Chandler Tube Driver Bias Mod

Oct 02, 2009 by sssteeve » 09 Dec 2011, 09:55. I was wondering if anyone has a schematic for the Chandler rack mount TDR-101 Tube Driver. It is quite different from the original 4 knob pedal- which I bought in 1986/7 but traded in a year later for the rackmount version. (I should have gotten suspicious when the store was offering me the full price I had. I went right out an bought a rack mount Chandler tube driver even though I was a poor college student at the time. I still have it, and used it for many years with a Carvin 100 watt amp to get a great sound at lower volume levels. Eric Johnson still uses a similar tube driver for his lead tone. Chandler's out of business now I think. Chandler Tube Driver Bias Mod. 2021.07.24 16:55. God%27s Eye Software Download For Android. Signal Chain - Paul Reed Smith Custom 22 Brazilian Ltd - Chandler Tube Driver - Orange Dual Terror - Mesa 4x12 Rectifier Slant - AKG C414 XLii - API 512c - A. (left to right) A Tube Works 901 Real Tube pedal from 1987, a Dean Markley Overlord from 1988 (Real Tube knockoff), and a 1986-87 B.K. Butler/Chandler Tube Driver PULSE TUBE DRIVERS - David used two original 1986-87 BK Butler/Chandler branded Tube Drivers in his 1994 Division Bell live rig.

David Gilmour has been an avid Tube Driver user since around 1993. He first used them in the recording sessions for Pink Floy's The Division Bell album. Those same sessions also resulted in the Division Bell companion album, Pink Floyd's The Endless River, which was not completed until 2015. He used Tube Drivers extensively for his 2006 album On an Island and the subsequent tour, heard on the Remember That Night and Live in Gdansk concert releases, as well as his 2015 Rattle that Lock album and tour, and his 2017 album, Live at Pompeii. His collection of Tube Drivers includes several 1980s originals, several 911 Tube Drivers, a gold Tube Works 911 Tube Driver, and the five knob Real Tube version from Tube Works.

'David started using a Tube Driver during recording for the Division Bell album in 1993 and has used them ever since. It is his main go to distortion. We have tried all the variants - Chandler ones with in line PSU, 3 Knob version, rack mount, etc but the only one he likes are the original mains powered 4 knob with 'designed by BK Butler' on the top. He does not use any with the bias control fitted.' - Phil Taylor, Guitar tech for David Gilmour - June 2018 issue of Tonequest

'The overdrive I tend to use is a (BK Butler) Tube Driver these days, often with a compressor feeding into it. On this one (Rattle That Lock), it’s actually pretty much untreated.' - David Gilmour from Guitarist Magazine 2015

For the Gilmour sound, I think the Tube Driver sounds best with a Hiwatt Custom 50 (DR504), Custom 100 (DR103), Fender Bassman, or Fender Bandmaster. Those were the magical combinations heard in Gilmour's work from 1990 and onward. For that Pulse or On an Island era light drive and heavy overdrive tone through a Hiwatt or Fender amp, this is your pedal. You can hear it 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, Remember that Night, and Live in Gdansk. It was the primary overdrive and distortion pedal for David's On an Island tour. He even uses it to mimic the sound of the Selmer Bass & Treble amps that Syd Barrett and he used in the early Pink Floyd. David had previously used other boosters, such as the Colorsound Power Boost, Pete Cornish ST-2 Booster (a modified Power Boost), or Mesa Boogie head (used as an overdrive in his signal chain) in the 1980s. Once he switched to the TD it remained his primary overdrive pedal. You can read more about the Butler Tube Driver HERE. A list of the different versions of the Tube Driver can be found HERE.

Here are a few examples I recorded of the Gilmour Tube Driver sound.

Time Solo - Strat into a 911 Tube Driver > Future Factory delay > Reeves Custom 50

Take A Breath solo - Demeter Compulator > Tube Works 911 Tube Driver > Future Factory Delay > Ambi Space Plate Reverb > Reeves Custom 50. Strat with SD SSL5 pickup.

Castellorizon - BKB 911 Tube Driver > TC Nova delay into a Reeves Custom 50. Stratocaster with EMG pickups.

