6l6 bias calculator amplifier. Members; iansmitchell.

6l6 bias calculator amplifier Tube Bias Calculator Let me do the math for you with this easy to use tube bias calculator. Optimize your amp's performance with our Tube Bias Calculator. Click any Calculate button to see the recommended tube bias currents in milliamps. That is for 6L6 tubes so I'm not sure what the 7868 bias at. Carefully remove the old, worn out tubes from the amplifier. Moderators: pompeiisneaks, Colossal. These power tubes will be operated far below their Here is a good read and explanation of how to measure and set bias in a Tube amp. The MAP-15 design thus offers an interesting feature: a The plate voltage for your amp is 375V based on the schematic, if you're doing cathode current biasing for a 6L6GC (specs at 30W dissipation) with 375V on the plates at 70% you're right at 56mA. Cathode bias amps must run HOT. In the case of a tube amp, bias is used to determine the ideal current flow in the tube when the amp is not in use. It looks like yours is a Fixed Bias amp so I would use 70% of max plate dissipation per tube. 7 very far off the -38 and I tried running same numbers for a EL34 and got 43. This will bias the 12AT7 even farther away from grid current, and into a more linear area of its operation. My understanding is, I replace the resistor on the HOW TO BIAS YOUR AMPLIFIER. True 5881 tube are about 23-24 watt max. com. The point made was to look at the operating conditions listed on the 7027 data sheet rather than those on the 6L6GC data sheet, because historically tube makers updated the maximum ratings for later 6L6 types but often carried over original 19w metal 6L6 operating Piggybacking is a good idea with an spst switch to switch back to 6v6 or a different sound. Rather than the suggested 70% of maximum plate dissipation, I was sitting at approximately 55%. Cathode bias amps are often favoured by guitarists because of their sustain and overdrive characteristics. The spreadsheet is set up to calculate bias for amps using class AB1 mode which is basically what most amp output stages use. This Proluxe amp kit was my first amp build. Since 2006 we have offered a single octal bias probe for use with a Multimeter. He measures the bias on the convenient pins on the printed circuit board. Some smaller amps with 6V6 power tubes Tube Bias Online Calculator. And know that even 6L6GC data sheets often reprinted conditions that were on the original 19w 6L6 data sheet. Accurately calculate bias voltage and current for power tubes. I'll take a look at the recommended readings, and thanks. The Peavey 5150 has no adjustment for bias. The individual self bias network method works real good for me. pdf), Text File (. The high-frequency alternating current used in tape recorders to lessen distortion is referred to as bias. Just my experience, and just my opinion. That should be the coldest EL34 bias, but it will still be hotter than 6L6/Bold/SS. Welcome To the Hoffman Amplifiers Forum December 23, 2024, 01:58:07 am: Welcome, Guest. 04 or 550 ohms, 2-3W. This is a negative voltage. 4. Enter Plate Current: DC Bias determines the ideal current flow through the tube in tube amplifiers that are not in use. The voltage divider bias method is a commonly used technique to Weber's bias calculator says my AB push and pull amp with 6L6's at a 395 volts on the plates, needs 51 mA to be at 70% dissipation. This website uses cookies to ensure that you get the best experience. If you set the bias to about 22V and 40ma, you will need a 22/. With the switch on the back of the amp in 6L6 mode I can only get these up to 29mA with the bias adjust maxed out. Now, leaving the bias set for el34s made my amp sound a lot better, more dynamic and punchy. It seemed like, as i recall whatever the numbers were for mA, I was say at 40mA well biased at about 70% (I'm making these numbers up to try and recall 'roughly' what I The measured plate voltage was 425VDC, and the measured plate current was 39mA. I assume this will be moved to the instrument amps section. This type of calculator is used to calculate the correct bias voltage for a BJT amplifier, which is an essential part of the design process. Plugging everything into Overview. 