Secrets Revealed!!-What's Inside This BK Butler Tube Driver Real Tube Overdrive 

mrmongo673 me too Mr Mongo, me too!

Have a listen here ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE--LieE9JKqxo.html

Which means you've been supplying the tube with 24Vdc instead of 12Vdc,though it may sound slightly better,the op-amps are more than likely running of off too high a dc supply,possibly near the limit they can handle.

I also have a older 3 knob Tube driver that has been modded with a bias knob by Fromel. I'm running a 12au7 tube and at 18v on my board. It's not a clean sound but it's cleaned up a bit over a 12x.

Because this is a starved voltage tube pedal built to make as much profit as can be made for as little outlay as possible,starved tubes are just a gimmick,the same or better can be done for pennies with solid state.

Replacing the internal transformer with an external brick would be tricky and probably more of a pain that just replacing the existing transformer. The stock transformer supplies both the tube filament voltage and the audio circuit voltage. Converting to external supply would require a substantial bit of rewiring. Butler is still making these, so I would recommend contacting him to see if they have replacements or are willing to do the conversion for you.

@@LawrencePetross Thank you for the feedback and info.

It should be and their support should have sent along documentation for the install. if they did not, I would contact them directly.

This guy was working with a knock off, the bias control model is one of the real BK units

@@conservativestrawman9837 This is not a knock off, it is one of the earlier units built by Butler but distributed by Chandler. Also not every real one with a bias control. From the Kitrae site: TUBE DRIVER VERSIONS - There have been numerous version of the Tube Driver made since the 1980s, but these are all of the 4 knob versions. A mostly complete list of all the other versions can be found HERE. •1985 - B.K. Butler/Chandler Tube Driver. Marked TUBE DRIVER™ and CHANDLER INDUSTRIES-PATENT PEND. on the front. •1986-87 - B.K. Butler/Chandler Tube Driver. Marked TUBE DRIVER®, Concept & Design: B.K. Butler and CHANDLER INDUSTRIES, INC on the front. •1988 - Chandler Tube Driver. Knockoff made by Chandler after Butler parted ways with them. Only marked with script Chandler logo on the front, no BK Butler. •1993-94 - 911 Tube Driver - Made by Butler's Tube Works company. A four knob version of the Tube Works 901 Real Tube pedal, which was an improved Tube Driver. •2005 - 911 Tube Driver. A reissue of the 1990s Tube Works Tube Driver.

Nice it’s been 3 years , you tried them yet, I have the effectrode tube drive which is real easy to swap tubes on, trying to work out whether I really need one of these or should just buying a selection of vintage tubes, so if you can recommended any 12ax7s I’d appreciate it eBay is a minefield for valve shopping!

Ryan Foarde the power supply is +15, -15 volts DC. The tube supply voltage is 30 volts DC.

Find all engineering info in the RCA Tube Manual #21. I still have mine from 1967.

@@TheTubeDudeThats a gem! Also came here wondering why the plate V wasn’t in the hundreds, found the characteristic graphs pretty quickly. Gotta love the intro paragraph as well!

Alex Sternwart hello! These used a step down transformer that took line voltage down to +-15 volts DC. It would require a complete redesign of the power section of the pedal. As well you still have to find room for the tube. The second version (in the blue vase I believe) did this as you suggest worth an external power supply but there are folks who say they don’t sound the same as the originals with the on board transformer.

@@LawrencePetross Thank you for the fast answer! My suggest was that inside is some free space and would become a bit more if i would take away the transformer. The target would be the size of a strymon riverside for example. There re some power supplies they can switch from 9/12/18.Would that help to avoid the complete reconstruction of the curcuit?

@@alexsternwart7057 The 1st Butler Tube Drivers were 3 knob 9v battery powered. Batteries didn't last long, so most use a Boss style 9v per supply. I have 1 of those that has been modded with a bias knob. It's on my board, not the big 1 with it's own pwr cord. This thing is GREAT. And only for $165.

Pretty straightforward. Just exchange a pot for the fixed resistor. For value is go with twice the fixed resistor value so you can have some boost as well as cut (technically since the stack is passive it’s just less cut, but that’s not usually how we hear it). For adding an output buffer, I’d recommend grafting in the transistor buffer from the TS-9 or equivalent. Just a few parts and it’ll drive plenty. Adding the output buffer may change the tone and feel though as you are altering the loading of the circuit.

You read my mind... a year ago! :-) I wonder if a sweep-able mid would be doable.