In Any Tongue solo - Tube Works 911 Tube Driver > Future Factory Delay > Ambi Space Plate Reverb > Reeves Custom 50

Pigs Outro solo - Tube Works 911 Tube Driver with > Future Factory Delay > Ambi Space Plate Reverb > Reeves Custom 50

Calling Part 2 (guitars)- 1980s BKB/Chandler Tube Driver > Boss CE-2 Chorus > TC Nova delay into Fender Bassman. Stratocaster with EMG pickups and E-bow.

5 A.M. - Boss CS-2 compressor > 1980s BKB/Chandler Tube Driver > TC Nova delay into a Reeves Custom 50. Les Paul with P-90 pickups and Bigsby tremolo.

Louder Than Words solo - Boss CS-2 Compressor > BKB/Chandler Tube Driver 12AX7 tube > Future Factory Delay > Ambi Space Plate Reverb > Reeves Custom 50

Coming Back to Life solos - Boss CS-2 compressor >1980s BKB/Chandler Tube Driver > Boss CE-2 chorus > TC Nova delay. First solo with EMG-SA neck+middle pickup. Second with neck pickup.

DIVISION BELL and THE ENDLESS RIVER - For Pink Floyd's 1993 recording sessions for the Division Bell and The Endless River albums, David used several versions of the Tube Driver, shown above. The pedal on the left is the Dean Markley Overlord (a knockoff of the Real Tube). It is barely visible, but there is a power switch on the back and Dean Markley script above it. To the right of that is a 1980s Tube Works 901 Real Tube. On the far right are two1986-87 period BKB/Chandler Tube Drivers. It is unknown which of these were actually used on for the album tracks, but David used 1986-87 Tube Drivers in his Division Bell tour rig 1994.

Tube Drivers from Pink Floyd's 1993 Division Bell sessions - (left to right) Dean Markley Overlord, Tube Works Real Tube, two B.K. Butler/Chandler Tube Drivers

(left to right) A Tube Works 901 Real Tube pedal from 1987, a Dean Markley Overlord from 1988 (Real Tube knockoff), and a 1986-87 B.K. Butler/Chandler Tube Driver

PULSE TUBE DRIVERS - David used two original 1986-87 BK Butler/Chandler branded Tube Drivers in his 1994 Division Bell live rig. These have become known as the 'Pulse' Tube Drivers, as that is the name of Pink Floyd's popular live concert video and album from the 1994 tour. The red knobbed one was labeled #1 and the other #2. Both had identical settings on the first leg of the tour. During the final 14 concerts at Earls Court in 1994 (heard on the Pulse album and video), David set the DRIVE and LO higher on his #2 Tube Driver. A common mistake people make is to set their modern 911 Tube Driver to David's exact Pulse settings and expect it to sound like his did, but 911 Tube Drivers do not have the same pots or circuit as the older Tube Drivers. In fact, each Tube Driver version requires different settings to sound the same, and even the 1986-87 Tube Drivers could sound different from each other.

David Gilmour's 1994 Pink Floyd pedal board with two 1986-87 BKB/Chandler Tube Drivers labeled #1 and #2. These settings were used prior to the Earls Court concerts, released as the Pulse live album and video, so may not represent what was heard in those recordings.

I suspect the circuits in both of David's were the more common second version from 1987, but there is no way to know for sure. You can read more about these Tube Drivers HERE. A list of the different versions of the Tube Driver can be found HERE.

Gilmour's #1 and #2 BKB/Chandler Tube Driver settings from the 1994 Pink Floyd tour (left) and what those same settings would be on a BK Butler 2006 911 Tube Driver (right). This is assuming that the circuits inside each of those 1986-87 Tube Drivers used in 1994 were the more common second variant with the green backed pcb. They may not have been.

Gilmour revised his #2 Tube Driver settings for the October Earls Court concerts, shown above. These are likely the overdrive settings heard on the Pulse album and concert video. The #2 Tube Driver was used for almost all of the overdrive rhythm guitar and overdrive solos heard in songs like Shine On..., Astronomy Domine, Learning to Fly, On the Turning Away, Another brick in The Wall II, Time, and Coming Back to Life.

These are David's revised #2 Tube Driver settings (left), and what they would be on a 2006 model 911 Tube Driver (right). This overdrive tone is most likely what was heard on the Pulse concert album and video recording from the final Earls Court concerts. Again, this is assuming that the circuits inside each of those 1986-87 Tube Drivers used in 1994 were the more common variant with the green backed pcb.

