microphony. The only thing missing was a tone pot to go with the Cut control, so I used the 18 watt tone pot circuit but unfortunately it seems to have a very limited tonal range and doesn't really do any more than the Cut control. It was used successfully as a pentode in a number of designs, both in Europe as the EF86 and in the States as 6267. From there, in addition to driving its corresponding output tube, input tube No. VOX, with the early AC30 is perhaps the best example. This increase is attributable mainly to the fact As with all Leak pre-amps, there are two gain stages each with shunt feedback. The feedback resistors and the compensation caps from the OPT secondary MAY need Try a EF86 in a plexi-style pre-amp, cathode follower, tone stack, etc. EF86 Input Stage. So your following stage's input impedance will have to be high. 7 Vout/Vin across the three EF86 tubes between an input voltage signal sinewave at 1KHz of 100 mVrms up to an input level of 500 mVrms. Single Ended Triode (SET) 2A3 Tube Amplifier Schematic from the book Build our own Audio Valve Amplifiers by Rainer zur Linde. So connect your input signal to the control grid and with a small voltage change it can "control" a fair amount of current going through the tube which is how you get amplification. A low level of hum and noise is essential in the input stage of an amplifier because high gain is required in this stage to provide a good signal-to-noise ratio and to compensate for the reduction in gain resulting from the use of negative feedback. Two EF86 valves are Opinions on the best input tube for a phono preamp with passive RIAA? I've used several integrated amps that use 12AX7A/7025 or 6EU7. So I need a gain of 180/2. All working fine except the input stage, thought to be an EF86. I eventually used Gold Pin JJ ECC83S in both of the SRPP stages and half of a ECC81 (12AT7) for the cathode follower. At 65VRMS out, 3rd was the only significant harmonic at -62dB. We could draw a loadline like 30K, get 11K output impedance. P. The other side of the inverter is fed by a pretty standard Fender-type reverb which comes after that same input stage. Dedicated XLR input connectors for sending audio 'out-of-the-box' without fear of phantom Option: Changing the Input Stage to a Triode. The EF86 tends to be microphonic. Is there a simple way I can up the gain of the EF86 stage to Most of the amps with EF86 preamp pentode use this tube as input gain stage. CD players can produce almost 2volts grossly overloading an EF86 input stage. dorrisant Posts: 50 ohm microphone input, with Vol pot. From . Fender stage-100 160 sch service manual download, schematics, eeprom 16 likes, 0 comments - karel_mars on November 23, 2022: "Mars Companion preamp section: EF86 input stage and 6SN7GT phase inverter/driver. Guitar amp wiring diagramAcoustic schematic schematics g20 amp preamp acc links model manual service typepad Ef86 schematic premier amp some bass club version input Acoustic model 164 – the amp that should not be Premier b-160 club bass. 009: Stern Mullard Mixer, Valve Mic Preamplifier EF86 Pentode This is a detailed look at a 4 channel valve audio mixing unit, which uses EF86 screened pentode valves for the mic amp stage and an ECC83 valve for the radio and crystal pickup inputs. It now goes EF86 - James tone stack - volume - 1/2 12AY7 triode gain - That will work. It has rich trem. , then a second preamp tube for gain makeup. The interstage/driver is based on the musical and well known 6SN7 double triode. Can anyone give me a link? If not discuss! I just read Dave Hunter's article on the AC15 in Vintage Guitar, and I'm all hopped up to build a pentode The 86-special is very controllable in the clean stage. This would be bad for >10' cables or into modern 10K input power amps. The 1k:6r divider gives further reduction for hum-critical stages. 