You can run the tube as high as 85% but you will wear them out quite a bit quicker. If you are trying to bias 6550s at 70% plate dissipation you're actually asking the amp to dissipate 49 watts at idle. . A Milliamp reading is more accurate because the screen current is not added to the plate current as with other probes that measure in Millivolts. Last edited by andyhatescrass at Oct 29, 2012, 1:52 PM. In my case, the plate voltage is 450v (as displayed) and the tube dissipation is 23 watts (from the specs), and so [23 / 450] * .7 = 36ma. It's in perfect shape never gigged and only used in a smoke free home. Adjusting the resistor set the bias for all four of the power tubes. I recently added a little tolex covered V-Type to my collection. Also included is a Eurotubes BIAS probe if you ever want to upgrade the power tubes. Resistance from OT to V6 pin 7 is 75.6. The easiest solution is to install 10 Ohm 1 watt resistors in each tube cathode from the cathode to ground. I won't quote the EuroTubes instructions again. Weber Bias Calculator Eurotubes has a bias probe and multimeter that can give you the plate voltage and bias current in a single probe. 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 .7 will just get you out of crossover distortion and you can go as high as .85 percent but you will wear out the tubes quicker! So for 6L6, 30 watt tube, in an amp with 400 plate volts, would be; (30 x 0.7)/400 = 52 mA per tube. If the bias probe breaks the circuit at the plate connection and inserts itself there you will read plate current directly without any screen current. Here's a bias calculator to help you bias those 6L6"S" tubes. Bias Calculator - Granger Amplification trend grangeramp.com. This looks like the 6L6GC, but who knows? The Eurotubes "Pro One" Bias Probe is an "all in one" bias probe for octal tubes including 6V6's, 6L6's, KT66's, EL34's, E34L's, KT77's, 6CA7's, 6550's and KT88's. It is unique in the fact that it shows you both the plate current and plate voltage simultaneously and it is completely self-contained with no switches, knobs or batteries. 6÷327=.0183 so 18.3ma current Tube #2 had 304ohms resistance. I am not familiar with the Eurotubes bias meter. . I bought the eurotubes bias meter. This could be what this tube is. Thanks Share Reply Quote. Those sound like SED Winged C EL34s which are really good tubes. The idea is to calculate what your ideal bias setting should be then after measuring the bias of each tube to find out which one is running the hottest (highest bias current) set that hottest tube bias to your calculated reading and your tone should be good & also ensure none of your tubes are running too hot, as the other 3 tubes should be . 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 . This may not be the case for all of them but peavey now builds in china so QC should be subject to scrutiny. Resistance from OT to V7 pin 7 is 61.7. Bias the amp to whatever point sounds good to you. Each tube in this comparison was installed in the same custom-built, fixed-bias single-ended guitar amplifier in order to obtain the voltage gain measurements and conduct listening tests. How many milliamps should a 65 DRRI be drawing? Ideally, your tubes will be matched within 5mA for EL34's. 2.Very, very few product amps use individual bias, you have one bias pot to bias all 4 tubes. Some old schoolers don't think much of the bias probe method but we can tell you from experience that it not only works but it works very well. With a voltage drop of 3, I did his calculations (voltage drop / ohms) V7 is 3/61.7 = 48.62mA. I set the bias calculator to EL84 tube type, entered 354 plate voltage. best www.amazon.com. Eurotubes suggested me to use their Bias Probes (Eurotubes - Bias Probes for vacuum tube valve amps!) 6L6GC Comparison of Current Made Tubes. Currently unavailable. okay sorry guys for asking too many questions about tube amplifiers (I'm really getting anxious with the tubes replacement ideas). You need to know where the bias pot is located. Changing the tubes of a Marshall JCM900 (EL34) Tubes are easy to change but you absolutely need to bias them once installed (power tubes). The only 6L6 types that I can find on the Eurotubes (JJ importer) website are a 5881 and a 6L6GC. The higher the current the lower the plate voltage and vice / versa. REplace R52 with something like 3k to 5k. The Eurotubes Octal Bias Probe measures in DC Milliamps and will work with any Multimeter that can read in DC Milliamps. . You can be more accurate and measure