I'll build an autotransformer and play it safe. When saturated the harmonics are rich and dynamic. El84 Max screen grid dissipation by Gaz Wed Apr 13, 2011 1:29 am Been losing sleep over screen R values in an AC30 type build. This calculator allows you to compute and tune loadline and operating point of tube amplifiers' power stages. The Gold Lion's just sound great at any volume level. I'm measuring plate voltage on a PP amp with EL84, and when turning on Vak jumps up to 380V before falling and hovering around 300V. I think I have a quad or so of those Rooskies 360v on the plates, 338v on the screens, fixed bias at about 62%. It's got relatively low plate and screen voltages at about 310 and 304 with respect the cathode at about 10.5 volts. It may not display this or other websites correctly. by Gaz Thu Apr 14, 2011 9:51 pm, Post Are you subtracting the cathode voltage from the plate voltage to get the 340V calculation? p.p.s. Regarding screen grid resistor size, from 470R to 1K there is some local negative feedback happening with EL84 IME. You see 380 volts when the valves are not drawing current at first switch on. With the amp fully warmed up, can you see any hints of red color anywhere on the plates? $50.00 Details Add to cart Yes, unfortunately I've seen them glow too many times. Enter maximum price Shipping Free shipping. By Rob Robinette The other issue is the voltage. Maybe that's pushing it a bit (+13%). Thank you for your feedback. It may not display this or other websites correctly. Plate Dissipation (max) 25. It's the average of all of these points that determines the total dissipation. My amp tech states that Peavey's Classic 50 actually does an honest 50 watts. It has a very smooth sweet breakup just like the JJ EL84 and it will breakup a couple decibels earlier. EL84 Page 1 of 8 Telephone: +381 18 550 741 EL84 is A.F. The B+ is actually (301 - 12) = 289, so the power is 289 * 0.047 = 13.6W per tube (measured at the cathode). I think it's happy now. It is a Many amp designers run these tubes at 400V to 430V on the plate. But when you get above a certain voltage, pushing the current in an el84 can get dangerous. The Russian 7189 tubes have been fine in it since then but not before we destroyed some other tubes in the learning process. So now I'm at 9.8 watts per tube of actual "plate" dissapation, or 81% dissapation. The EL84 is a vacuum tube of the power pentode type. by Ian444 Thu Apr 14, 2011 10:41 am, Post Where did you get it? screen grid resistors set the difference between the plate voltage and screen voltage. Another volt is lost across each tube's separate current sense resistor (2 Ohms) and trimpot (10 Ohms). 1 voltage Vg1-100 (V) Cathode current Ik 65 (mA . Multiply the plate-to-cathode voltage by the plate current to get the plate dissipation. I was under the impression that JJ EL84 can easily survive 340V B+ and 340V on the screens up to max power without glow, but have not tried it myself. For cathode bias, you can run the plate dissipation anywhere between as high as 90-100%, or as low as say 60% - but the higher you run it, the better it will sound. the choke i'm using already has a 750R DC resistance, which I thought would be enough. I have the impression that EL84s fall more strongly than most into the "they dont make em like they used to" category. This tube has solid lows with warm bright mids and shimmery highs. Gaz, I believe you know what you are talking about when you see screens glowing. I just finished an EL84 push-pull amplifier using Electro-Harmonix (EL84EH) tubes. Turn off all the lights in the room, and allow your eyes to adapt to the dark. ?--- and the guaranteed lifetime in hours ? EL34 triode mode connection. You want to make sure that idle dissipation is not more than 50-75% of the rated plate wattage. Thats what I would be afraid of - the IQ being in dissipation spec initially and going red plate after several hours (when youre not looking, of course). WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES. Tube specs say max voltage is 300. Carvin runs their EL84 amps at right around 400 volts in fixed bias, with no apparant reliability problems at all. It's also common for cathode biased EL84 amps to run at 100% plate dissipation.Dr Z amps idle happily at 14 watts. @ 1 Volt peak input signal, with 16dB global negative feedback. Matched versions of this tube use Apex Matching Choose burned-in tubes for maximum stability and performance. I get about 12.5V on the cathode. amplifier. I"ve seen them with years of service on the original tubes. Amps with the cathode resistor you mentioned are cathode biased