Kit’s Secret Guitar, Gear, and Music Page
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Copyright Kit Rae.
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BK BUTLER REAL TUBE OVERDRIVE - The Tube Driver is a booster/overdrive pedal with a simple vacuum tube driven preamp circuit inside, used by David Gilmour of Pink Floyd, Eric Johnson, Billy Gibbons, Joe Satriani, and other top guitarists. It was designed and built by B.K. Butler. Mr. Butler is primarily a home and car audio premap specialist. Around 1978 he desgned and began making an early version of the Tube Driver, one of the first tube overdrive pedals. It has evolved over the years into this current version. It generates a smooth light drive/boost tone and a killer heavy overdrive. It is not very versatile sounding on many amps, is very expensive, and some people find it very finicky and hard to get along with, but in the right setup, with the right amp, nothing sounds quite like it. The TD has a very unique voice that I have never heard another overdrive replicate. It features a master volume, hi (treble), Lo (bass), and drive controls, allowing for a wide variety of tone colors.
I think the TD sounds best with clean, vintage style Fender tube amps with lots of head room like the Twin Reverb. Hiwatt amps like the DR103, or similar amps like the Reeves Custom 50/100 are also very compatible with the TD. Amps that do not have a lot of head room, or break up easily with volume, do not play well with it, especially with high drive settings. It also does not sound good when a lot of buffered pedals are in the signal chain before it. However, for that Pulse and On an Island era David Gilmour light drive tone with a Hiwatt or Reeves amp, this is your pedal. It replaced the Colorsound Power Boost David used in the 1970s and Pete Cornish ST-2 Booster (Power Boost clone) from the late 1970s, and remains his primary overdrive. You can hear this pedal's light drive tone in songs like Coming Back to Life, Marooned, A Great Day for Freedom, and the live versions of Shine on You Crazy Diamond from Pulse. It was also used to boost/color David's Big Muffs for the Division Bell and On an Island tours.
David used two BK Butler/Chandler Tube Drivers in his 1990s Division Bell live rig, shown above. One was used for a clean drive/boost tone and the other as a drive booster for his Big Muff. Gilmour's 2006 On an Island board used two new B.K. Butler hand made Tube Drivers. These were a slightly different version to the original BK Butler/Chandler version. One was set for overdrive, and one was set for a light boost to drive the Big Muffs a bit harder, and for use alone as a light drive pedal as he had done in the 1990s. The Tube Driver settings can be seen in the photo above set for a light drive boost.
There are many other versions of the Tube Driver that have been made, most under the Tube Works, one under the BK Butler/Chandler brand, and an unauthorized knockoff released be Chandler after Butler parted ways with them. There is also a rack mount version. I have played most of them and I suggest staying away from any but the two mentioned above. The three knob version may be found for much less money, but they do not sound the same. I do not recommend the Chandler version without BK Butler's name on it. I have a 2007 model hand made by BK Butler and an original Chandler/BKB version from the 1990s on my board. The 2007 version is 'Real Tube Overdrive' model 911, the same as what David Gilmour used in his 2006 On an Island pedal board. The BK Butler/Chandler Tube Drivers are very similar. There is also a version (from 2007 or 2008) with a bias knob on the back, but I found that feature practically useless for me, making very little difference to the sound. The TD comes stock with a 12AX7 tube. The bias knob allows you to reduce the gain, similar to what would be accomplished by changing to a lower gain tube like the 12AU7. I found it more effective to simply change the tube. A 12AU7 tube is lower gain can remove some of the sharpness from the tone at low drive settings.
Shown above (left to right) - The modern hand made BK Butler Tube Driver, the "Pulse" era BK Butler Tube Driver distributed by Chandler, the unauthorizrd Chandler knockoff, and the three knob Tube Works version
SOUND CLIPS - With just a light drive setting the TD works great with a neck pickup for solos and blues playing. It is perfect for songs like Shine on You Crazy Diamond and Coming Back to Life. The sound holds its own against a Big Muff when cranked into full overdrive. Here are clips of the Tube Drive played with a EMG equipped Stratocaster through a Fender Twin Reverb and a Reeves Custom 50 (Hiwatt Custom 50 replica).
BKB/Chandler Tube Driver - Light drive/boost demo. TC Nova delay. 12AU7 tube.