just the plate current with a different method. Then, go to the web page above and select the tube type. Retube™ Kits For Budda. it'll get closer and closer every time. Solving for current, current = power/volts. Take a reading at the R35, R36 junction to see what the bias voltage is. The Eurotubes site clearly states: #2. Here's a bias calculator to help you bias those 6L6"S" tubes. I was looking at the grid leak resistors when I wrote 220k Ω, it's actually a 250 Ω 10W resistor. The BiasMaster is available in an octal and noval version. The bias probe is placed into one of the amp's power tube sockets and the tube into the bias probe. They show a bias voltage of -63V with a 120VAC line voltage. Really kinda frustrating. Biasing your amp doesn't have to be difficult. If R52 is really low, then it doesn't do anything to the equation. Now, with the 158R resistor is 355Vdc. Tweet. However this does not mean you have to calculate them at 30 watts to get out of crossover distortion. 12 watts divided by 350 = .034 … Eurotubes Bias Probe for Octal Base Power Tubes. I have put several. We don't know when or if this item will be back in stock. Retube™ Kits For Bad Cat. Just that simple. Most bias meters measure both plate and screen current together. Then press calculate. It read 76'ish on each side. From what I understand the caps will kill you but a 500 volt shock will just hurt bad or burn ya. V6 is 3/75.6 = 39.68mA. I suggest you buy a multimeter and octal bias probe (the Eurotubes one is good for $28). You can see the bias probes Eurotubes makes here. He said that it's true that Rectos have a cold bias, but you must install a bias trimmer in order to get KT88's to work properly. 25 watts/425 volts = 59 mA. Octal socket pins 1,2,3,4,5,6, and 7 are wired pass-through. Videos 25 Watts divided by 450VDC = .0555 multiplied by .7 = .0388 and rounded off this would be .039 or 39 Milliamps. Talk about being the "real deal"; had the new set installed and the AB763 Twin biased and running aim less than 30 minutes using this nifty probe. I just checked my stock JSX bias at the test points and got a reading of 6mA (!). The bias on an amplifier can be adjusted by a technician to allow more or less current to flow. Luckily, of course, the difference is small. The squeal is at about 7250 hz. And then you swap the probe from tube to tube to check the bias off all four tubes. This looks like the 6L6GC, but who knows? This could be what this tube is. We will be using the 70% bias point. Solving for current, current = power/volts. Doesn't speak guitar . Join date: Dec 2009 . It has very low hours and doesn't get used much. Find helpful customer reviews and review ratings for Eurotubes Bias Probe for Octal Base Power Tubes. This is potentially more risky as the voltages involved are larger. You need to be able to find the anode plate voltage, in order to properly bias the tubes. It gave me 23.7 for 70% dissipation. Its a eurotubes bias probe. The Eurotubes "Pro One" Bias Probe is an "all in one" bias probe for octal tubes including 6V6's, 6L6's, KT66's, EL34's, E34L's, KT77's, 6CA7's, 6550's and KT88's. It is unique in the fact that it shows you both the plate current and plate voltage simultaneously and it is completely self-contained with no switches, knobs or batteries. In this video, we'll show you how to bias your tube amp using the TAD BiasMaster. Yes, that bias point may not be optimal from a crossover distortion perspective, but if that is the tone you like, set it there and enjoy. https://robrobinette.com/Tube_Bias_Calculator.htm First, put the bias probe in one of your 6V6 slots. Except of course you're actually measuring *cathode* current, which includes both plate and screen current. 05-30-2020, 05:58 AM. Read honest and unbiased product reviews from our users. You can use 70% of 25 watts and they will get a great warm clean tone well out of crossover distortion. Also you bias by current and voltage. For EL34 tubes with a plate voltage of 456.6V, we see our bias point will be 38.33mA. All explained in the sheet that comes with it, however (briefly) you divide the tube's maximum dissipation (in watts) by the plate voltage, multiply by .7, and that is your target for the bias. Since I like to run my gear pretty hot I will routinely bias them at 44mA in an amp that has 485 plate volts. On several of these 6050MH heads i've seen they are bias well in to the 90% range. Eurotubes 9 Pin Noval Bias Probe Brand: Eurotubes. It looks like I'll need to have the 65 DRRI bias when I put in the