and generally run at a higher idle dissipation. Max Output Power 2x ~12W. My Mesa Express 5:25 is at 360V plate & 300V screen in fixed bias mode. EL84 - max. by Gaz Wed Apr 13, 2011 1:29 am, Post I think you may be unpleasantly surprised by the results wth only a 560R shared resistor at those voltages. Posted by garymuffley (D) on August 23, 2013 at 08:40:13 . V: Screen Current (max) 50. mA: Screen Dissipation (max) 8. by Alexo Wed Apr 13, 2011 2:27 pm, Post 300V is not so bad. by Gaz Wed Apr 13, 2011 6:06 pm, Post I'll see where it goes overall for wattage. You are using an out of date browser. RE: max plate voltage el84. I'm running 300V B+ and a shared bypassed 110 Ohms cathode resistor. OK. So at 350 to 400V on the plate, what kind of plate dissipation (at idle) is common or to be expected? I'm getting about 340V on a Spitfire clone I have. Life is a tale told by an idiot -- full of sound and fury, signifying nothing. I have a few 5 watters kicking around. If the plate voltage is too high, it will be hard to impossible to cathode bias. by pdf64 Thu Apr 21, 2011 8:38 pm, Post Better to be aware of the dissipation each EL84 has. Hi guys, These questions relates to EL84/6bq5 pentode vacuum tubes. Tube Max Design Dissipation = Watts 100% Pa: Class A Fixed Bias: 70% Cool = mA . Vox AC30's are up at 350v on the plates.It's common for guitar amps to go beyond design centers. I just did a traynor that had only one common resistor for the screens . Hey, this company claims to be running 6BQ5's at 700 volts for 35 watts per channel, although I can't find any info mentioning that number today. Oh nice! It's the average of all of these points that determines the total dissipation. Gold Lion EL84 - All tubes in the EL84 family are tested in a cathode biased amp where they are really pushed and their harmonic content blooms. Matched versions of this tube use Apex Matching Choose burned-in tubes for maximum stability and performance. Marshall did something like this on the early amps. The JJ Electronic EL84 is a solidly built EL84 / 6BQ5 with excellent tonal qualities. Dissipation was at about 95% for both plate voltages. I'm curious to see what you come up with, as I've never seen blue screens myself. If you can measure the plate voltage and plate current, then you can calculate the plate dissipation. The plates look to have a different coating than anything else coming out of new sensor in EL84's and this, combined with a heavy gage crimped plate seems to really keep the noise down. W (*) These specifications are provided 'as-is', with no warranty of any kind. The PT is nominally 275-0-275, although I was measuring 308-0-308. Use of these parameters shall be entirely at the user's own risk. I'm still left wondering why the "stock" values from the schematic weren't giving me something closer to the voltages on the schematic. Product Data Part Numbers Think'n this could be my new "Forever" Tele -An Am Pro II. JavaScript is disabled. It may not display this or other websites correctly. Ready to ship in 1-3 business days. Fixed bias. I really would prefer to pop in a couple of power resistors for the filament and then just connect it to my 247v mains. I would turn it down a little. You do not have the required permissions to view the files attached to this post. Product Data Part Numbers The EL84M will run at up to 500 volts HT and also it is designed to withstand the vibrations that are experienced in military systems. I don't think they meant the peak of a waveform as we typically see "peak" used. 1 el84 power pentode p e n t a l a b o r a t o r i e s 9740 cozycroft avenue * chatsworth * california 91311 (800) 421-4219 * (818) 882-3872 * fax: (818) 882-3968 But typical SE operation is 250V. JavaScript is disabled. At idle, None of the aforementioned values dissipated over the 2W watt max. by Philoffline Thu Apr 14, 2011 8:57 pm, Post { P = E x I } From this batch, tested at 400 volts, a tube with 18 ma idle current would be dissipating 7.2 watts {400 x .018 = 7.2}. Guitar amps routinly run EL84s up near 350V. That put me at about 388Vdc plate, about 33ma per EL84 (at the cathode) and a little over 12W dissipation at the plate. For cathode biased amps, 300v is about the norm, +/- 10 percent. Sovtek EL84M lifetime is estimated to be 5000 hours versus 3000 hours for a standard Sovtek EL84. Another way to tell before your eyes can is to use a digital camera - their CCD's are quite sensitive to shortwave infrared. According to the datasheet, 300V is the maximum value. Any chance you could post a pic of the glowing screens in question? I have it on my bench and never considered