2018-07-19 5:45 pm #6 2018-07-19 5:45 I want to put it together as a test bed for some mods maybe the EF184 as one input stage into a 12xxx and use the other 12xxx triode as a second input. Lower R20 to 500K and use a 500K for the series resistor. I believe he was using the line inputs He was also trying an Orion antelope 32 that I believe has 11. Subscriber. I stopped using that preamp when a balance problem developed in the phono amp. ••• Because I don't follow rules well or pay attention to guitar tube amp dogma, I stuck a vintage Peavey Rockmaster 3 channel preamp with footswitch in front of the input. Interestingly, a small amount of pre-volume-control signal is also shunted into the negative feedback Anyhow, you could swap the output tubes for some 12B4's, or you could shunt the volume pot by putting a resistor (about equal to the pot resistance) in series with the pot's input. The issue will be bandwidth- the 12AX7 will have a rather high output impedance, and this will interact with the input capacitance of the next stage. 100Hz: +14dB. So, what should i do to replace EF86 Early Vox AC15s and AC30s used the EF86 but were phased out by the 60s. The wide glass tube envelope is 29 mm in diameter and, excluding the IO base pins, is 84 mm tall. This amp uses an EF86 pentode in this area of the circuit. I decoupled the cathodes with 220 uF and used an AC heater supply. EF86 was designed for just that sort of application, the input stage of a low-level audio amplifier. Selmer's design really sound great with a strat because it is a wide bandwidth crisp EF86 was designed for just that sort of application, the input stage of a low-level audio amplifier. Sam Your design is kind of like how they run the EF86 in the Mullard 5-20. but slightly noisier than some triodes at about 2 μV equivalent input noise to 10 kHz. “The tube can be used without special precaution against microphonic effects, in amplifiers in which the input voltage is greater than 10 millivolts, when the tube is mounted in the vicinity of a 5 watt loudspeaker with an efficiency of 5%” The VOX AC-4 is the There’s no warning indicator for phantom power, I presume to retain more of a vintage look, and the instrument input is routed straight into the first-stage EF86 valve in a similar configuration to a similar-period guitar amp like a 1957-vintage Selmer. Gain is sufficient at 45 dB for me to use a high Hi Guys, Has anyone built one of these? I have just finished one and it sounds great, basically just the EF86 channel from an AC30/4. And a high voltage adaption using 12AT7 was discussed here. The Svetlana EF86 features: • Low microphonics and low heater hum induction - suitable for input stages in high-gain microphone preamps, phono preamps or as a gain stage in condenser microphones In this amp I have used a 5687 parallel cathode follower V3/V4 as a knuckle duster for the EF86, it provides a low impedance drive to the 300B grid and buffers it from the delicate input stage. Oct 14, 2013 #2 yes, and it seems to work fine as long as your tubes aren't noisy or microphonic. Check Details (See some of the RIAA phono stages using pentodes as input tubes without audible hiss unless one puts one's ear next to the loudspeaker. THe valve wizard seems to suggest I recall having to hand select tubes for the input stage carefully. I can get SQ, gold pin E180F or normal version of EF184. if the guitar run clean or boosted and bypass the ecc40 works very well strong loud output, if the guitar is input to ecc40 i get the EF86 stage works great (all thanks to Merlin's generous web pages). The New Vintage Pentode! For applications in particularly sensitive functions such as V1 or input stage with combo amps, V1 in high-gain amps, tube microphones and phono preamps, we recommend using the Most of the amps with EF86 preamp pentode use this tube as input gain stage. The input stage of the LPU V employs the EF37A- the octal version of the superb sounding EF86, both of tubes that were emplpyed in the RTR tape recorders in the early 1960s, directly respsonsible for the superb analogue recordings ever created. Voltage Gain 45dB. U out max 50v p-p. org. Schematic is from Build your own Audio Valve Amplifiers by Rainer zur Linde. The circuit is EF86 input, passive RC RIAA with Siemens styrene capacitors, output with choke-loaded EL84s, EZ80 rectifier. Both enclosures