9 posts • Page Post by jimipage » Sat Nov 08, 2008 11:17 pm. 4 pF Cin: 10 pF Cout: 12 pF The final 6L6 amplifier runs straight through, not frequency doubling, on all bands. -User Name -Password. My question is- how In fixed biased amps 70% is usually considered the max bias at idle. 44 kB, 1224x1584 - viewed 169 times. In this thread Amp design suggestions Eli was suggesting a 6L6 AB2 design based on Mullard 5-20 topology with 12AT7 front end and ECC99 LTP and Mosfet source followers. Respecting the original thread, Eli asked to start this new one. From 360-400 to 480V, the load should be 1. com 35watt 5E3P Proluxe amplifier kit. g. 7 * 30/450) = 47mA. Use Hardly ever go wrong with 35-40 mA for 6l6's. Reactions: loudtubeamps and nonreverb. According to Weber's bias calculator, about 44. Requires separate digital volt-ohmmeter capable of is the power rating of the power tube, is the bias current, and is the plate voltage of the power tube. _____ Matt It's all about the The 6L6GC is a type of beam power tube employing a beam-confining electrode at cathode potential in place of an actual suppressor grid. What bias current do I want for my 6L6GC power tubes with the Twin Rever? The Weber bias calculator*, at 445 measured plate volts, suggested 47 mA but my amp wont let me go above 45 mA. Classic 50’s American Kits; Classic 60’s American Kits; Classic 60’s British Kits Bias Calculator. Maybe I should turn the bias adjust all the way down and flip the bias switch on the back of the amp to EL34 and see where the bias is? It is fixed bias but doesn't appear to have adjustable bias. Please login or So, tried the 6L6GB (19watt There are many web sites that explain setting bias. The schematic shows 6L6GC power tubes. txt) or view presentation slides online. I would never suggest running 6L6's at 600v and dont know many amps that require it. 9% on the 6L6GC tubes. Each tube in this comparison was installed in the same custom-built, fixed-bias single-ended The amp has the bias balance circuit in it. The 7868 is only rated at 19 watts. If I put in or out a 25/25 at a preamp tube, a huge difference is audible. 4 to 1. You may wish to have certain fixed bias amps (such as Mesa Boogie Using the "Tube Bias Calculator," the calculated bias voltage and resistor value required to achieve the desired bias voltage are 32. It was certainly running higher voltages than originally intended, maybe by 40-50V due to higher mains voltages, and The bias on the amplifier is set at the factory with whatever tubes are in it on the date it was born. There is a lot being left out here. AMPS. In my limited experience, with modern power tubes, I find a colder bias, depends on the amp but on my D clones around 60-65% seems to sound the best. . -User Name-Password Home; Help; Search; Login Try setting the bias with this -bias calculator, I like 60%, don't go more than 70% dissipation. This webpage offers two ways to calculate tube bias and plate dissipation. Jack Hoffman Amplifiers Tube Amp Forum, 6l6 bias pot value question. Welcome To the Hoffman Amplifiers Forum December 07, 2024, 05:29:27 pm: Welcome , Guest. Now I do have a vintage set of two RCA 6l6GC's that I ran in my D'lite and they also sounded better under 70%. When biasing to 70% or whatever percent you’re looking for you simply multiply the answer by that number divided by 100. You must enter Tube Type and Plate-to-Cathode Voltage above before calculating Tube Dissipation. This past summer I saw Transformers: Revenge of the Fallen and I was inspired to build an enclosure for a vacuum tube amplifier that incorporated the Decepticon logo. Posted Buy Nobsound Vacuum Tube Amp Amplifier Plate Bias Current Probe Tester 8 Pin Socket for EL34, KT88, 6L6, 6V6, 5881, 6550, KT66, KT100, KT120, 7027 (CT1-C, Cathode Current): Test Probes & Leads - Amazon. Requires separate digital volt-ohmmeter capable of reading current. I started with 670r & 750r, respectively. These probes are $25. A 51 tube database means you Photograph 1: DIY Single-Ended 6L6 / 5881 Tube Amp. The easiest way to make your Bass guitar amplifier work reliably and with long life . 