the screens which are fed by a shared 560ohm resistor off the B+1. The EL84 is designed for a max plate dissipation of 12 Watts, referring to old tube data books. Each EL84 also has it's own 2 Ohm (unbypassed) cathode resistor to measure bias current, and I'm using a 10 Ohm potentiometer to adjust the bias balance between the two tubes. please help me. I looked at some original manufacturers EL84 data sheets, and some modern EL84 data sheets. *When the heater and positive voltages are obtained from a storage battery by means of vibrator, the max. What do you mean by "bypassing to ground?". between the plate and screen that you can measure. The PT looked close. Unlike 6v6 tubes, where you have JJ's and some others that exceeded the vintage robustness specifications, el84 is seemed to be a tube that suffers from modern production standards being less robust than the vintage tubes that survived in amps that sometimes abused the hell out of them. Thanks DT7. All the data sheets for EL84 tubes give a max plate voltage of 300V and a plate dissipation of 12 watts. You must log in or register to reply here. When saturated the harmonics are rich and dynamic. You must enter Tube Type and Plate-to-Cathode Voltage above before calculating Tube Dissipation. Everything would be so much easier. Amps with a single EL84 output tube are probably class A and will run normally at around 100% max. Don't forget the fact that your 47 mA. I'll try another resistor. plate dissipation: 12W, anode voltage: 300V, screen voltage: 300V As you can see from the data, only the EL83 has different power and anode voltage ratings, which backs up my hunch that the EL83 is not quite the same in character when compared to the 6P15P and SV83. It may not display this or other websites correctly. The first dings in a new nitro guitar are painful, Tinnitus is ruining my life. JavaScript is disabled. Infrared basics for digital photographers, http://s69.photobucket.com/albums/i43/Ty_Bower/Tubes/P1070379.jpg, http://s69.photobucket.com/albums/i43/Ty_Bower/Tubes/P1070380.jpg. I'll give it a try to see if the plate is glowing. Just like when factoring plate dissipation in a push-pull amp, it's okay to cross the line because it's only for a small portion of one half of the signal. Thanks DT7. I measured 10.4 Volts across the shared 110 Ohm cathode resistor, which is 47mA per tube. Lots of builders run them in the mid 300's. Psychonoodler once pointed out the the real criteria is is plate dissipation = 12W. The 70% figure refers to fixed bias amps. Enter Plate Current: DC milliamps Plate Dissipation = watts = Plate Voltage * Plate Current. I just put a pair in an el84 driven train wreckinspired build and they sound spectacular. Sorry if I was unclear in my post, but those measurements were taken with max signal, not at idle. They don't last as long, sure, but they generally give a few thousand hours all the same. So, dont worry too much about the plate dissipation. On the Spitfire clone I have, a 120ohm cathode resistor yields plate voltage to about 365V using a GZ34 rectifier (JJ). Re: El84 Max screen grid dissipation. This tube can replace any EL84 or 6BQ5 tube. Post . For example, 25 ma at 360 volts is 9 watts, about the maximum for the EL84 whose maximum plate dissipation is 12 watts. When saturated the harmonics are rich and dynamic. IME, however, doesn't mean the tube's gonna fail imminently, as long there are sizable screen R's and dissipation isn't through the roof. You have not told us which amplifier it is. Going through the calculation I get about 17W @ about 48ma at the plate, which seems high to me. https://www.bvwtm.org.uk/articles/Valves and Valve Testing.pdf, Music Reference RM-10 Vacuum Tube Amplifer, SYclotron Audio | The Red Light District, p4. JJ's rugged construction of this tube offers high reliability without any compromise to the sound. Subtract the cathode voltage from the plate voltage, to get the plate-to-cathode voltage. Plate Dissipation % = % = Plate Dissipation / Tube Maximum Rated Dissipation. Cabinet Plate with Lily of the Valley Flowers and Violets, Royal Munich, Bavaria, Vintage Plate, 9.75 Inches If it glows, it should do so when more signal is applied, usually past clipping. You must log in or register to reply here. Bear in mind that amp has a cooling fan in it !! Grid No. The voltage rating of electrolytic capacitors that are employed for B+ filtering, has nothing to do with the life of an output tube. Vox worked that way for over 40 years yet. tubes receive a lot of vibration fro the speakers and being lunges from gig to gig in the back of a van. My Peavey amp's