new JJ tubes. Well, before, with the 129R (measured) cathode resistor, the plate voltage (with the same wall voltage of 234Vac) was 349Vdc. My tubes are 6CA7 rated at 25 watts each. Changing the bias level can effect the tone. Subscribe to our channel for more videos, and leave us a comment below! Product information Feedback Would you like to tell us about a lower price? There are lots of ways to do this. As I remember, my EuroTubes probes showed about 425 volts. Yes, the plate voltage will vary a little with the bias. Either way I get 70% bias. 6L6GC Comparison of Current Made Tubes. Two 8 ohm output taps and one 16 ohm output tap. It gave me 23.7 for 70% dissipation. Browse these categories under "Full Retube™ kits for Guitar Amps". I would bias the amp to no more than 20-22 watts per 6L6GC. If your line voltage is higher, the bias will be off. The formula for biasing is the plate dissipation of the tube ( 14 watts for a 6V6 ) divided by the plate . As I remember, my EuroTubes probes showed about 425 volts. Resistance from OT to V6 pin 7 is 75.6. It doesn't have an HUGE impact on bias calculation, however I see your point, especially since the plate voltage is already on the high side. Around 40-70% dissipation is acceptable. Now I'm trying to set bias. at Amazon.com. Hullo people, I have a complete set of JJ Telsa's coming from Eurotubes.com. Like. That means you'll need to take measurements of your plate voltage with either a multi-meter or buy a bias probe. I installed a set of perfectly matched JJ KT88s from Eurotubes. I've read the article from Eurotubes before and asked about using Kt88's in a Dual Rec from a local tube wizard and importer. I don't want to test . but they don't know what value I should bias it up to. Not sure why some manufacturers bias so cold, other than to extend tube life. Used a few calculator sites.. 1. I typed a really long reply and lost it. I set the bias calculator to EL84 tube type, entered 354 plate voltage. On these amps, the bias is set by changing a resistor, R49, 75K ohm, in the early V4B. Fixed Bias, single trim pot. The ET "Pro One" Bias Probe is an "all in one" bias probe for octal tubes including 6V6's, 6L6's, KT66's, EL34's, E34L's, KT77's, 6CA7's, 6550's and KT88's. It is unique in the fact that it shows you both the plate current and plate voltage simultaneously and it is completely self-contained with no switches, knobs or batteries. Octal socket pins 1,2,3,4,5,6, and 7 are wired pass-through. Retube™ Kits For Blackstar. If you just want to bias this set of tubes, probably the easiest thing to do is to change the 470r resistor between the winding and the diode. . My tubes are 6CA7 rated at 25 watts each. Anyone tried biasing the unit and give me some insight please? For example, if you were biasing a 25 watt tube and your DC plate voltage was 450VDC the calculation would look like this. Cannot say enough good things about Eurotubes; best guys in the business. Hello, I have for sale a Blackstar HT20 Studio 20W combo Amp. You can also take off an approximate screen current figure which is another feature of Rob's calculator. Retube™ Kits For Bogner. Then, enter the plate voltage in the next empty box. The reason you can't get the bias into that range is that it's a Class AB amp. You're trying to bias it in the Class A range (BTW, it won't make it Class A). 60% is another common choice. I THINK I read my plate voltage as 504V I have a middle of the road multimeter which I can barely use ha ha and a new eurotubes probe. Just brought my DSL100HR home and put my DMM to the bias probes. Retube™ Kits For Bugera. 3.3k is a standard value, nothing cosmic about 3k exactly. Tube rated max watts, times 0.7, divided by the plate voltage, equal bias mA, each tube. I'm showing plate voltage at 448V and bias at 14mA. So 23.9ma bias current using the 1ohm resistors Then I used the output transformer resistance method Tube #1 ohms between output transformer center tap and pin 3 primary is 327ohms. Check the bias circuit components carefully. Since 2006 we have offered a single octal bias probe for use with a Multimeter. V6 is 3/75.6 = 39.68mA. The more current there is flowing, the higher the numbers will be on the Bias King and the hotter the . Gives a good visual as well as info written there too. Eurotubes Bias Probe $60 (Central Square ) pic hide this posting . 150. 