measure 8. So well, I used the same EF86 on a 18W build that sounds fantastic. This circuit is under:, audio, vacuum tubes, OTL tube amp amplifier production l58787 6N5P the output impedance of 400 ohms low resistance tube used as a parallel push-pull, the output BTW, your inputs aren't going to give you the "hi/lo" if you wire them up the way they are in the schematic. The Jadis JPS3 features both a dedicated MM input using 3 x ECC83 tubes and an MC input using 2 x ECC88 and for voltage gain. EF86 input gain stage with Ef86 inputEf86 input stage typical stages amplification audio quality high Vox ac15 ef86 preamp pentode circuit data amplifier voltage amp identical essentially philips gain example sheet which hasEf86 tmb 18 watt build. (The lower gain designed in by a Mr. ) For power amplifier design, I myself prefer a pentode input stage followed by a 12BH7 or E182CC L. It feeds the passive equalization network. Shop. That can be done with a pot and series cap across the grid to ground resistor in a UNSET based output stage. 2024-02-15 10:27 am #10 2024-02-15 10:27 am #10 Merlinb said: I stopped selling them. A local negative feedback loop spans from the EF86's plate to the two combined 6DJ8 plates. 4Vrms, for driving the Quad II amplifier. Reactions: huggygood. Also, I generally dislike designs in which the driver overloads before the output stage. #tubeamps #tubeamplifier #marsamps #madeinsouthafrica #tube #stereophile" The input stage contains two EF86 miniature pentode tubes, each of which is capacitor-coupled to its own output tetrode tube, but only one of which (call it input tube No. Use this knowledge to experiment, to hold your own in tube debates with fellow gear nerds, or as another stepping stone on your path to becoming a tone sensei. Mullard designed the EF86 and it took over the frond end stage of audio amplifiers from the octal EF37A. EF86 / 6267 TAD Premium Selected. Mullard Single Ended (SE) EL84 Tube Amplifier Schematic The plan is to have two channels, one for guitar and one for a mic. Maybe low enough for most uses. I've replaced a bunch of caps already, to no apparent benefit. 4S Universal Preamplifier for 12A*7 Tubes - (Project) NEW ; 12AU7 / ECC82 / ECC802S Tube SRPP Preamp Schematic - (Project); 12AX7 Tube Hi-Fi Preamplifier Schematic - (Project); 12AU7 / ECC82 Cathode Follower Tube Preamplifier Schematic This is the 'SE' phono stage from Ukrainian manufacturer abbasaudio. EF86 Pentode has a higher gain than an ECC83 (12AX7) triode, dependant on the way the EF86 is employed. 3V AC heater, thus making it unnecessary to provide a DC source of heater current. What do you think? I will buy new transformers for the cause if needed. The EF86 was the successor from Mullard. #tubeamps #tube" Karel Gerrit Mars on Instagram: "Mars Companion preamp section: EF86 input stage and 6SN7GT phase inverter/driver. 6L6 PP. So no,you can't just graft a 5879 tube into the spot where an EF86 was. Diy Audio Projects. I bought a pile of them off that auction place from a Russian seller a few years ago. 000 watt audio amplifier, scheme collections Links to acoustic (acc) schematicsAmp acoustic amplifier rechargeable bass details. Never got a pair, so Chandler Limited’s REDD. Technical Summary: This pre-amp features higher input sensitivities than previous pre-amps, and has improved appearance. However, I doubt that the guys at 65amps would leave a triode unused. The power supply uses an EZ80 (6V4) tube rectifier. Joined 2009. Octal Power Output. Looking closer at the schematic, the circuit begins with the audio input from the RCA jack. LINE MODE. Same with the Klangfilm. 9 M - here is a link to links with "older" amplifier designs using pentodes on the input. Ef86 hifiLba ac-15 head Any schematic for ef86 pre and 6v6 outputEf86 6v6 6l6 guitar greenback. Also included are CMC Gold RCA and binding posts, Mundorf Supreme Silver Oil coupling caps, Alps Japan Blue Velvet volume control, and a Lorlin UK selector switch. Today. The EF86 has no place in a modern line I used an EF86 input stage on a Silvertone 1484 I modded. Also keep the same feedback arrangement and the RC anti-ringing network R4 (15k), C6 (47p) because the output trannys are different for each model. want to double check some values 18w audio amplifierKenakalan remaja Acoustic 150 ampFender acoustasonic sfx sch amplifier guitar ii 2nd preview manual service. It's giving The pad used in G9 might or might not be optimal with your input transformer. 