Tube driver bias moderator

After youve completed the bias adjustment changes, it is a good idea to go back and check the bias measurements for all the other tubes since changes made to one tube could possibly affect the setting of all the others. Slow blues using a dumble amp sim and tube driver sim. This is the ultimate bias model inspired by requests from eric johnson in 1985. But the theory is that the next time you need tubes you can order the same set from the tube company and they will bias properly in your amp without changing the adjustment.

Those same sessions also resulted in the division bell companion album, pink floyds the endless river, which was not completed until 2015. Start of by getting a weber bias right weber bias right all you do is insert the device into one of the power tube sockets and then plug the tube into it. Positive grid bias and jamup pro xtdumble with tube driver. Ok, so all tubes, to hit their optimal tone and operation, need a certain amount of current. Weber speakers homepage loudspeakers, components, and equipment for the vintage musical instrument enthusiast. I bought the newer 4 knob version used with the adjustable bias control. Heres your chance to own this legendary holy grail of overdrive pedals. Here is a walk through of how i get an eric johnson inspired lead tone. The driver circuit is basically just a normal grounded cathode stage but with a beefy tube and a pretty high idle current and therefore low output impedance which is needed to drive the tank. Pushpull output stages can be configured with bias and balance controls see figure 2a, or independent bias controls for each tube see figure 2b. David gilmour has been an avid tube driver user since around 1993.

Your tube amplifier can easily complement circuits purely analog, allowing for fully automatic bias control and get rid of the repeatedly adjustments of end stage which is. Please, follow these basic instructions to place your order. What about these tube companies that say if you use their tubes you wont have to rebias your amp. The output stages of most music man amplifiers fall into these two camps, distinguished primarily by the type of output driver circuit they use. Its not the only way to bias your output tubes, but i think its the safest and easiest method. In these calculations, 5% of the cathode current is assumed to be screen current. Tube driver new direct from bk butler with bias covid. Whenever in doubt, ask a professional for help and avoid any risks especially if your amp doesnt give you such easy access to bias points and trims. However, remember that tubes are hugely outdated technology only made in a few places in the world now and so they are highly inconsistent. Im biasing the 6l66v6 tubes in a vintage sound amp. Nathan brings a lot to the table when it comes to pickup design and manufacturing. This allows you to monitor the plate voltage and the cathode current.

The les paul ga 40 is 1 of them, it uses a 6sq7 for the lfo, but i know that ive seen a later model or 2 with a 12ax7 for the lfo. A failed biasing component that lets the grid assume the same voltage as the cathode will cause an output tube to act almost shorted. General knowledge of vacuum tubes, like from my article whats inside vacuum tubes ok, now say all. This is the only handmade and authentic tube driver. Im not preoccupied by achieving an exacting recreation of his tone, but one that works for me and my rig. Bk butler tube driver 5knob demo original bias mod vs diy bias. Nowadays most cars have complex computers that control the idle, however, in the end. Known the world over for creating the eric johnson violin tone and as one of two main pedals used by david gilmour. Which one is the newer tube works tube driver reissue. This saved him from sorting through literally hundreds of tubes to find the exact one he wanted. The knob is attached with duct tape temporarily, i drilled a hole later.

The bias controls the current that flows through the tube and defines the quiescent point of the tube, so that the tube reacts immediately to an input signal and so that it amplifies that signal accurately. Plate voltage dc voltage measured between plate and cathode. Discussion in glowing bottle tube amp forum started by teleblueman, may 18, 2017. The tube king is reputed to be a very similar circuit design to the tube driver and the patent there certainly backs that notion up. Of course, the wvpower mk2 has truly symmetrical and unbalanced inputs. They say the trem is very strong sounding on these. The model is the vintage 15 which does not require me to open the. Waversa wvpower mk2 mono power amplifier 300b dealer ad. This article describes the most common methods of obtaining negative bias voltages in vaccum tube circuits. Each one is hand made and checked out carefully by bk himself. The 500 ohm resistor red arrow connected between the cathode and ground, controls the current flow through the tube, thereby setting the bias. An amp like the elekit tu8340vk is also a fixed bias design but a microprocessor reads some voltages and adjusts other voltages to set the bias. A tube amplifier chassis contains lethal high voltagesometimes over 700 volts ac and 500 volts dc.

He first used them in the recording sessions for pink floys division bell album. Nobsound vacuum tube amp amplifier plate bias current probe tester 8 pin socket for el34, kt88, 6l6, 6v6, 5881, 6550, kt66, kt100, kt120, 7027 ct1p, plate current 3. Ive heard the prototype of the amp and it is nothing short of stellar. Nathans topic is on how to do your own tube biasing at home. You can also use individual cathode bias resistors on each tube. Special 5th knob bias mod information butler audio. If they are biased incorrectly or if there is a fault in one of the biasing components, it can cause a number of power supply and output section problems. How to set up my audio interface with bias fx amp pedal desktop. This is a very basic guide for checking the bias of a tube amp. I wouldnt say it sounds muddy in any position but it has an effect.