6 thoughts on “ PP Fixed Bias circuit design and calculator ” Mark says: April 6, 2020 at 06:51. Plugging I can say that those bias numbers the tech gave you are way low for a single 6L6GC JJ tube. -User Name Robinette Calculator for 6L6GC. This is a Class A/B amp so we’re going to use the standard 70% (). 42mA), but do not 5E3P Proluxe Guitar Amp Build. 2 Impedance of an output transformer In 6L6 mode, the hottest bias is obtained by going with Bold/SS rectifier. backline There is a great YouTube video on how to bias Hot Rod style amps, by the guys at the "TubeDepot": "How To to calculate current, use ohms law. Home; Help 6L6GC: Ia = 55mA Rk = 380R EL34 / KT66: Ia = 72mA Rk = 360R KT88 (I couldn't find transfer characteristics anywhere): The desired sound of a Hi Fi Stereo amplifier is often very different than the desired sound of a guitar amplifier. 1 Fixed bias for vacuum tubes; 3. As long as you know (or can test) the plate voltage in your amp, and have a way to measure the idle current, you can determine where to bias it, using our calculator. TUBE BIAS CALCULATOR (for push pull class AB1/AB2) Tube Type: Plate Voltage: Power W: Plate Current mA +/-10%: Cathode Current mA For 8-pin power tubes such as 6L6, 5881, 6550, 6V6, EL34, etc. 2 Cathode bias or self-bias for vacuum tubes; 3. They really aren't 6V6's but more of some smaller 6L6 hybrid. Requires separate digital volt-ohmmeter capable of When biasing to 70% or whatever percent you’re looking for you simply multiply the answer by that number divided by 100. DISCLAIMER: LORD VALVE (W. A formula example is this: (0. Before I got it someone put new JJ output tubes in it and fender pre amp tubes. The Granger Amp bias probe measures in milliamps by insertion into the cathode This amp will handle all the higher dissipation members of the 6L6 family including the 6L6GC and the 5881. 8 times higher, 7K to 9K. The KT88 have 220k and 6L6' bias circuits I remember use about 100k. For use with octal tubes EL34, E34L, 6CA7, KT66, KT77, 6L6, 6V6, 5881, 6550, KT88, KT90. Bias is an alternating current of high frequency which is applied to the tape recorder to reduce distortion. These results indicate that the required resistor value to achieve the desired bias voltage is much higher than the typical range for 6V6 amplifiers. My recommended bias measurement method is the "Output Transformer Resistance Method. Very halpfull, thanks for your job. Or, as Chris suggested, you could choose a more linear driver tube. Bias Rite Instructions; Chassis Dimensions; Cabinet Dimensions; Cabinet Covering Swatches (Includes Handle Pics) 6L6GC – 30W. Tube values can vary greatly from one amp to the next. Members; iansmitchell. Tube Dissipation Using Cathode Resistor Voltage Drop. This amp uses the Fender 5E3 tweed Deluxe preamp and the Fender 5E5-A Pro power amp to create a very powerful but still tweedy amp. General discussion area for tube amps. (link removed) Jul 22, 2014 #19 ; B. never use the absolute max of a tube as a bias ceiling - that is the point to where the tube will become From mid 80’s I went back to tube amplifiers and tried to build a 30W 6L6 push-pull mono block pair with 6SN7 drive tube. Customer ” Joe” puts his four brand new matched Tung Sol 6L6GC-STR into his amp and he checks the bias on each of the valves. It can be built for CW as well as AM operation. Bias voltage is like a control valve that regulates the current through the power tubes. Our bias probe measures true bias current. Use this tool at your own Risk. I am interested in progressing with this design, looking for any assistance 😉 Cheers, Hoffman Amplifiers Tube Amp Forum, How Low Can I Go? (cathode bias resistor) Welcome To the Hoffman Amplifiers Forum I'm tuning a SE amp that has a switch to select a cathode bias resistor for a 6V6 and a 6L6. The best way is to observe the live current. Bias refers to the high-frequency alternating current applied to a tape Amps without adjustable bias include Mesa-Boogie amps, some Peavey amps, and even some Fender amps (early versions of the Hot Rod Deluxe/Deville and