25 watts/425 volts = 59 mA. So if I want 70% bias, it doesn't matter if I apply 70% to the 25 watts (yielding 17.5 watts), or if I apply 70% to the current (yielding 41 mA). I am familiar with the probe you have from Eurotubes. that said they are amazing amps and with a little tweaking should be . I feel the same way about getting a plate voltage reading using pin 3. Bias Probes - Eurotubes - Vacuum Tubes by JJ Electronic trend www.eurotubes.com. WIth the bais probe I got a reading of 25mA. This is the most accurate way of measuring bias current, and only takes a few minutes to properly bias an amp that has a fixed, adjustable bias supply. With a voltage drop of 3, I did his calculations (voltage drop / ohms) V7 is 3/61.7 = 48.62mA. 4. Just be very careful because you are dealing with high voltage. Location: AZ. . This is a common setting for the bias. It will take around 3 times to get it correct. Re: Silverface Bassman 100 power supply issue. For example, if you were biasing a 25 watt tube and your DC plate voltage was 450VDC the calculation would look like this. The Eurotubes Octal Bias Probe measures in DC Milliamps and will work with any Multimeter that can read in DC Milliamps. Alternative, you can use a BIAS PROBE or some such device that goes between the the socket and the tube. 7÷304=.0230 so 23ma current Some amps are modified to add a bias pot which makes setting the bias easier. 5. I seem to remember JJ having a plain Jane 6L6 a few years back. After you set the bias, play the amp for a while and re-check the bias for drift. Thats a fair difference! 402-395=7. And also that Eurotubes exaggarate the quality of JJ tubes alot! This will be my first time doing the bias for an amplifier. 5. I read on Eurotubes' Website that the plate voltage runs at about 450 and that a good rule of thumb is about 36-42mA. Bias Probes - Eurotubes - Vacuum Tubes by JJ Electronic hot www.eurotubes.com. 4. Retube™ Kits For Blackheart. Then you can calculate the dissipation of whatever amp you want, even if it doesn't have bias points. . I measured this when I set bias, using the eurotubes adapter, but they had you measure with tubes installed. The stock 20h. You could go to Eurotubes.com and watch their vid on how to bias a DSL100. 25 Watts divided by 450VDC = .0555 multiplied by .7 = .0388 and rounded off this would be .039 or 39 Milliamps. Resistance from OT to V7 pin 7 is 61.7. This will allow you to read the voltage across the resistor and use Ohm's Law to calculate the current flow. The cheapest solution. I guess you can consider them a 19 watt . It is the first thing I would buy for the amp. So I put my EuroTubes bias probe on one of the power tubes and it was reading 457 plate voltage. So, you use the probe with one tube, dial in the necessary voltage on the bias pot. But the individual dissipation was well below 50% of 76 mV. The only 6L6 types that I can find on the Eurotubes (JJ importer) website are a 5881 and a 6L6GC. 402-396=6. Hey. If you want to set an exact value for the bias, you need to iterate - check V, calc, set bias, check V, calc, set bias etc. But, it really doesn't need to be exact. Each tube in this comparison was installed in the same custom-built, fixed-bias single-ended guitar amplifier in order to obtain the voltage gain measurements and conduct listening tests. We've compared the two methods extensively and very much prefer the probe over the scope method, especially for guitar amps. It's been upgraded with Electro-Harmonix pre-amp tubes and sounds great. This creates a slight positive charge on the cathodes. In a fixed bias amp, a constant negative voltage is injected to the grids of the output tubes while the cathode is grounded to the chassis. This is the most accurate way of measuring bias current, and only takes a few minutes to properly bias an amp that has a fixed, adjustable bias supply. R45VT. Each tube sample used for comparison was chosen because it measured in the middle range of idle plate current draw at . Oct 29, 2012, 1:51 PM. Nobsound Vacuum Tube Amp Amplifier Plate Bias Current Probe Tester 8 Pin Socket for EL34, KT88, 6L6, 6V6 . Calculate the bias voltage thus: (R53)/ (R53 + R52) x -57v = bias volts. The number you get from the 70% calculation is a "rule of thumb", not an absolute. Each time you adjust you need to calculate the formula to get it correct. There are two 10uF/100V caps in the bias circuit, C15 and C23 that should be changed. .70 X 12 watts / divided by plate voltage will get you the current setting you need. To calculate your bias you can measure the DC plate voltage from pin #3 of any power tube to ground using a multimeter but these amp are right at 400 and you can use this voltage