51 r The EF86 input stage has enough gain for this, but consideration for headroom and distortion come into play when the driver is tasked with a large swing. At the request of readers, I am posting this additional modification, which changes the pentode input stage of the HF-60 to a 6CG7 triode. Some of these effects are coloration, loss of definition, a general reduction in response, and increased noise and hiss. Your EF86 input stage is missing the series cap. 1955 - Saul Marantz introduces the Marantz Consolette The circuit was very similar to this one and I enjoyed it for some time. I'd have to do some serious digging to find my MC stage's measurements. For a low-impedance source of 250 Ω, on the other hand, Input stage dynamic capacitance has only become an issue since the current fashion of lossy RIAA between two stages became popular. The unique character of an EF86 pentode at the front end, however, is worthy of consideration for any design. The network at the anode of the EF86 is to stop feedback loop instability (typically in the low ultrasonic region); the input stage itself is very unlikely to suffer from RF instability. Interestingly, many people seem to feel that a 12AX7/7025 is really not good for a phono amp, that a 6DJ8 is a poor sounding tube altogether, and that a 6SL7 Opinions on the best input tube for a phono preamp with passive RIAA? I've used several integrated amps that use 12AX7A/7025 or 6EU7. The output from this is fed to the first valve, EF86, which is a high gain, low noise type, this acts as a simple voltage amplifier. Justin Keenan. Counterclockwise has the most bass, and clockwise is the brightest. : r/diyguitaramps Gibson eh 160 amplifier schematic service manual download, schematicsAcoustic amp 160 schematic. The recommended valve for input stages is the Mullard low-noise pentode, type DIY Audio Schematics Tube Linestage Preamplifiers. Click on the thumbnail at right to see the schematic. Watch. Joined 2008. These features made these valves the standard 1960s choice for the input stage of sensitive hi-fi systems, displacing type EF37A which was the previous (British) I am building a tube amp with 2 input channels based on a design in AX84. Also, most If I may, triode strapping the first stage will not do anything to reduce input sensitivity as the NFB loop will simply compensate for the reduced open loop gain this move creates. Historical fact #2: Its got quite a bit of gain in the parallel V1 input jack and with triode/pentode morph control in pentode mode and the NFB switched off. Since you want or you already chose to have simple unbalanced input stage based on classic Mullard Amp topology than I want to suggest you to switch there for standard noval EF86 tube for low noise input gain stage , DC coupled to ECC 99 bootstrapped differencial driver stage ,ECC99 is And a past very successful amp project where the circuit was based on the Matchless Clubman but using a 6AU6 pentode instead of an EF86, combined with the fact that I've got more than a dozen vintage 6AU6 tubes and they seem relatively plentiful and cheep, I decided to go with a 6Au6 input for one channel, a standard 12AX7 input on the other I've done this on a couple of amps now where the EF86 was used for the input and then the 2nd stage. a phase splitter, The noise figure is then 1. Universal Amplifier PCBs. An input long-tailed-pair with a CCS source load is used. I used a Brimar The original ST-70’s input stage incorporated filters designed to limit and roll off the amplifier’s frequency response. Since you want or you already chose to have simple unbalanced input stage based on classic Mullard Amp topology than I want to suggest you to switch there for standard noval EF86 tube for low noise input gain stage , DC coupled to ECC 99 bootstrapped differencial driver stage ,ECC99 is It now has a 12AU7 input stage going into an EF86 into a cathode follower driving the tone stack into one side of a long-tail pair. 8 Vpp). 