Blues Deluxe/Deville, for example). Bias determines the ideal current flow through the tube in tube amplifiers that are not in use. Some like to use 60% thinking it may extend the tube life. I wouldn't use that chart at all. www. I only had a 50mF 100V cap (guess a 25mf is used mostly). Also, the idea that it's OK for bias to change No-calculation examples: A higher voltage (450v) deep class AB amp might use a 4k primary (possibly smaller), while a lower voltage (350v) hotter class AB amp might use a 6. The resistor in there now 15. The schematic shows a voltage of -48 at the junction of the two 270K resistors. You can: choose among most common power vacuum tubes (I am slowly adding more), set the operation modality, among Hoffman Amplifiers Tube Amp Forum, Bias Resistor Calculation. If I take (switch in my case ) out the one at the power tubes, I can not hear any 6L6 fixed bias/PT question. I have an older Hot Rod Deville 410 I bought used with Sovtek 6L6’s in it. 1 Output stage, or power stage. 6. The beefiest PT I have at this time is a Hammond The Tube Bias Plate Dissipation Calculator calculates the amount of power that is dissipated as heat in the plate (anode) of a vacuum tube. Cathode biased amps run at max signal at idle, so with cathode biased amps usually 90% is acceptable for real class A, and 80% to 85% for class AB1. Start to bias 6l6 tubes, or any other types, by plugging in the bias probes and the new power tubes. The bias range for the Hot Rod Deville can go between 70mV-80mV. Kits. 1. Grid input load of next stage neglectable. a standard 6L6 is 25W max, 22W for calculations, 18-20W to be more realistic with tube quality and tube life. I have balanced the two 6L6GC tubes using the bias resistor that was in the amp. is to purchase a very well matched Quad of 6L6 tubes (6L6GC is best for long life if the amplifier is driven hard into overload clipping). Try using individual self bias circuits, separate the cathodes, and use two 680 Ohms and 100uF self bias networks, one for each cathode. Welcome To the Hoffman Amplifiers Forum December 20, 2024, 10:11:57 pm: Welcome, Guest. I also have a Carvin Belair, 4x El84 amp, also sounds a little bit colder. 5W plate dissipation or 51. 1 mA per tube for 70% dissipation. Plate Voltage: Hot (70%) Avg (60%) Cool (50%) 300V: 70mA: 60mA: 50mA: 325V: 65mA: 55mA: 46mA Search titles only By: Search Advanced search 2A3, 300B, EL34, KT77, KT66, 6L6GC, 7591S, and 6BX7. 1 Single Ended vacuum tube amplifier; 4. This is why fixed bias amplifiers - which don't experience the bias change relative to output level - can generally be set to idle at lower current, which promotes longer tube life. If Vp is increased, Ip must DEcrease so the tubes don't melt. For amps with cathode bias resistors you can simply measure their voltage drop and use the Tube Dissipation Using Cathode Resistor Voltage Drop calculator. This bias calculator makes it possible to determine the current by giving information about the Use this calculator to determine the bias current for an amplifier’s power tubes. The only way to adjust bias is to modify the bias supply. Given below is the tube amp bias calculator to find the bias in ampere or milliampere (mA or A). In many tube amps, the bias on the power tubes is adjustable. Another question- If there is no substantial current flowing in the bias circuit, how do different value bias feed resistors affect the bias on the output tubes? For example, 220k vs 100k on the same tubes in question. My bias probe is a Weber BiasRite (now discontinued) and it will show plate voltage and current draw with the flip of a switch. Enter the plate voltage and type of power tubes to get the bias current at various levels of plate dissipation. If you want to run a little hotter bias, try running EL34 mode with Spongy/Tube Rectifier. Schematic in Post # 1 has both output tubes cathodes connected together, and they are connected to a single common self bias resistor & bypass cap. Global Moderator; > what to bias the 6L6's at "Bias" includes plate voltage. 85 percent but you will wear out the tubes quicker! 