to calculate the bias without measuring it if you wish. In a cathode-biased amp, the grids are grounded through a grid return resistor and a resistor is placed between the cathodes and ground. The octal and noval probes are also sold separately so that you can bias amps using EL84s, 6L6GCs, EL34, 6V6GT, etc. In the case of your amp, the results will show up in the "Class AB fixed bias" row. So if I want 70% bias, it doesn't matter if I apply 70% to the 25 watts (yielding 17.5 watts), or if I apply 70% to the current (yielding 41 mA). I already switched the switch to 6l6 inside the amp. P = I × V. P is the power rating of the power tube, I is the bias current, and V is the plate voltage of the power tube. Take the plate voltage reading you get from the probe and then do the bias formula: Wattage of tube divided by plate voltage multiplied by .7 for 70% idle dissipation Many people bias amps by ear, only using the meter to make sure it's not set too hot. Hendyamps. They basically tell anyone that asks for the proper settings to take it to a licensed tech for service. I would like to learn how to bias my own amp. Either way I get 70% bias. I seem to remember JJ having a plain Jane 6L6 a few years back. Correct, the EuroTubes bias checker measures actual DC voltage (pin 8 is ground) and only for the tube that's plugged in. You need to turn the bias down in order to raise the idle current (down is up for bias today). The purpose of this thread is going to be for discussing Mods to the jet city 20H, or any other topic pertaining to the JCA model 20H. I have a 65 DRRI made in the USA in 2003. Also from Bob at Eurotubes: "The bias is adjustable on these amps and for all you guys asking "Where's the trim pot?" here are a couple pic's. My recommendation is to use a bias probe to set the bias and anywhere between 36 to 40mA per tube is very nice. Retube™ Kits For B52. You can always adjust the setting in the future so if you are unsure, 70% is a good choice for now. Also, the stock amp has no means to measure the bias. I hate getting shocked. Each tube sample used for comparison was chosen because it measured in the middle range of idle plate current draw at . The instructions explain how to figure out the best bias setting for your amp. Correct mew if I'm wrong, but can a matched set of power tubes be replaced with another matched set of the same kind (6L6, EL34, 6V6) with the same ratings but made. I read about the test points on Eurotubes.com and have jsut confirmed that they are not that accurate, assuming that a bias probe is the accurate way. 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. Orange doesn't offer much help either. The bias setting will affect the cathode current. The amp is a push-pull, Class AB1 amp. The 2204 is a 50 watt amp. The stock 20h is a 2 el84, 3 12ax7 amp featuring a soldano slo Treble, Middle, Bass tone stack with a Presence control in the Power Amp. Just scroll down to the section: 10th July 2013 #2. I've raved here about how great it is to fit 1-ohm resistors between cathode and ground to directly measure plate current in fixed-bias amps. Picked the bias probe up to bias a new set of Eurotubes JJ tubes for a '65 Fender Twin RI. The Bias King is a simple, effective, and accurate diagnostic tool designed to read the current flowing through the tube of an amplifier (bias). When I go above 14mA I start to get a high pitched oscillating or squeal. I guess you can consider them a 19 watt . So I'm not sure if I need to pull the chassis and measure plate voltage the . The bias probe is placed into one of the amp's power tube sockets and the tube into the bias probe. Retube™ Kits For Ampeg. I hooked the amp up to my Captor X as a load, and then Focusrite interface to see what was going on via Arta. I dunno how well you know tubes / bias and such but they really should be around 70%. This calculator uses the power equation. Then it was a formula like tube watts (25) /pin 5 volts • .70 for bias amprage troyAmpallen , Mar 20, 2019 This probe measures in DC Milliamps and will work with any Multimeter that can read in DC Milliamps More accurate because the screen current is not added to the plate current . A Milliamp reading is more accurate because the screen current is not added to the plate current as with other probes that measure in Millivolts. Have bias points know what value i should bias it up to consider. Plain Jane 6L6 a few years back | Ultimate Metal... < /a > 4 run. Tube and your DC plate voltage was 450VDC the calculation would look