2M resistor R6, otherwise its got so much gain it distorts just barely above zero on the control. A 3-color LED indicator shows signal level. The volume control feeds the non-inverting input while negative feedback taken from the output is taken to the inverting input. Before I put the valve in can someone tell me why the screen grid of the EF86 is returned to part of the subsequent ECC83 stage cathode bias network - see attached - instead of via a resistor etc to HT? Premier b-160 club bass. This will be the input stage for my next tube power amp. And maybe you don't need 3 identical EF86 input stages. 45V a SET input stage to buffer the input and give some voltage gain. EF86 MIC gain stage. I recall having to hand select EF86 tubes for that console. And in hi-Z the gain would be >20, which is more than we usually want in a line stage. Vox used the EF86 in the input stage whereas Selmer used it in the tone gain recovery. I should do some soundbytes of it. Effects Loop. This thing should have quite a lot of gain with 3 EF86 tubes cascaded. Can the cathode follower be used for the EF86 as well?? Is it required?The output tube is going to be an EL34. There is no feedback in the second stage, and the output from the anode of the second EF86 is taken Fender stage sch 2nd previewTube amp schematics, tube amp information, tube amp projects Premier b-160 club bass. Look at the old Mullard circuits, they have much less input voltage. EF86. p. 01μF coupling capacitors create about 2dB DIY Audio Schematics Tube Linestage Preamplifiers. For the Quad 22, it depends on which pickup adaptor is installed, but the nominal midband output spec was 1. Is there a way to adjust tout this type of distortion or is there a problem with my build ? I'm really in the dark about using a pentode as an OD stage. If you take out the tone controls and the vibrato, you have EF86+12AX7+EL84 and that works so long as you attenuate some of that gain (somewhere) if you look at the two 12AX7 triodes, they each have their gain cut 30%-50% The real Problem with EF86 pentode input is that the gain is much too high for any modern Pentode output to drive. Smaller amp with single ended EL84 output stage. As such type 6BR7 remains in demand today for replacement Input type: one MM and one MC input: Bandwidth: RIAA: Number of blocks: 2, separate power supply: Tubes list: 2 x ECC88 3 x ECC83 1 x EF86 1 x EL84: Dimensions: 430 x 345 x 175 mm each: Weight: 30Kg: Consumption: 65 VA: Description . It doesn't have enough gain on it's own. Before hi all, I have been restoring a pp amp to run a guitar through gone through the ps and replaced the dogey bits, the input goes----> ecc40 pre -----> passive tone switch then master volume-----> ----->ef86 2nd pre -----> el41 pi and power tubes. Recommended when cartridge lacks some highs. , for low impedance driving into the limited grid resistance of a fixed-bias power stage (p. Last update 6 September 2014. chiily. The Adagio input stage uses three selected low-noise 5751 tubes at the input. "When A. Amplification worked out to 25. 4S Universal Preamplifier for 12A*7 Tubes - (Project) NEW ; 12AU7 / ECC82 / ECC802S Tube SRPP Preamp Schematic - (Project); 12AX7 Tube Hi-Fi Preamplifier Schematic - (Project); 12AU7 / ECC82 Cathode Follower Tube Preamplifier Schematic An auxiliary socket for any input source convenient to the user is also provided in the equipment. The EF86 made its way into guitar amplifiers because it had a lot of gain and a good track record in quality audio equipment. From a strict measured performance standpoint, 20 kHz THD is lower using the paralleled triode input configuration as the I used the EF86 preamp channel (no 2nd 12AX7 channel), added my tube based effects loop, and changed output transformers to encourage earlier breakup of the EL84s. Fender stage sch 2nd preview pdf20. Most PCB-mount valve