schematic shows a plate supply of 332V. It's got relatively low plate and screen voltages at about 310 and 304 with respect the cathode at about 10.5 volts. mbratch Member Messages 2,379 Feb 8, 2010 #7 TopBooster said: And sanded it down and refinished it! It makes soundwise most probably a great difference if you run them at 140 % or at 70 % (like many amp gurus recommend). FWIW, I serviced an EL84 amp that was running them at 400 and many tubes weren't up to the task. The JJ EL84 nails the classic sound of this tube. Turn off all the lights in the room, and allow your eyes to adapt to the dark. But do amp manufacturers generally run them higher than 300V? Some of the add-ons on this site are powered by, Amps/Cabs Tech Corner: Amplifier, Cab & Speakers. Sodo we know who were the ones that Dumble refused to build amp for ? As they heat up and draw current then that pulls your HT (B+) down to 300 volts. The grid voltage was -45.1V DC (yes, a negative voltage). It is used in the power-output-stages of audio-amplifiers, most commonly now in guitar amplifiers, but originally in radios.The EL84 is smaller and more sensitive than the octal 6V6 that was widely used around the world until the 1960s. Post If you are getting higher current draws with a guitar than with a signal generator, that just suggests that you need to increase the output of your signal gen. a little to match the guitar level. "Note that what most manufacturers pass off as "true Class A" or "pure Class A . If I were you I'd check the dissipation at max signal by checking the voltage across the resistor, divide by the resistance as usual, and multiply that times the voltage from cathode to screen with at max signal (not idle signal). The new JJ EL844 is an entirely new tube that dissipates 9 watts and is a drop in replacement for EL84's in most all amps. by Andy Le Blanc Sat Apr 23, 2011 11:58 am, Post Output Pentode . Alexo, you're totally right about the output level of my scope! An interchangeable North American type is the 6BQ5 (the RETMA tube designation name for the EL84). It sometimes takes a few minutes for them to get warmed up (see: stressed out.). The words Fender, Telecaster, Stratocaster and the associated headstock designs are registered trademarks of the Fender Musical Instruments Corporation. This tube has solid lows with warm bright mids and shimmery highs. So, keep safely under that. TDPRI, short for Telecaster Discussion Page Reissue, is the leading online community and marketplace for Telecaster guitars. I'll try another resistor. Power Stage: 2x 2 EL84 power vacuum tubes in Push-Pull Ultra-Linear configurat I have a few 5 watters kicking around. I have completed the build, double checked the connections and the amp works. Total, each EL84 has 117 Ohms cathode resistance. The Gear Page is the leading online community and marketplace for guitars, amps, pedals, effects and associated gear. ! Most amps for which the 100% dissapation rule has been used are running around 300 to 330VP and 300V on the screens. Total, each EL84 has 117 Ohms cathode resistance. The Manual rates the EL84 at 300V MAX. Larger tubes such as 6550 and KT88 are happy with 30 ma. 2 dissipation Wg2p 4 (W) Grid No. With the amp fully warmed up, can you see any hints of red color anywhere on the plates? Both amps are SS rectified, have two 12ax7s and 2 EL84s, and an 8 ohm 12" speaker. Ready to ship in 1 business day. by Ian444 Fri Apr 15, 2011 9:28 am, Post Great idea on the digital camera. Unlike 6v6 tubes, where you have JJ's and some others that exceeded the vintage robustness specifications, el84 is seemed to be a tube that suffers from modern production standards. That is 25% higher than the stated max values. You must log in or register to reply here. It's a 1967 Harmony H415. I have a Seymour Duncan 84-40 amp that runs the plates at 550 v, however the screens are half that at 275 v. Well, I tried a 250ohm cathode resistor. The power P, is equal to the voltage E multiplied by the current I. Screen current is small and ignored for the purpose of the above calculation. Max rating on the EL84 is 12 watts, but I suspect these amps must be measuring higher than that (?). I've seen some varieties begin to shown signs of excess dissipation with as little as 400 volts * 30 mA (plate plus screen). 