like this four tubes threads/can-i-rebias-my-deluxe-reverb-rsissue-by-ear.162558/ '' > i. Bias Tool and Similar Products and Services List... < /a > Eurotubes probe... ] Retubing my Orange Rockerverb course, the bias circuit, C15 and C23 that should changed! As well as info written there too Eurotubes exaggarate the quality of JJ.. Cathode * current, which includes both plate and screen current together also that Eurotubes exaggarate the quality JJ! Rounded off this would be.039 or 39 Milliamps after you set the bias easier i buy! The 70 % calculation is a standard value, nothing cosmic about 3k.! Want, even if it doesn & # eurotubes bias calculator ; s been upgraded with pre-amp... Tone well out of crossover distortion i won & # x27 ; t have bias points cathodes and.! A cathode-biased amp, the bias for all four of the power tubes and sounds great tubes Asylum < >! $ 60 ( Central Square ) pic hide this posting to ground when i in! Measuring * cathode * current, which includes both plate and screen current together the easiest solution is install... Technician to allow more or less current to flow with Electro-Harmonix pre-amp tubes and it reading! This posting they really should be around 70 % is a & quot ; tubes > Check bias... Not be the case for all four of the power tubes and it was reading 457 plate voltage and /. 85 % but you will wear them out quite a bit quicker crossover distortion thing would! Brand: Eurotubes bias setting for your amp doesn & # x27 ; t offer help... But a 500 volt shock will just hurt bad or burn ya in each tube sample used comparison. Haze15 bias Noob - Check my Math of -63V with a little with the probe. Anything to the bias, play the amp for a 6V6 ) divided by plate voltage at 448V bias... Buy a multimeter and octal bias probe ( the Eurotubes instructions again looks! Is available in an amp that has 485 plate volts know where the bias for.. Each tube sample used for comparison was chosen because it measured in the bias for all four tubes Base tubes. With Electro-Harmonix pre-amp tubes and it was reading 457 plate voltage at 448V and at. Current and voltage watt tube and your DC plate voltage the 3k exactly our.... Is higher, the bias circuit components carefully of -63V with a voltage drop of 3 i... Noval version to extend tube life get closer and closer every time tube! Have offered a single octal bias probe $ 60 ( Central Square ) pic hide this posting multiplied! A different method DSL100 to to know where the bias for an amplifier be... I will routinely bias them at 44mA in an amp that has 485 plate volts ya... Amp biasing - Check my Math just hurt bad or burn ya the web page above and select the type! T=28747 '' > can i Rebias my Deluxe Reverb Rsissue by Ear Eurotubes bias probe for with...: //www.amazon.ca/Eurotubes-Bias-Probe-Octal-Tubes/dp/B019PAVXPG '' > 45 watt Super Reverb bias setting will affect the current... The probe with one tube, dial in the New JJ tubes alot that Eurotubes the. That should be go to the web page above and select the tube high... Current probe Tester 8 pin socket for EL34 tubes with a voltage drop / ohms ) V7 is 3/61.7 48.62mA... 39 Milliamps Jca20H Mod thread and owners club that asks for the amp for a 6V6 ) divided plate... //Www.Audioasylum.Com/Cgi/Vt.Mpl? f=tubes & m=253670 '' > what do you bias by current and voltage setting will affect cathode... Probe for use with a voltage drop of 3, i did his calculations ( voltage drop of,. ) | Ultimate Metal... < /a > now i & # x27 ll! And Services List... < /a > Tweet Products and Services List... < /a >.. While and re-check the bias pot is located 50 % of 25 watts each //forum.seymourduncan.com/forum/amplifier-central/140450-my-bias-is-fixed-so-when-i-go-to-change-my-tubes-next-year '' > Mod! Slight positive charge on the bias circuit components carefully on one of the tube type, entered 354 voltage... To V6 pin 7 is 61.7 plate dissipation of the tube type calculation is a push-pull, Class AB1.. Already switched the switch to 6L6 inside the amp plate dissipation of the tube type, entered 354 voltage. Current setting you need Class AB1 amp //www.harmonycentral.com/forums/topic/1305501-bias-probe-instructions/ '' > bias probe $ 60 ( Central Square pic. Thread and owners club amp that has 485 plate volts anyone that asks for the amp no. Amp, the difference is small ( Central Square ) pic hide this posting and the hotter the a pitched! Formula to get a high pitched oscillating or squeal tubes Asylum < >! Have to be difficult socket pins 1,2,3,4,5,6, and 7 are wired pass-through installed a of... A set of perfectly matched JJ KT88s from Eurotubes of thumb & quot ;, not an absolute an. A href= '' https: //www.listalternatives.com/tube-amp-bias-tool '' > how to bias my own amp it looks like i & x27... 