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Clips below are played with a 2008 American Standard Strat, Seymour Duncan SSL-5 bridge pickup, Fender CS69 neck pickup, or Seymour Duncan SSL-5 bridge pickup, into a '65 Fender Twin Reverb RI or a Reeves Custom 50.
LIGHT DRIVE / BOOST SETTING - Example of the Tube Driver light drive setting with a Fender Strat into a Reeves custom 50. Settings shown above.
MP3 Sound Clip - Tube Driver light boost setting, Boss CE-5, and Nova delay. 12AX7 tube.
BOOSTING A BIG MUFF WITH A TUBE DRIVER - A Tube Driver can be used as a light boost before or after a Big Muff in the signal chain. Muffs like to be driven hard and like a loud, clean tube amp to sound good, but sometimes that is not enough for lead or solos, especially with modern Muffs. Driving a Muff with a driver can make the Muff tone come alive, smooth out the tone while adding some gain and mids, and help it cut through in a band mix better. Most modern Muffs and some vintage Muffs can really benefit from this type of boost. The Big Muff sound is slightly warmer when placing before a Tube Driver, and slightly sharper when placing it after. The tone of a Tube Driver is fairly transparent when using as a boost, but you can also lightly color the Muff tone when boosting.
BIG MUFF BOOST (settings shown above)
Tube Driver set for boost AFTER a Civil War Big Muff - smooth tone
MP3 Sound Clip - Boss CS-2 Compressor > Tube Driver > Big Muff
Tube Driver set for boost BEFORE a Civil War Big Muff - grittier tone
MP3 Sound Clip - Boss CS-2 Compressor > Big Muff >Tube Driver
HOW TO BOOST -What the boost does really depends on the settings of the booster and the Muff and where the booster is placed in the chain, before or after the Muff. Putting most drivers after the Muff seems to be a bit smoother, and before the Muff usually has more crunch and attack. You can get harsh top end, smooth top end, boomy lows, light lows, or whatever you want if the booster has a tone control, or better, a bass and treble control. Also which one is "driving" which has an effect on the tone - meaning which has the high gain and which the low. The Muff sustain can be set high and the drive on the booster pedal low, or vise versa. Each yields a slightly different tone. Set the booster pedal's bass and treble or tone knob to be as transparent as possible, in that the clean tone is not colored when the booster is switched on. I suggest starting with the booster placed after the Big Muff. Set the Big Muff sustain and booster drive both at 50%. Then adjust the Muff sustain up, booster drive down until you get the tone you want. You may also want to try it the other way around, with the drive pedal having the high gain and the Muff low gain. If the sound craps out and sounds farty, or drops out when playing the low E string, there is too much gain from one pedal or the other casuing the signal to overload and break up. Experiment with the gain/drive of each pedal until you have a sound that is almost to the point of breaking up. If you can't find a suitable sound with the booster placed after the Big Muff, try the procedure again with the boost in front of the Muff. Keep in mind, some vintage and boutique Big Muffs sound so good at high gain that you may not see much improvement by boosting.
Here is my favorite setup:
Tube Driver - Placed before the Muff in signal chain. Hi EQ at 4, lo EQ at 6, drive at approximately 1 to 1.5
Muff sustain at about 65-70%, tone about 35%, or whatever tone setting works on your rig in the Gilmour range.
CAN A TUBE DRIVER HANDLE LEADS LIKE A BIG MUFF? - It can, and Gilmour has been using the Tube Driver as his main distortion since the 2006 On an Island tour finished (according to him). Set for overdrive with some compression or EQ, it does a great lead tone, though it does not have that huge bottom end and scooped mid tone you find in a Big Muff. I was going for the DSOT/Pulse live tone here. A Civil War Big Muff was used for the song Sorrow, so I'm using the Tube Driver here to compare to a Muff. Strat into a Fender Twin Reverb.