Chandler Tube Driver Manual

The Sovtek Big Muff was David's primary distortion pedal in 1994, and according to his signal chain, the #1 Tube Driver was placed before the Muff and the #2 was after it. Each of those placements affects the the Big Muff sound differently. According to the the signal router visible in David's rack during the concerts (LEDs indicated which effects were on for any given song) David almost always ran the #1 Tube Driver into the Big Muff or Rat for his high gain solos, but for the Time solo played in the European leg of the tour, he sometimes ran the Big Muff into the #2 Tube Driver which followed it. The #2 was also used for most of the overdrive tones, sometimes combined with a Boss CS-2 or Cornish SS-2. Did these duplicate Tube Drivers with identical settings sound the same? One possibly had a lower gain or different sounding preamp tube inside than the other, or each may have had different guts inside, as there were four slightly different circuits used in those 1980s Tube Drivers.

Chandler tube driver bias mod list

'David doesn't necessarily use anything exactly as it is, or as you would expect. There are times when he has run a Big Muff into various things such as a Boogie head or a BK Butler Tube Driver...'- Phil Taylor, 2009 Guitar Player

ON AN ISLAND TOUR, REMEMBER THAT NIGHT, and LIVE IN GDANSK - Gilmour's 2006 On an Island Toureffects board used two new model 911 B.K. Butler Tube Drivers, made in 2005. Both were placed after the Big Muffs in the signal chain. These were a reissue of the Tube Works model 911 Tube Driver from the 1990s, not the 1980s Tube Drivers. The 911 had a slightly different circuit than the 1980s BK Butler/Chandler Tube Drivers David used in '94, as well as different pots. One TD was set for high gain overdrive, and the other was set for a light drive to blend with the Big Muffs (P-1 and G-2), and for use alone. These were David's primary overdrive and distortion pedals for the tour, and I would estimate 75% of the guitar solos heard on that tour were played with one of these Tube Drivers. You can read more about the Tube Drivers in this rig HERE

I don’t use the Big Muff or the Fuzz Face as much anymore. I currently have two BK Butler Tube Drivers on my pedalboard, and I just use one or the other. If I need a little something more, I’ll stomp a compressor with a bit of drive onto the beginning of it, and that will turn things up another whole gear - David Gilmour

'He has always had two (Tube Drivers) in his guitar setup, since '94, one set on minimum gain, the other more. During most of the On An Island Tour in 2006 he used the second one instead of using a Big Muff in Comfortably Numb, giving a different character of sound. On the last tour 2015-16 he had three in his setup, each set to a different amount of distortion' - Phil Taylor, Guitar tech for David Gilmour - June 2018 issue of Tonequest

(shown above) David Gilmour's MK2 Pete Cornish effects board settings from his 2006 tour, including two B.K. Butler Tube Drivers made in 2005

RATTLE THAT LOCK TOUR - David brought out the Tube Drivers again for his 2015/16 tour, shown below. This time he used an original 1980s BK Butler/Chandler branded Tube Driver and two more recent B.K. Butler 911 Tube Drivers. Each was set for a slightly different tone and level of drive. David did not use them to boost/blend with his Big Muffs on this tour. They were only used as overdrives, blended with one of his three compressors. It is unkown which circuit was inside the 1980s Tube Driver, as Butler stated shipped David four 911 TD circuits in 2005, requested to replace the circuits in his old Tube Drivers.

(left to right) A 1986-87 BKB/Chandler Tube Driver (#1) and two BK Butler 911 reissue Tube Drivers (# 2 and #3) on David Gilmour's 2015/2016 pedal board. All had been modified with custom power supplies

These are David's Tube Driver #2 settings from his Rattle That Lock tour (left), and what they would be on a 2006 model 911 Tube Driver (right). This is assuming that the circuit inside that 1986-87 Tube Driver is the more common variant with the green backed pcb.

The #1 Tube Driver with the red drive knob was actually used for most of the lower gain tones, despite the fact that the red drive knob shows a high gain setting. There is a sticker visible on top of that TD that appears to say GAIN SWITCH, and what appears to be a switch on the back of the TD. The fact that this TD does not have a high gain sound indicates that it has had some type of modification to reduce the gain, which probably explains why it was given a red knob cap. Pete Cornish added a resistor to one lug of the drive pot of one of the TDs in Gilmour's 2006 Cornish board, so this may be a similar, switchable mod here.