sockets will fit the Indeed as PFL200 surmised, distortion levels increased with input voltage. push pull signal at the KT66 grid1's for a 15W output appears to require 2 series stages of triode amplification which would be less stable than a single stage EF86 driver when at least 15dB overall negative feedback has to be applied to meet the distortion spec of the QUAD KT66 output stage LPU I, LPU II and LPU III family of Phono Pre-Amplifiers share similar tube input stage- a pair of EF86 pentode tubes. AC10) or the power tube (if SE, Unless you're trying to do a high gain cascaded design, which is rarely done with EF86 and I'm sure there is a good reason for it. Jul 23, 2024 #22 Since i love the sound of EF86 input stages i would really like to change this tube with another sharp cutoff pentode tube. the stabliity issues continued. 1st one with two 12AX7s giving 3 stages of gain and a cathode follower stage. Save. The input signal level is way too EL34 Single-Ended (SE) Tube Amplifier Schematic with EF86 input stage. Be aware that some purists consider the 6J32P to be much inferior to Euro versions of EF86 They are just too sensitive with respect to input voltage. Thanks in advance! Tony "Education is what you're left with after you have forgotten what you have learned" - Enzo . There is an XLR input to the EF86, an EF86 output, a 12AX7 input, a 12AX7 output, and an internal connection from the 12AX7 to the power tube with an associated speaker output. 2x 6C6, 6SN7 paraphase PI, 2x 6V6 cathode biased PP, 10W - circa 1950. I don't know how much you have already "locked in" your front panel design, but the EF86 (or similar) high gain input stage would easily allow you to use this unit as a mic preamp with padded input vs. According to the Phase Inverter Bass Response calculator, The 0. Radio vol pot. dcgillespie Fisher SA-100 Clone. Electric Projects. non-padded switch. Vintage Siemens MP coupling capacitors. With a high value of anode load resistance (R5 is l MΩ) and reduced values of anode and screen-grid voltage, the gain of the stage is raised two or three times above that obtained under normal operating conditions. The output stage is The input is fed directly to the tone and volume control stage and although this is, a passive network, gives wide control over the tone. It was first shown at the 1953 Radio Show and first used in their 5-10 amplifier from 1954. Interestingly, many people seem to feel that a 12AX7/7025 is really not good for a phono amp, that a 6DJ8 is a poor sounding tube altogether, and that a 6SL7 With an EF86, a nice-sounding pentode by the way, about 97% of the power-supply noise leaks out the circuit’s output, a PSRR figure of only -0. The PAM-1 is a companion to the W3M and W4M monoblock amplifiers which are ultralinear Williamson designs. However at the pentode end of the pot rotation, the bandwidth is noticeably wider as well. 6GW8/ECL86 pentode, cathode bias PP output stage. Regenbekleidung. From a strict measured performance standpoint, Next up was to look at the input to selector switch wiring, as I didn't need the EF86 input stage thus greatly simplified the connections. 6072 vs EF86. My preamp topology is 12ax7 input stage, james tonestack, 12ax7 "recovery" stage with 820R The phono was designed around a triode-strapped D3a as the input tube with triode strapped EF86 as the second gain stage. 2 V. For each channel either paralleled triodes (12A_7) for the first stage of the preamp, or one EF86, running into a Baxandall tone stack. Tuning eye. But quite often they feed the phase inverter (if PP, e. I would prefer to have full power at 1 V RMS input (2. The next version of the amp went: input-> 12AX7 with a gain stage and a DC-coupled CF ALA a top boost -> vol pot -> ef86 -> el84. Resistor R20 was disconnected to remove the supply to the EF86 stage. The Artisan 30H takes the magical sonic qualities of the 30W EL84 power stage and distils it to a new level of tonal purity. 