12 watts divided by This calculator allows you to compute and tune loadline and operating point of tube amplifiers’ power stages. . Biasing Tube Amplifier Calculator; Biasing a Tube Amplifier; Build Guide - 2 Tube Regenerative Radio; Build Guides for Pedals; Step 6: Slowly turn the bias pot towards hot until you get a reading of about 35mA (ideal bias point for 6L6GC). You would need to input your power tube’s details and the voltage you got earlier. 8mA at 100% PD - do not exceed this for safety reasons. 6 Biasing techniques. Plus modern Fender 6L6 amps tend to specify an idle cathode current of 30mA. With that, and the info from the tube type, a tech can do the math and figure out the appropriate bias range. By visiting the Weber Bias Calculator, and the Tube Amp Bias Calculator, it was advised to set my bias to yield 49. To find the ideal plate current for a bias I ended up going to Webers bias calculator and plugging in my numbers class AB 6L6GC 406 volts plate voltage (pin 3 and 8 ), It comes up with 51. com FREE DELIVERY possible on eligible purchases allowing for quick and efficient testing without the need for conversions or calculations Back in 1946 when the amp was produced, however, no more than about 20 watts was considered the maximum plate dissipation for a 6L6, not the 30 watts for a modern 6L6GC. NEW Matt presents bias and operation data for the 6V6 tube in SE operation - 6V6 Single-Ended (SE) set the dissipation wanted at the B+ and load and calculate a current to get it by the bias. In these calculations, 5% of the cathode current is assumed to be screen current Hoffman Amplifiers Tube Amp Forum, How to Bias a Fender Concert amp. Recently I had a 1960's 2x 6L6 cathode biased amp in for some work. I've seen these listed as 30 watt tubes by thetubestore. A voltage divider bias BJT amplifier calculator is a tool that helps you design and optimize bipolar junction transistor (BJT) amplifiers. (Title Changed) Welcome To the Hoffman Amplifiers Forum December 22, 2024, 04:38:28 am: Welcome, Guest. 10V and 754. Here is s video to simplify the process. tedweber. For me when biasing amps every amp I have ever used gets to a point where it starts to thicken up sound wise, I almost with out fail like the amp set This is an online calculator designed to determine the bias of a tube amp in amperes or milliamperes (mA or A). More Information I agree. Tube Type and Plate-to-Cathode Voltagemust be entered for all calculations on Bias is high frequency alternating current applied to minimize distortion in a magnetic tape recorder. 5 Amplifier classes; 3. Didn't get high enough plate dissipation, so I went to 400r and 225r but it's still a I made my amp project switchable between cathode bias and fixed bias. It uses a 6AG7 oscillator (can be modified for VFO) and parallel 6L6s running 75 watts input on 80, 40, 20, and 15 meters. 7 will just get you out of crossover distortion and you can go as high as . The tube amplifier replaces a solid-state amplifier which was driven by a tube preamplifier. 4mA of idle plate current. Each tube sample was installed in the same custom built, fixed bias single-ended guitar amplifier (see schematic) with a Fender black face style preamp circuit. 44Ω, respectively. Plate is 483/480 GR. Bias refers to the high-frequency alternating current applied to a tape recorder to minimize distortion. 1 which is about where it was set when I measured it at the bias point at R21 when I started this biasing quest. Biasing Tube Amplifier Calculator | Amplified Parts . ) Logged Willabe. 500ohm-550 would work and be pretty optimal. For the tube amplifier circuit I FINAL AMP KIT SALE Take 10 off Amp Kits till Monday 12/23 with coupon code FINAL. Next you will need to put in the two 6L6 bias resistor in place of the 10 ohms R9 and R23. In a tube amplifier, bias is used to determine the ideal current flow in the tube when Use this calculator when you measure the actual plate current. Wait for it to calculate your bias point The increase in bias voltage pushes the tube toward class B operation where no current flows at the zero-reference line of the signal. I have a customer who wants an amp with an output along the lines of a Bassman/Super -- basically a pair of fixed bias 6L6's. Get started today! This is an online calculator designed to determine the bias of a tube amp in amperes or milliamperes (mA or A). WHITTAKER DBA NBS ELECTRONICS) WILL TAKE NO RESPONSIBILITY FOR ANY INJURIES OR DAMAGE SUFFERED BY ANYONE AS A RESULT OF THE MISINTERPRETATION OR MISAPPLICATION OF THE INFORMATION CONTAINED IN The cheapest solution. , Bias voltage is On the bias calculator I should have these at 38mA for a cool 50%. True pentodes like the EL34 may be different though. 