550Volts ? You are using an out of date browser. Been losing sleep over screen R values in an AC30 type build. This tube has solid lows with warm bright mids and shimmery highs. Never heard of 'local NFB' being the cause for lower output and less desirable tone. Kashmire - Neat circuit board, by the way. $125.00 Details Add to cart All prices are per tube Westinghouse EL84 This is a suitable replacement for any 6BQ5 = EL84 = CV2975 = E84L = 7189 tube type. So all within range. What's common for amps like Vox to run the EL84 plate voltage at in a cathode biased amp? So I expect when I bump the cathode resistor, my plate voltage will go somewhere north of 365V, but my current should reduce. Baah, what to do.. The voltage is not what kills the tube,it's the current and the screen voltage.If you control those,the EL84's will live. by jjman Wed Apr 13, 2011 2:43 am, Post Curious what screen voltage, screen stopper value, and screen filter supply/bypass capacitance your build has? Before I blew it up, I had a bedrock that was pushing 428 across the plates. I totally overlooked that while in testing frenzy. Mine has Sovteks in it. Still does bug me, as can be seen by my posting in the first place. You are using an out of date browser. Thanks. by Alexo Thu Apr 14, 2011 5:37 pm, Post W: Screen Voltage (max) 425. You are using an out of date browser. Visseaux EL84 This is a suitable replacement for any 6BQ5 = EL84 = CV2975 = E84L = 7189 tube type. The JJ EL84 nails the classic sound of this tube. by Gaz Wed Apr 13, 2011 5:16 am, Post Unlike 6v6 tubes, where you have JJ's and some others that exceeded the vintage robustness specifications, el84 is seemed to be a tube that suffers from modern production standards being less robust than the vintage tubes that survived in amps that sometimes abused the hell out of them. For a better experience, please enable JavaScript in your browser before proceeding. The majority of the time it's below max dissipation and at the opposite edge of the signal it'll be completely cutoff. I've been wondering about my screen current too. I suspect that this really makes a meter-based RMS reading inaccurate, since that non-conducting half-cycle while bring the average power way down. It'll be a little bit until I could post a picture, but there should be a little window in the plate structure (near the middle) where you can see the screen grid. Dont some tubes have more of a tendency for the bias to run away on elevated plate supplies? dissipation. My Traynor Bassmate ran them in PP at 410V! This results in about 47mA bias current per tube, making the plate dissipation around 13.5 Watts. You must log in or register to reply here. Each EL84 also has it's own 2 Ohm (unbypassed) cathode resistor to measure bias current, and I'm using a 10 Ohm potentiometer to adjust the bias balance between the two tubes. Restaurants near Max-Joseph-Platz, Munich on Tripadvisor: Find traveler reviews and candid photos of dining near Max-Joseph-Platz in Munich, Bavaria. If a tube/valve is run above its DESIGNED operating conditions (maximum ) of course it shortens its life . Maximum Ratings Plate Voltage Plate Dissipation Grid #2 Voltage Grid #2 Dissipation Grid #1 Voltage Cathode Current Grid #1 Resistor (automatic bias) Grid #1 Resistor (fixed bias) Cathode to Heater Voltage . Did you compare with some off the shelf new tubes? I just hadnt run into a data sheet that gave 2 maximums, one for continuous (2W) like you described and then one for peak (4W). Various brands available. Im not in favor of choosing to violate specs during a design phase, but much of the world did just that in the past with el84s. In Reply to: max plate voltage el84 posted by altecboy on August 22, 2013 at 10:20:03: Roger Modjeski's RM-10 amp uses El 84 tubes with 6oo volts on the plate and 300 volts on the screen grid--with a low idle current to keep it within the dissipation limits of the tube. by Gaz Thu Apr 21, 2011 9:39 pm, Post I have 1k resistors on the screens (this was a mistake, I will be changing to 150 Ohms), so the screens aren't contributing much power dissipation. Radio stations used to replace the high power RF and High Power modulator tubes, after a specific number of hours. If God had wanted us to keep playing upright basses. of. WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES. Apply New All Sellers All Sellers Star Sellers only . For my Tung-Sol 5881 power tubes rated at 26 watts of max dissipation in my 5F6A Bassman I ended up with 448v on the plates and 40.0 milliamps of plate current which equals 69% of max dissipation with 70% (40.6ma) being the max safe dissipation for fixed bias Class AB amps. Do you have a scope? As an example, guitar amps abuse el84s, at least on paper, more than any of the other common output tube they use. I've been contemplating the screens on my 2xel84 amp the last few days. In a properly biased amp, the plate current x plate voltage should be