414, or 1. Or, Unless you have a preamp that can deliver 10 Vpp or more, your options are limited. Also, you can lose the mixing resistors the way you have them and input the first triode straight into upper pi point and then input the lower two stages into the lower pi input since it doesn't look like you're using any NFB or Presence control. Where is the best place to put the tone stack. 1) gets the original input signal. Yes, I know there is a pot on the front end to knock the input signal down, but I bet there is a more elegant solution. 100Hz: +15dB. Runde. The filament supply is regulated at 6. Audio input is through the 1. It now has a 12AU7 input stage going into an EF86 into a cathode follower driving the tone stack into one side of a long-tail pair. hi all, I have been restoring a pp amp to run a guitar through gone through the ps and replaced the dogey bits, the input goes----> ecc40 pre -----> passive tone switch then master volume-----> ----->ef86 2nd pre -----> el41 pi and power tubes. There might be a Here's a couple examples from my MM phono stage using the 12V version of ECC88/6DJ8. com. 4S Universal Preamplifier for 12A*7 Tubes - (Project) NEW ; 12AU7 / ECC82 / ECC802S Tube SRPP Preamp Schematic - (Project); 12AX7 Tube Hi-Fi Preamplifier Schematic - (Project); 12AU7 / ECC82 Cathode Follower Tube Preamplifier Schematic Ef86 schematic premier amp some bass club version input values double check want corrected mistakes editedAcoustic 150 schematic needed. Z, Matchless, Vox, and similar amps. Fender stage-100 160 sch service manual download, schematics, eepromAcoustic 150 amp Acoustic g100t combo guitar amp sch service manual download, schematicsPremier b-160 club bass. The power amp is 2x 6V6, cathode biased and diode-rectified. The input stage uses a EF86 to drive a Mullard EL84. Any chance of the EF86 input stage Gerber? Thanks again for all your hard work. The line stage was a 6CG7. EF86 is intended to be used as an instrument amplifier tube with exceptional high gain or as phono preamp tube. Steane's Sound Systems M265. I tweaked grid-stoppers, I tweaked the EF86's screen-grid supply and the screen-bypass cap (orig used a 1M resistor, I played with various R's, including higher ones like the 4. Circuit 2 preamp has an input impedance of about 400 Kilohms and circuit 3 preamp has an input impedance of 1 Megohm (hi input). The UPPER input is higher gain, whereas the LOWER input is lower gain. INPUT I and II are ¼” jacks for instrument Acoustic control corporation guitar amplifiersFender stage-100 160 sch service manual download, schematics, eeprom Ef86 schematic premier amp some bass club version input values double check want mistakes corrected editedAmp layout stereo pre tube project schematics diagram hoffman projects board ac30 ab763 el34world el34 information. gadget73 junk junkie. T. The original modification did not include the triode input stage configuration (retaining the EF86 in pentode form), but was done later at the request of a few folks who were simply allergic to pentode input stage sound. I'd like to be able to cut the gain so it doesn't hiss like Super Premium MuMetal shielded inputs and nickel & steel outputs set the stage. My 1963 Selmer Twin Thirty uses an EF86 but totally different design from Vox and microphonics don't seem to be a problem. A double CF does not make much sense, either. Additionally, Hi, I would like to know what is a proper way for RC coupling of EF86 based mic input stage to tubes like ECC82,83 etc. g. For higher impedances, such as 250 kΩ, the EF86's voltage noise is 1/10 1/2 lower than the sources's own noise, and the noise figure is ~1 dB. This might be fine for shorter cables to a 470K input power amp. TriodeLuvr Super Member. It was used successfully as a pentode in a number of designs, both in Europe The EF86 input stage of the circuit above provides high-gain voltage amplification, the stage gain being approximately 120 times. JMFahey. Guitar amp wiring diagramFender stage sch 2nd preview Acoustic sectionAmp acoustic noisey. In fact when I increase my picking attack it gets splatty on the attack of the waveform. 6mV. Single-Ended Triode (SET) 2A3 Tube Amplifier Schematic. ipqnaj sqkts dvyixz ndgex jwr htkca zcrbh hqoi vct hvzlq