6505Mh problem C23 that should be and re-check the bias calculator to help you bias those 6L6 & quot rule! Long reply and lost it 65 DRRI be drawing 2006 we have offered a single octal bias probe on of... Positive charge on the bias circuit components carefully suggest you buy a multimeter Oct 29,,! China so QC should be subject to scrutiny the 6L6GC, but who knows QC should be to... On these amps, the bias down in order to properly bias the amp Harmony Central < >... 448V and bias at the test points and got a reading of 25mA pic hide this posting cathode! Basically tell anyone that asks for the proper settings to take it to a licensed tech for service AB1.... Hours and doesn & # x27 ; s not set too hot amplifier can be more accurate and measure the! Drri bias when i put in the middle range of idle plate current draw at a plain Jane a. Guitar < /a > now i & # x27 ; s a bias to. Biasing the unit and give me some insight please through a grid return resistor and a resistor placed... Grid return resistor and a resistor is placed between the cathodes and ground sure Why some bias... A bias voltage of -63V with a different method can not say good. Pre-Amp tubes and sounds great: //www.amazon.ca/Eurotubes-Bias-Probe-Octal-Tubes/dp/B019PAVXPG '' > tube amp bias and! Your Marshall DSL100 to be subject to scrutiny read honest and unbiased product from... For service me some insight please this is potentially more risky as the voltages involved are.! Noval version the higher the numbers will be off low, then doesn. And it was reading 457 plate voltage of 456.6V, we see our bias point will on! Voltage in the middle range of idle plate current draw at high pitched or... The higher the numbers will be back in stock careful because you are with. I will routinely bias them at 44mA in an amp that has 485 plate volts of course, the.! 6L6Gc comparison of current Made tubes them out quite a bit quicker that. The equation at the test points and got a reading of 25mA to change my tubes 6CA7! Measured in the early V4B t get used much i just checked my stock JSX bias at 14mA how! Oct 29, 2012, 1:52 PM a 65 DRRI be drawing eurotubes bias calculator Central < /a > 1 mV... 6L6Gc, but who knows cathode * current, which includes both plate and current... Bias so cold, other than to extend tube life //www.harmonycentral.com/forums/topic/1324174-what-do-you-bias-your-marshall-dsl100-to/ '' > what is tube amp?! King and the hotter the of 6mA (! ) https: //www.vai.com/forum/viewtopic.php? t=27849 >. Bad or burn ya two 8 ohm output tap little tweaking should be subject to.!: //www.amazon.ca/Eurotubes-Bias-Probe-Octal-Tubes/dp/B019PAVXPG '' > 6L6GC comparison of current Made tubes product information Feedback would you like to us! For more videos, and 7 are wired pass-through caps will kill you but a 500 volt shock will hurt... And doesn & # x27 ; m showing plate voltage in the next empty box bias probes chosen it! > 4: //www.lespaulforum.com/index.php? threads/can-i-rebias-my-deluxe-reverb-rsissue-by-ear.162558/ '' > want to change my tubes... do i need to calculate formula. Sevenstring.Org < /a > 4 and screen current and voltage bit quicker my DMM to equation. Will vary a little tweaking should be subject to scrutiny 75K ohm, the... ) V7 is 3/61.7 = 48.62mA for all of them but peavey now builds in china so QC should subject! ) | Ultimate Metal... < /a > Check the bias probes ever want to upgrade the power tubes current. Anything to the bias setting than 20-22 watts per 6L6GC idle current ( down up... Have a 65 DRRI Made in the middle range of idle plate current with a.... Difference is small the anode plate voltage the current probe Tester 8 pin socket for EL34,,! My tubes are 6CA7 rated at 25 watts and they will get you the current setting need... Amps - Harmony Central < /a > 4 the Les... < /a 4... You but a 500 volt shock will just hurt bad or burn ya and the hotter the ; do! Bias?????????????????. Get you the current setting you need to be difficult or if this item will be my first doing. This would be.039 or 39 Milliamps and leave us a comment below biasing a 25 tube!
How To Setup Philips Hue Bulb Without Bridge, Victoria Island Cities, Crossword Clue Find 6 Letters, Plant Disease Forecasting Methods, Tung-sol 12ax7 Vs Jj Ecc83s, Highcrest Academy Sixth Form,