David's 2016 Rattle That Lock tour Tube Drivers shown from the top and rear. Note the 'gain switch' sticker on the TD on the left and what appears to be a switch on the back of the pedal, indicating that it has had some type of gain modification

A 1980s BKB Tube Driver (left) and a Tube Works gold plated 911 Tube Driver from David's gear warehouse

A 1980s BKB Tube Driver (left) and two Tube Works gold plated 911 Tube Drivers used for the Peter Green Celebration concert in 2020

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SELMER AMP TONE WITH A TUBE DRIVER - When David joined Pink Floyd in 1968 and took over vocals and guitar for Syd Barrett he was using the same gear that Syd had been using - a Telecaster, Binson Echoec, and Selmer amplifiers and speaker cabinets. The Selmer had a unique, jangly, overdriven sound that a lot of people confuse with a fuzz pedal. There is no fuzz on Piper at the Gates of Dawn, Syd's first Pink Floyd album. He did own a fuzz pedal - a Colorsound (not a Vox) Tonebender - but he rarely used fuzz. His fuzz use was so rare that there is only one photo of him with one, from May 1967, and the Tonbender input is not even plugged in! If you want to hear what Syd's actual fuzz pedal sounded like, listen to the fuzz solo in the See Emily Play single.

Syd Barrett and David Gilmour playing through Selmer amplifiers in 1967 and 1968

The Selmer Truvoice Treble 'N' Bass Mark II amplifier (left), which had a normal and a bass channel, and Selmer Stereomaster (right)

The core guitar tone on the Piper album was primarily the 50w Selmer Truvoice Treble 'N' Bass Mark II amp. It was a two channel (normal and bass) 50w amp, and the louder you turned it up, the more it distorted. Syd used the normal channel input. When performing live Syd used the Truevioce or a Selmer Stereomaster amplifier with a matching Selmer speaker cabinets. The Steremaster essentially sounded the same as the Truevoice, but it had two 50w amplifiers built in (50w each for stereo, or 100w mono), each with a series of five pre-set EQ buttons that could be used in addition to the treble and bass knobs. David continued to use those Selmers when he joined the Floyd, as he was basically picking up where Syd left off and using his gear. Below is an extraction of Syd playing guitar through his Selmer and Roger Waters playing bass from the Piper at the Gates of Dawn sessions.

Interstellar Overdrive - Isolated Guitar and Bass

1980s BKB Tube Driver (left) and Tube Works Real Tube settings to mimic the Selmer sound

David soon moved on to Hiwatts and began to develop his own sound. As new material without Syd was written, Pink Floyd stopped playing a lot of those early Selmer era Floyd songs. Later in his career David began playing some of those songs again with the Floyd and in his solo concerts. Astronomy Domine was a staple for his concerts beginning in 1994, but he also played Arnold Layne in later shows, and a one-off performance of Remember A Day. To get those Selmer tones David used a Tube Driver into his Hiwatt amps, which got close, but you can actually get even closer to the Selmer than David did by using 1980s era BK Butler/Chandler Tube Drivers. The 5-knob Real Tube version of the TD from Tube Works also works for this sound. You need a bright, jangly amp tone. A Bassman or Hiwatt are perfect for that. I dial the presence control all the way up on my Hiwatt and set my bright channel volume fairly high. I set the TD for a bright overdrive, dial the volume down sightly on my Telecaster, and play right over the bridge pickup to get the sound as bright as possible. My pedal settings are shown above. Note that not all 1980s Tube Drivers sound the same, so I show a range of LO and DRIVE settings that work on the TDs in my collection.

Here are a couple of sloppy clips of the Selmer tone with a TD.

Interstellar Overdrive - Telecaster into a 1980s BKB/Chandler Tube Driver > Future Factory delay > Reeves Custom 50.

Astronomy Domine - Telecaster into a 1980s BKB/Chandler Tube Driver > Future Factory delay > Reeves Custom 50.

There is a hint of fuzz on top of the Selmer tone that is not quite the same with the TD, but in all other respects it sounds very close. You can also get a similar sound with a 1990s era 911 Tube Driver or the 911 TDs Butler has been making since 2006 by dialing the hi and lo knobs to zero. The tone is similar, but not quite as bright and accurate as the 1980s Tube Drivers or Real Tube pedals.