WHAT TUBES TO USE - Preamps tubes can easily last 15 years or more with moderate use and 10 years or more with very heavy use. Chances are you will never have to replace it, but you may want to experiment with different tubes to see which sounds best in the TD. The stock tube that shipped with my 2007 TD was unmarked so I am not certain what brand it was, but Butler said it was a pre-war Yugo 12AX7. It was a bit too much distortion for the low drive settings, so I swapped tubes. Lower gain should give a smoother sounding overdrive, but that's not always the case with different tube brands. It is worth noting that certain NOS (new old stock) tubes sound much better than modern tubes. Very few factories make vacuum tubes the way they used to be made. I suggest staying away from cheap, noisy tubes, such as the Groove Tube brand. The best modern tubes seem to be the ones made by JJ Electonics. I use an old GE 12AU7 in my BKB/Chandler Tube Driver, and JJ Electronics ECC83/12AX7 in my 2007 BKB Tube Drivers. I tried 12AT7s in the newer TDs and did not hear a big difference vs the 12AX7, but it was a bit smoother. Below are the tube gain factors.
Approximate Gain Factors
100 = 12AX7, ECC83, 7025, ECC803, E83CC, 6681
70 = 5751
60 = 12AT7, ECC81, 6201, 6679, 4024
45 = 12AY7, 6072
41 = 12AV7, 5965
19 = 12AU7, ECC82, 5963, 5814, 6189
OP-AMP MODS - You may notice that the op-amp on the circuit board is mounted in a socket, so you can swap out other higher quality op-amps to see if you like the sound better. The op-amp is the small back box with 8 pins on the left hand side of the circuit in the pix below. I tried a JRC4558D, and another that I think was an OP275. The swaps did not improve the pedal to my ears, but I have heard other peaple say they had good results using Burr Brown op-amps, specifically the OPA2134.
OLD BK BUTLER/CHANDLER TUBE DRIVER VS NEW 2007 BK BUTLER TUBE DRIVER - Do they sound any different? Not much, but there is a difference, and the circuit is not exactly the same. There is a tad bit more drive/gain on the older TD when set to 10 than the newer TD. The newer TD has drive/gain all the way from 1-10, whereas the older one has no drive until you get to about 2. The bass and treble knobs also need to be set slightly different to get the same tone on each pedal. Below are a few comparison clips. These comparison clips are not the correct overdrive settings for Shine On You Crazy Diamond, just what I had set at the time I banged them out. The drive is set around 85%. Both TDs use the same GE brand 12AX7 tube. Strat into a fender Tewin Reverb.
MP3 Sound Clip - BK Butler/Chandler Tube Driver from 1990s
MP3 Sound Clip - BKB Butler Tube Driver made in 2007
Shown Above (left to right) - A "Pulse" era BKB/Chandler Tube Driver circuit, and the later 2007 BKB Tube Driver circuit with bias knob
WERE DAVID GILMOURS TUBE DRIVERS MODDED BY PETE CORNISH? - If you count adding an input and output buffer on the front and back end, then yes. Pete added his tube buffers to all of the pedal circuits included in David's Mark 2 pedal board used for the On an Island tour in 2006. Pete has stated the Tube Driver circuits themselves were stock, but there is one resistor (R2) disconnected from David's Tube Drivers, as you can see in the photos of David's 2006 pedal board being constructed below. This is a 1m ohm pull down resistor that appears to set the input impedance, so if a pedal with a buffer or any type of booster circuit is placed before the TD, it alters the signal impedance, causing the TD to sound a bit more harsh and gainy than normal. You can test this by playing the TD straight into your amp with no other pedals, then comparing that to sound of the TD in your pedal board chain. If you hear a big differance, you may want to clip this resistor off the circuit board. My TD definitley lost the smooth sound at low gain setting when I used it on my pedal board with Boss buffered pedals, so I removed this resistor and hear a minor, but noticeable improvement. There is also a blue 470 ohm resistor at R18 in the power decoupling section that may have been changed by Pete Cornish, likely to work with the input and output tube buffers he built into David's MKII pedal board, though I cannot tell the value of the resistor it was replaced with from the photos. I also have one BKB TD with a blue resistor here, so there may have been no change to Gilmour's circuit.
Shown Above (left to right) - BKB Tube Drivers from David Gilmour's 2006 pedal board, and the stock BKB Tube Driver circuit from 2007.
If you want to read more about BK Butler and the Tube Driver, there is a good interview over on the Tone from Heaven website.
NOTE - I have listed the gear and settings I use in most cases, for reference, but note that the tones may not exactly match your rig, depending on which amp you use, your guitar, and pickups, and fingers :) I am not a Gilmour/Pink Floyd gear expert, so your results may vary.
Review written in 2007. Updated in 2010, 2011