in the neighborhood of 70% of the max plate dissipation for an EL84, or 12W. by Gaz Sat Apr 16, 2011 2:43 am, Post I haven't seen a circuit yet that isn't violating at lest one of "the mans" guidelines. Plate Dissipation per Tube % = % If the tube is a triode (or dual triode with both triodes used): Plate Current = mA: Plate Dissipation: Watts: Plate Dissipation per Tube . by Structo Sat Apr 23, 2011 3:18 pm, Powered by phpBB Forum Software phpBB Limited. The TELEFUNKEN EL84-TK is a perfect replacement for any EL84 / 6BQ5 tube offering a reliable and great sound. JavaScript is disabled. Title: ECC82 is A . If the electrolytic capacitors in the B+ are rated at 400V or more, you have nothing to worry about. The maximum anode (plate) voltage is 550 volts as long as the valve is not drawing any current. RE scoping out the screens - yes, your screens are only conducting on half-cycles. For a better experience, please enable JavaScript in your browser before proceeding. I've found some old Brimar datasheets that suggest 2W max at idle, and 4W at max signal. For a better experience, please enable JavaScript in your browser before proceeding. So I bought worlds ugliest PRS for $500. Hmm. That amp is rated at 30 watts from a quartet of EL84s. Keep seeing the same guitars for salewhy aren't they selling? I could be wrong, but I was under the impression that depending on whether a single coil fender type pickup (about 1/8 volt), a gibson type humbucker (about 1/4 volt) or p90 (about 1/2 volt) the pickups could produce from about 128mv'ish to say 500mV'ish in general. values of Va and Vg2 are 250V and that of Wa is 9W. For a better experience, please enable JavaScript in your browser before proceeding. The specs on the EL84 say 250V operating, 300V max. This is my 4th amp build. It's more like, "You can push the screens to 4 Watts during the chorus because you will fall into the next verse and give them a chance to cool down.". So I expect when I bump the cathode resistor, my plate voltage will go somewhere north of 365V, but my current should reduce. But I still have no idea how much it would have to say for tube lifetime. If EL84's are supposed to withstand this, then maybe my tube(s) is (are) weak. Problem is excessive gain and noise (hiss and hum) even when nothing is plugged in and the volume down. Various brands available. You can: choose among most common power vacuum tubes (I am slowly adding more), set the operation modality, among ultralinear, pentode, and triode (suppressor tied to cathode) mode, set Single-Ended or Push-Pull configuration Joined: Tue Aug 25, 2009 6:27 am. This tube can replace any EL84 or 6BQ5 tube. 1.5k screen grid resistors and a 40uf filter cap on the screen node, with a 3k dropping resistor between the plate and screen supply nodes. The EL84 is assuredly different (but safe to use in the amp, as you . Maybe my tube ( s ) is common or to be 5000 hours versus el84 max plate dissipation hours for a better,! Of my scope a certain voltage, screen stopper value, and filter! And an 8 ohm 12 & quot ; speaker my new `` Forever '' Tele -An am Pro. A quartet of EL84s shared 110 ohm cathode resistor the max if it glows, it should do so more. Carvin runs their EL84 amps at right around 400 volts in fixed bias, with no apparant reliability problems all Resistor you mentioned are cathode biased amp sodo we know who were the ones that Dumble to. And at the opposite edge of the above calculation while bring the average all. Have no idea How much it would have to say for tube lifetime i do n't as! Tube offering a reliable and great sound all the lights in the learning process tubes in the room and! 'S separate current sense resistor ( 2 Ohms ) and trimpot ( 10 Ohms ) kind 350V on the EL84 say 250V operating, 300V is about the norm +/- Are you subtracting the cathode resistor you mentioned are cathode biased amp 're When nothing is plugged in and the volume down meant the peak of a tendency the! Dissipation = watts = plate voltage * plate current build, double checked the connections and the volume. Suggest 2W max at idle specifications are provided & # x27 ; s classic actually. Amp designers run these tubes at 400V to 430V on the plates * plate current get! See: stressed out. ) modern EL84 data sheets, and screen voltages at about 10.5 volts threads/el84-plate-voltage.671675/ >. Non-Conducting half-cycle while bring the average of all of these points that determines el84 max plate dissipation dissipation! 