00 and available in our online store and can be used with 6V6 - EL34 - 425V B+ 6L6GC 4k center tapped ot Push pull class A Fixed bias TDSL says this for cathode bias: B+ 360 Vg2 270 Ia 50 Ig2 9. jpg (429. Tube Bias Calculator II *Merlin Blencowe believes up to 85% is OK for Class AB Fixed Bias Amps. But why 10 Ohm resistor on 0,24V is as big as 1W power? Cool – glad it helped you. He sets the I believe the only reason manufacturers ever used cathode bias in AB1 amplifiers was the cost savings. 3. Stage 2 phase spliter calculation, plate and cathode output. For 6L6 valves then yes you would be around the 70mV range. With those operating conditions it would also be able to swing more volts into the 6L6 grid. You will need this number to calculate total dissipation. It requires running the output tubes much harder at idle than if they were fixed biased. And really, the 1 ohm method works for both fixed bias and cathode bias circuits. For doing bias calculations with JJ 6L6GC tubes, I've always used 30 for the dissipation watts, but I've also seen/heard people use 25w. Measure the new individual bias voltages. Many run in the 460-480 range. Save Share Reply Quote Like. To calculate the ideal bias range for any amplifier a tech will first measure the amp’s plate voltage. 0 Reply. The amp as designed gets its tone from the preamp, the power amp is loud and strong, but the tubes run very cool. You must re-calculate after changing values by clicking any Calculate button. TUBE BIAS CALCULATOR (for push pull class AB1/AB2) For 8-pin power tubes such as 6L6, 6V6, 5881, 6550, EL34, KT88, KT66, KT100, etc. Step one is to calculate the output 6L6GC bias point Cookies & Privacy. 6l6gc's are 30 watts max plate dissipation per tube. Select your Plate is pin 3 and Cathode is pin 8. I suggest that in the typical fixed bias AB1 guitar If you are converting a fixed-bias amp, you need to look at the plate voltages and do some calculations to figure out if you are overtaxing the 6L6s. It will also handle the KT88 and 6550 tubes without modification. Please login or register. The resulting Proluxe is a classic all tube (including tube I plug these numbers into Weber's bias calculator (the voltage/resistor calculator method) and I get 10 watts per tube and 26ma plate current per tube . After having built EL84 amps using both Fixed and Cathode bias, I’m convinced that fixed bias is the way to get the I'm working on A Fender DeVille 60 Watt amp with two 12's Eminence speakers. Skip to content. and it wasn't very low below the 70% I bias at, but I didn't calculate the % diss at that point. Any work inside a tube amp is not "safe," so exercising due caution, this method would not be a threat to you. I took the plunge a few years ago and ordered a BootHillAmps. The Measured Voltage Gain Test Setup. There's certainly parts of the chart that don't apply, and out of whack. Hoffman Amplifiers Tube Amp Forum, Rob Robinette's bias calculator . Bias Settings For Safe Plate Dissipation Class AB: 70% CALCULATE PLATE DISSIPATION Based on Plate Voltage and Cathode Current Readings. Then by R=V/I, the Load Impedance must increase to properly absorb the power. Step 7: Use your ears to determine the best sounding bias point for the EL34s (e. That bias pot basically sets the biasing of both the 6L6 power valves in your amp, so you only really need to set it for one valve because if your amp is using a set of two matched 6L6 valves, the second valve should bias up close to the other, ideally when biasing the power valves in an amp, you need three pieces of test equipment, a Sine/Squarewave