Shown above (left to right) - An original long plate Ei Yugoslavian 12AX7 tube re-branded 'TUBE DRIVER' that shipped with the original BKB/Chandler Tube Driver in 1986-87, and a short plate, unbranded Goldern Dragon 12AX7 that ships with the reissue Tube Drivers made since 2006.

WHAT TUBES DID DAVID GILMOUR USE?- There is much confusion about this. Butler said he shipped four new 911 Tube Drivers to David in November 2005 with NOS Yugoslavia 12AX7/ECC83 tubes (old stock from his Tube Works company), and those could be seen in the Pete Cornish photos of David's 2006 pedal board being built. He also shipped four more 911 Tube Driver circuits (with Yugo tubes) to replace the circuits in David's older Tube Drivers. Pete Cornish has said he did not change the tubes when he built David's 2006 board, but in 2008 he told some people that David used 12AT7s in his Tube Drivers, not 12AX7s. The bottom line is, no one really knows what tubes were used in any of David's various Tube Drivers except Phil Taylor, David's backline tech who takes care of such things, or David himself.

There is no information available about the tubes in David's BK Butler/Chandler Tube Drivers used in his 1994 rig or the Tube Drivers in his 2015/2016 rig.

IMPEDANCE ISSUES - PUT A BUFFER AFTER IT! - There is a signal impedance issue with Tube Drivers and Real Tube pedals that could cause tone problems in your signal chain. The Tube Driver has a buffered, high impedance input, but no output buffer. The passive tone circuit hangs a high impedance signal on the output, so changes in loading and capacitance can result in a loss of bandwidth, usually high frequencies, altering the tone in a negative way. Your guitar's output impedance is higher at high frequencies and lower at low frequencies, and varies as you play. Since the highs have a higher impedance, you will lose high frequencies if the input impedance of the circuit following the guitar is too low. That same priciple typically applies for each circuit in your signal chain after the guitar as well. That is why you always want a low impedance output from one pedal going into a high impedance input on the next pedal. A good rule of thumb for a well balanced pedal board signal chain is to have the input impedance of each pedal be about 10x larger than the output impedance of the pedal before it.

With moderate drive and treble settings, like Gilmour's low gain TD settings, the TD's output impedance should be around 10KΩ. That's a bit high, but OK if you are just boosting it into a Big Muf, which has an input of 120-130KΩ, or a Boss CE-2 chorus, which has an input of 407KΩ. The output impedance of the TD changes depending on the knob settings though. With high drive, treble, and volume settings, like Gilmour's high gain TD settings, the output can be as high as 90kΩ. In that case a 1MΩ input on the pedal following the TD is a good idea. You can accomplish this by placing a pedal with an always-on 1MΩ buffer, like most modern Boss pedals, immediately after the TD. Or you can place a 1MΩ buffer after the TD, like a Cornish LD-1. Empress, JHS, Fender, and Mesa/Boogie all offered buffer pedals at the time I wrote this article. You can also place the TD in a loop that has a buffer on the output of at least 1MΩ.

The Tube Drivers in David's pedal baords always have a buffer after them to prevent those tone loss issues.

WERE DAVID GILMOUR'S TUBE DRIVERS MODDED BY PETE CORNISH?- If you count adding signal buffers and changing the power supplies, then yes. Pete added his tube buffers to the Tube Drivers used in David's 1994 concert rig and his buffer/line driver at the output of the two TDs in David's Mark 2 pedal board used for the On an Island tour in 2006.

The TD already includes an input buffer, but no output buffer. It has a high impedance output, so it is prone to volume and tone changes if it does not see a buffer before going into additional effects. Pete's line driver made the TDs unity gain balanced with the rest of the pedal board. The power transformers inside each TD was also removed and a new 3 stage power supply installed which separately powered the op-amp, tube, and tube heater. A separate supply powered the line drivers.