How to bias your tube guitar amplifier regis coyne. An lcd screen shows the current status of the output tube, driver tube 6h30pi and the current setting of the output tube in realtime. An accurate bias meter for tube output stages audioxpress. Output tube biasing, an introduction wall of sound. David gilmour, joe satriani, billy gibbons and many other pros now use the bias mod. To quantify the dynamics of overdriving a guitar amplifier we can use three measures. Hi andrea, i have the bk butler tube driver with bias mod as well, i use a nos yugo real tube tho 12ax7. Beware of inferior clones and used worn out pedals. The tube driver is capable of a plethora of sounds and the bias knob expands those possibilities. Tube driver with bias control original design by bk butler. Tube driver bias with yugoslavia 12ax7 and tube driver chandler sylvania jan 12au7. The other common type of output tube biasing is cathode bias. Prior to setting up, please refer to the manufacturers website of your audio interface.

If you are uncertain that you are experienced enough to work on a live high voltage amp, please take your amp to a professional to get it biased. There are always exceptions and with many different amp types, these instructions may vary. You can add individual 1 ohm resistors from the cathode of each tube to the common bias resistor, but you must then measure across the 1 ohm resistors, not from the cathodes to ground, to determine the voltage drop, and thus the cathode current. Bk butlers original hand made tube driver guitar pedal used by eric johnson, david gilmour, billy gibbons, joe satriani, kenny wayne shepherd. Although the pedal was designed around a 12ax7 so keep that in mind, and you mentioned you have the bias knob version so that adds. Output tube biasing, an introduction part 2 wall of. Tentlabs negative bias supply designed in cooperation with menno vanderveen, we are proud to announce a new module when using fixed bias in your amps, the currents need constant readjustment to compensate for mains variations and tube aging. A good analogy from the automotive world is the idle speed of a motor. The operating point of a device, also known as bias point, quiescent point, or qpoint, is the dc voltage or current at a specified terminal of an active device a transistor or vacuum tube with no input signal applied. Butler tube driver with bias mod at the best online prices at ebay.

Essentially, you want to bias your amp such that the plate dissipation rating of the output tubes is not exceeded. The tank is coupled via a coupling cap to prevent dc current from flowing through the driver coil. Still paid a bundle for it, but as mentioned the eq section gives it a lot of range. I bought a bk butler tube driver 5 years ago with the intention of swapping out the stock tube. Ive just opened mine up and the circuit board quite clearly reads patented. Before we talk about different types of biasing found in tube amps, it is probably a good idea to explain what exactly the bias is. A bias circuit is a portion of the devices circuit which supplies this steady current or voltage. It might not be identical to the tube driver but its in the same sort of area. Compatible with all electric guitars and amplifiers.

Often it is a switch that can select bias for el34 tubes, or 6l6 tubes depending which is installed. The et pro one bias probe is calibrated at 180 milliamps to plus or minus one tenth of one milliamp at 700 volts dc, so unlike other probes on the market the et pro one can be used on amps that exceed plate volts. This is the version with the optional 5th knob a bias control, to change how the tube behaves. Adjust the setting of the bias to the proper range, i. Chandler tube driver vs tube works 911 telecaster guitar. The best way to understand bias is to think of it like the idle setting on a car. A general rule of thumb is that class ab amplifiers are usually operated at no more than 70% of the maximum plate dissipation of the tube to account for the higher dissipation that occurs under signal conditions, while true class a. Tube bias control and get rid of the repeatedly adjustments of end stage which is necessary due to aging tubes. By owning a bias probe youre not at the mercy of a tech anymore and you are now in control of your tone.

Im here asking this question because i dont know what i dont know. Add only the numerical characters of the item number. The custom variable bias mod version is available with an additional custom 5th control ive made several of these for eric johnson, david gilmour, billy. As it takes less to overcome the signal the earlier in the tube chain you go. Negative grid voltage inhibits current flow through the tube. If you have not been trained to work with high voltage then have an amp technician adjust the amps bias. Some outdated interfaces dont have the latest driver to run on newer operating systems such as os x 10. Before talking about how to bias tube amplifiers, i will briefly explain the difference between hot and cold bias. I find the lovepedal dover drive gets me close enough that i dont often pull out the butler. The bias control is very helpful as it adjusts the amount of current applied to the cathode of the tube.

Both the wvpre and wvpower 300b monoblocks utilize fully balanced internal circuitry and therefore balanced interconnects are recommended. Posted on 20170905 by steve graham in amplification, tubes 19 comments. As you reduce the bias, you get less gain but also a spittier sound and a much looser bottom end. Cathode current milliamps displays approximate plate current after calculation. In fact, go to randys site and read all the tech stuff there. Hot bias means when you bias tube amplifiers with more idle current than the optimum. Biasing an amp requires some knowledge of tube amp circuits and experience with high voltage. Id like to have a transistor or a pair of transistors directly drive the grid on the output tube, without need coupling capacitors. Any good step by step instruction for biasing a tube amp.

Thus, turning the bias pot so as to make the bias voltage less negative will have the opposite effect and will increase the idle current. Your post will require moderator approval before it will be visible. I have a current bias knob tube driver and share the above sentiment sounds great, but big and the power supply is a pain. I just bought a deluxe reverb reissue, and you can do it very easily. To the best of my knowledge, this arrangement for measuring bias is unique. I think the db prefix stands for driver bias and indicates a solidstate phase splitterdriver circuit is used. These are still fixednonadjustable bias amps as there is no internal bias trimmer pot to fine tune. Chandler tube driver vs tube works 911 discussion in the stomp box started by winny pooh, mar 17, 2006. The bk butler comes as a tube driver model and is available with a bias knob for 12ax7, 12at7, and.