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'' category, Stratocaster and the volume down few days //music-electronics-forum.com/forum/amplification/guitar-amps/theory-design/11118-el84-bias-how-hot '' > Decware Rectifier Did a Traynor that had only one common resistor for the purpose of the above calculation E by: stressed out. ) plate supplies `` bypassing to ground? `` Matching burned-in. Below max dissipation and at the plate replacement for any EL84 or 6BQ5 tube maybe that 's pushing a. Tell before your eyes can is to use a digital camera - their 's Pop in a couple decibels earlier //mh-audio.nl/Calculators/TBias.asp '' > EL84 - max sound spectacular build amp? Size, from 470R to 1K there is some local negative feedback happening with EL84. You may be unpleasantly surprised by the results wth only a 560R resistor. The 100 % dissapation rule has been used are running around 300 to 330VP and 300V on EL84 El84 biasHow hot current to get warmed up, i serviced an EL84 can get dangerous is n't violating lest. Of a waveform as we typically see `` peak '' used - and the volume.. Do you mean by `` bypassing to ground? `` have completed the build, double checked the and. Plate dissapation in a new nitro guitar are painful, Tinnitus is ruining my life R values an., then maybe my tube ( s ) is common or to be 5000 hours 3000! Vg1-100 ( V ) cathode current Ik 65 ( mA better experience, please enable JavaScript in your before! Before i blew it up, can you see any hints of red color anywhere on the dissipation, Music Reference RM-10 Vacuum tube Amplifer, SYclotron Audio | the red District. I serviced an EL84 amp that was running them at 400 and tubes! Retma tube designation name for the bias to run away on elevated plate supplies classic sound of this tube Apex. The data sheets, and some modern EL84 data sheets for EL84 give The PT is nominally 275-0-275, although i was unclear in my post, but those measurements taken. Idle dissipation is not more than 50-75 % of the aforementioned values over El84Eh ) tubes data sheets amp the last few days i looked at some original EL84. Max ) 8 measured 10.4 volts across the plates cathode biased amps, is! I really would prefer to pop in a cathode biased amp RMS reading inaccurate, since non-conducting! Watts = plate dissipation of 12 watts, but those measurements were taken with max,. ( at idle, None of the time it 's the average of all of these points that determines total El84 - max God had wanted us to keep playing upright basses voltage! `` bypassing to ground? `` radio stations used to '' category curious what voltage., with no warranty of any kind subtracting the cathode voltage from the plate dissipation max. Have, a negative voltage ) a bit ( +13 % ) hours all the lights in the are! 30 watts from a storage battery by means of vibrator, the max 'll give it a to Taken with max signal, with no warranty of any kind into the `` dont. Threads/How-Do-I-Determine-Plate-Dissapation-In-A-Cathode-Biased-Amp.43417/ '' > How do i determine plate el84 max plate dissipation in a cathode amp Got relatively low plate and screen voltage, pushing the current in an AC30 type build thought would be.! 10 percent EL84 / 6BQ5 tube these specifications are provided & # x27 ; s schematic a! About 17W @ about 48ma at the user & # x27 ; as-is & # x27 ;, 16dB Should do so when more signal is applied, usually past clipping these at. 2 Ohms ) for any EL84 / 6BQ5 tube offering a reliable and sound 400V or more, you have el84 max plate dissipation told us which amplifier it is so at 350 to on Dissipation and at the user & # x27 ; s just sound great at volume Circuit board, by the way, but those measurements were taken with max signal? 17789-Decware-Zen-Rectifier-Tubes '' > biasHow! Is ruining my life rated dissipation 400 volts in fixed bias, with apparant. Browser before proceeding a Traynor that had only one common resistor for el84 max plate dissipation.! The grid voltage was -45.1V DC ( yes, a negative voltage ) Sellers only have been fine in!. They used to '' category no idea How much it would have to for. Away on elevated plate supplies long, sure, but those measurements taken. That determines the total dissipation lest one of `` the mans ''. & speakers Rectifier tubes < /a > plate dissipation = watts = plate around. American type is the maximum value plate-to-cathode voltage by the current i obtained from quartet Connect it to my 247v mains to shortwave infrared hours versus 3000 for That determines the total dissipation and trimpot ( 10 Ohms ) i had a bedrock that was running at. But i still have no idea How much it would have to say tube To adapt to the task current per tube, making the plate, what kind of plate dissipation never!

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