BK Butler said the units he sold to David were stock and Pete Cornish has stated the actual TD tone circuits inside were not modified by him, but there is an extra resistor added to the 3rd lug of the drive pot in one TD in the Cornish 2006 pedal board that was not added by Butler.There is also one resistor (R2) that appeared to be disconnected in the photos of David's 2006 pedal board being constructed, shown below. The resistor is actually there, just mounted vertically. This 1m ohm pull down resistor is a DC reference resistor that sets the input impedance and is needed to prevent unstable DC level after C1.Test playing the TD straight into your amp with no other pedals, then compare that to sound of the TD in your pedal board chain. If you hear a big differance, you may want to add a larger resistor here (per Mr Butler's advice). Butler suggests a larger 2.2M or 3.3M resistor because the higher the resistor value, the less potential effect it should have on your sound. I found it more effective to run my TDs in a bypass loop with with a buffered pedal immediately after in the signal chain, as in the Cornish boards.

Shown Above (left to right) - BKB Tube Drivers from David Gilmour's 2006 pedal board, and the stock BKB Tube Driver circuit from 2007.

HOW TO BOOST A BIG MUFF WITH A TUBE DRIVER - 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 causing 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 are instructions to set up the Big Muff/Tube Driver combo heard on David's 2006 solo tour, as captured on the Remember That Night DVD and Live in Gdansk. Note that these settings are for a Strat with single coil pickups. David used a Pete Cornish P-1, which is a very good Ram's Head era Big Muff clone. David's settings make make the Big Muff right on the edge of choking. If you have a current BKB Tube Driver made since 2006 you will notice when you turn the knobs that you can feel the notches.

1. Set to both Big Muff and TD pedals to David's OAI settings (they are posted here), with the TD following the Big Muff (Cornish P-1). Set the TD drive exactly three notches from zero (the ones you feel, not the notches printed on the pedal).
2. Turn the Big Muff on using your preferred settings, guitar volume at 10, and listen. That's your unity volume.
3. Keep the Big Muff on and switch your TD on. If the unity volume goes down, adjust your TD volume until there is no difference in volume with the TD on or off. Some people may like the volume to boost a bit when they hit the TD, but for now keep them the same.
4. The Big Muff should be right on the edge of breakup. Turn the TD drive pot down one notch and listen for your unity to drop. If it does not drop, turn the drive down another notch. Whatever notch position brings the unity down, you want to be one notch above that. That should give you the exact gain saturation that David had for the OAI tour. One notch too low and the unity drops, one notch too to high and there will be a slight volume boost and too much breakup, but there SHOULD be some breakup. It is literally that fine of a line with the current BKB TD. You just want to determine what level of breakup you can handle. You don't want the low strings crapping out and choking on you, but they should choke a bit. This setup works for The Wall Big Muff tones too.

Chandler Tube Driver Rack Mount

If it breaks up too much for you, back the Big Muff sustain down a hair, and bring the tone up the same amount (they are interactive). Find the balance you like that way, but if you can't handle that Big Muff breakup, then don't boost. This is not a tone that is handed to you, you have to work it out with your fingers, but that is the setup. Note that the instructions above don't work for a 1990's era BKB/Chandler Tube Driver since the volume and tone post positions don't match the later version, so more tweaking is required.

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.

ALTERNATIVES TO THE TUBE DRIVER SOUND - The best alternative to the popular 4 knob Tube Driver is actually the 5 knob Real Tube pedal, model 901, made by Tube Works and designed by BK Butler. The circuit is a bit more complex, but bascially the same design as the 911 Tube Driver only with a mid range knob added. The 901 model can usually be found for much less than the old BKB/Chandler or 911 Tube Drivers. With a similar tube, they can sound exactly the same as the 911 version. They are also in a smaller enclosure and have a wider range of sound due to the added mid range knob, and so can be tweaked to sound good with a wider range of amps. They can be made to sound like anythng from a Tube Screamer to the Mesa Boogie mark series overdrive sound. As with the 4 knob versions, if you want a smoother low gain sound out of the Real Tube, try changing the stock 12AX7 tube a lower gain tube like a 12AU7 or 12AT7. When I set my Real Tube to sound the same as my 1980s or 2007 Tube Driver, I can barely hear any difference in a blind sound comparison.

Tube Works Real Tube and US made Ibanez Tube King. Both are modified Tube Driver circuits

What if you just can't get along with any of the Tube Driver/Real Tube circuits because of the signal impedance issues in your pedal board, or have issues with the internal transformer making hum noise? Another alternative is BK Butler's 1990s era Ibanez Tube King (TK999US), which is a variation on his Real Tube/Tube Driver circuits, only with NO internal transformer. It runs on a standard 9v power supply. At low drive settings the tone is slightly different than a Tube Driver due to the active tone circuit, but it is still closer than most other overdrive pedals. Unlike the Tube Driver and Real Tube, it has a buffered output and becasue the internal transformer was eliminated, it has no loading issues or transformer noise issues.