Signal I intend to use traditional fixed bias in order to maximize my plate and screen voltages (and, really, because it's the right thing to do ), but this means pretty low value grid circuit resistors (100K is the max for fixed bias according to the 6L6GC data sheet, although it seems I regularly see this exceeded -- 220K, especially in guitar amps I was trying my amp out with EL34's the other day, so I had the amps bias switch set over to "el-34," and of course when I put my 6L6's back in I forgot to change the bias back to 6L6. So I wanted to hear some feedback. Grid bias calculator mU factor (approx): 8 Cgp: 0. They tend to vary a lot on the Devilles that is on one amplifier I have gone around the 70mV mark, on others I have gone a lot closer to 78mV or so. "You measure the SLO-Nakid 6L6 SLO-100 2x6L6 40 Watt Overdrive Channel only with FX Loop and Switching deleted and laid out for a blackface 2x6L6 chassis such as the Bandmaster How to Bias a Tube Amp Measure and adjust plate dissipation. Sounded a little bit flat to me so I decided to leave the pre amp tubes alone for now and change the output tubes to better ones and see what happens. As above you have to know the plate voltage to calculate the tube bias and plate dissipation at idle. If you have for example a 250 ohm cathode resistor for cathode bias, adding a 1 ohm resistor in series with that won;t change the bias to the tube In many tube amps, the bias on the power tubes is adjustable. And . Let’s say we found it measured 420VDC (). Cathode biasing is usually done closer to class A than fixed for several reasons, the upshot of which is that the output tubes will idle at higher current levels. Just remember the plate load impedance of a 6L6 is lower than that of a 6V6 so you'll be pushing the 6L6 a bit, and the heater currents on a 6L6 are This has left me with 3 sets of 95-100 percent 6L6 power tubes that are quietly sitting in a box. just read the voltage across the self bias resistors, and see how well they match, when the tube is new, and when they have been operated for years. and they can take a beating. 6k primary. Search for a biasing tube amplifier calculator online. P=IV, I= P/V 22Watts/417VDC = 52. 6L6: 400: 60-80: KT88: 500: 80-100: Example of Tube Bias Plate Dissipation Calculator. For wattage you'll measure the AC voltage at the speaker on the amp - make sure the speaker or a dummy load is connected, and typically you'll run a sine wave into the amp. 5 250ohm shared impedance: 9,000 output power: 24w 3. We will continue to offer these because in conjunction with a Multimeter this is the most cost effective tool for measuring true plate current allowing you to accurately bias your amp. To try out different bypass caps I installed a switch. Solving for we get. The 6CG7 (same as 6FQ7) would be a very good choice. It depends on your own amplifier and I would suggest you trust your ears. This bias calculator makes it 6L6GC Comparison of Current Made Tubes _ Amplified Parts - Free download as PDF File (. 49k According to several bias calculators on the internet I am currently seeing 15. When Biasing the amp the wheel is maxed The formula for biasing is the plate dissipation of the tube (12 watts for standard EL84’s or 9 watts for the JJ EL844’s) divided by the plate voltage (let’s use 350 for this example) times . The original question was optimum OT primary impedance under specific conditions. I will be using it in my up coming 6L6 SE-UL amplifier design. Usually in the pass I was told, forgetting plate voltage for a monument, that 6L6's should be biased around 30 to 35 mA for about 70% dissipation (estimate). Arrow points to the insertion index notch. I selected a popular circuit diagram see picture: Stage 1 voltage amplifier calculation, plate output. 3 Gain of the voltage amplifier with self-bias; Chapter 4: Integrated push-pull amplifier. How to Measure Bias. More Information. Consider an amplifier using an EL34 tube with a plate voltage of 450V. This digital instrument is designed to calculate a tube amplifier’s bias in milliamperes (mA) or amperes (A). misobwno abn ccv lro vnv dlbmpm ilr cpkxci aaz zaiu