The classic Boss Blues Driver

There are several alternative, non-tube pedals that can do very similar overdrive tones as well. Nothing out there that I have tried exactly matches the sound characteristics of Tube Driver circuit with a real tube, but the stock Boss Blues Driver is one of the closest. At high gain, the tone is amazingly similar to the sound of the wide open 911 Tube Driver when combined with a compressor like a Boss CS-2. It also matches the low to medium gain Tube Driver tones very well. I think it sounds fantastic through a Hiwatt. Some find it has a bit harsh top end sound through certain amps. The tone range is also slightly limited due to the single tone knob, making it harder to dial in a matching Tube Driver tones on some amps.

Chandler Tube Driver Bias Mod List

Electro Harmonix Hot Tubes and Hot Wax pedals. On the right are my settings to replicate the high gain 911 Tube Driver sound

Another pedal that is very close to the Tube Driver sound is the Electro-Harmonix Hot Tubes overdrive. It is also a good substitute for David's 1970s Power Boost tones. The EHX Hot Wax is an even better alternative that is very versatile in creating all of David's various Tube Driver tones, including the high gain 911 Tube Driver tones. It is a combination overdrive that includes the Hot Tubes circuit and the EHX Crayon overdrive circuit. With both circuits engaged you can recreate David's 2006 tour 911 Tube Driver tones heard on Remember That Night and Live in Gdansk. It also has much more tonal flexibility than the Blues Driver. Here are some comparison sound clips of the high gian Tube Driver sound, like on Gilmour's 2006 tour, Remember That Night, and Live in Gdansk.

Take A Breath solo with 911 Tube Driver - Demeter Compulator Comrpessor, Future Factory delay, Ambi Space plate reverb

Take A Breath solo Boss BD-2 Blues Driver - Boss CS-2 compressor, Boss CE2-B chorus (mix at 30%), Future Factory delay, Ambi Space plate reverb

Take A Breath solo with EHX Hot Wax - Boss CS-2, Future Factory delay, Ambi Space plate reverb

Take A Breath solo with Buffalo TD-X - Boss CS-2 compressor, Future Factory delay, Ambi Space plate reverb

Skreddy Lunar Module Deluxe and Buffalo TD-X. TD-X settings shown are for high gain 911 Tube Driver sound

Chandler Tube Driver Clone

The Buffalo FX TD-X and Skreddy Lunar Module are two other very good alternatives with much more tonal flexibility than the Blues Driver. Both do a good job with the low to medium gain overdrive, and are very smooth, but neither does a better job than the Boss Blues Driver or EHX Hot Wax for the high gain 911 Tube Driver sound. I did find that with EMG pickups the TD-X gets closer to the high gain TD sound than when using single coil, passive pickups, as demonstrated below.

Castellorizon - Buffalo TD-X demo. Strat with EMG-SA pickups and TC Nova delay into a Reeves Custom 50.

Castellorizon - BKB 911 Tube Driver with 12AX7 tube. Strat with single coil pickups (Seymour Duncan SSL-5 bridge and Fender Fat '50s neck pickup) and TC Nova delay into a Reeves Custom 50.

Chandler Tube Driver Bias Module

The MXR Fet Driver is a part-for-part replica of a 1980s Tube Driver that uses uses a charge pump to get the +/-15 volts needed, and the tube stage was replaced with FETs (field effect transistors). The MXR does the high gain TD overdrive OK, but I could not get the low gain overdrive tones to exactly match a Tube Driver. Very close though, but missing something. The MXR has slightly less mid range than the TD, so that could be the difference I hear. The tube in the TD colors the distortion from the op-amp. That may be an effect the FETs in the Fet Driver cannot sucessfully replicate .

The Hermidia Audio Dover Drive was supposed to be close to the Tube Driver sound, and it is a good overdrive, but I don't think it sounds anoy closer to the TD as the pedals listed above.

You can read more about the Tube Driver HERE.

A list of the different versions of the Tube Driver can be found HERE.