High Rick, A well design printed circuit board is just as capable of delivering the sound quality level of point to point. After all, copper is copper. If you maintain the same basic standards as you would with point to point, there is not going to be any measurable difference between the two. I do agree, point to point is much easier to repair when the need arises. Now you mentioned solid state and that is a different kettle of fish from pcb vs point to point and better left for a different discussion. Thanks for the question!

Hello Rick, The BK Tube Driver circuit is hardly PTP but instead laid out on a printed circuit board (PCB). That being said PTP is more robust and durable over time where high voltage and heat are concerned. However. the BK Tube Driver circuit after the transformer contains neither. I'd say the tone and reliability on the BK using the PCB speaks for itself considering this classic pedal has played a central role in the tones of David Gilmour, Eric Johnson, including countless others and would not benefit from PTP in any way.

this pedal is not PTP the whole audio circuit is on the PCB. This is basically a cheap opamp slamming a low voltage starved tube circuit, and it is fuzzy and undynamic compared to real high voltage run tubes. I dont care who famous played it in the 80s or whatever, I played it and think it sucks

Robert Joshlin The circuit as manufactured by Chandler is done on a pcb. The circuit as hand manufactured by B.K. Butler is done on a point to point.

True PTP does not even need a board,though only for structural strength as far as component leads go,tag strips,eylets,turrets,pcb,all can be bad all can be good,design and layout make or break the deal.I used to use turret pins when building tube amps,the pins can act as ariels picking up static voltage fields,low profile is generally best,but layout again is one of the biggest deciding factors,especially in high voltage realms,thought this pedal shown here is voltage starved and not exactly going to be much of a problem,other than EMF coupling into the tubes metallic parts.

Brian M hey that's what this is all about right, sharing info for better understanding. The tube requires 2 voltages, one for the heating element and one for the amplifying elements. Tubes are happiest with higher voltages, the 12AX7 likes 150-300 volts on its plates to sound like we expect tubes to sound. In the Tube Driver, the tube has about 30 volts on its plates. This is known as "starved plate mode". In this mode the tube overdrives and distorts the signal much easier and in a very different way from its high voltage mode. Not better or worse, just different. Yes, some pedals use JFETs for the amplification and clipping devices. The can be used like the tubes are used and in many different ways as well. Generally, JFETs are happiest running at much lower voltages than tube, 5-30 volts, which is why you see them so often in pedal circuits. In the Tube Driver the tone stack is after the distortion. It is filtering in much the same way as an amplifier tone stack would. Yes the filtering, before, between and after the clipping, is what gives an overdrive/distortion a majority of it's character. The way the signal is clipped gives it the rest. This is why you see so many different dirt boxes. Even minor changes can have a major impact in tone and feel.

Thanks for the break down Lawrence! Much appreciated!!! So cool that you do this, my nerd side loves it!

I don't agree with you. Maybe yours but I have the new 5 knob sitting on the shelf and it's quiet enough. Also have an older 3 knob modded Tube Driver on my board. It's mod is the bias knob, done by Frommel, very clean. I'm using an old RCA 12AX7 with a metal tube cover on it. For "more power" also running on 18v pwr. Great sound,tone, and size. Stacks nice with a Meat and 3 modded Soul Food and a Alchemy modded Blues driver. 3 drives on my board means none are really heavy gain for most part

@@sparkyguitar0058 I had a few techs who got the same one - and they noticed a difference... even found someone online here on RU-vid noted the same... Frankly I don't know why

@@RobertLongM Wow That's new news to me. I've opened my up and really doesn't look much different than my modded 3 knob Tube Driver. And the 5 knob doesn't make any special noise to me. I can't say much about the 1 on my board cause I have a BBE mini sonic stomp starting my board and a silent-modded 10 band E Q ending my board. It's a pretty quiet 16 pedalboard

in short. Effing, yea, its the real deal. YES

tunaXonXtoast it has a mid resistor, just no mid pot

All true and the reason I don’t do a low voltage tube pedal. Appreciate the detailed explanation 👍🏻

I can think of at least one player that would disagree with you. Well actually 4 David Gilmour,, Eric Johnson, Joe Satriani, and Edward Van Halen. You''ve heard of the "brown" sound, a term coined by Edward to describe a sagging power supply starving tubes for voltage . He describes it as the sound when the tubes get all "browned" out which is an electrical term for describing a power outage or a device that was experiencing a power outage or reduction. This is what he was recreating with the variac and is what starved plate designs are emulating. I have a Dean Markley Overlord which is a clone of this pedal and it is a straight up marshall in a box. I assume they changed some component values..Starved Plate designs aere not doing nothing just because thre is no published curves for them. Tube designers just could never fathom running a tube at that low of a voltage so never made curves or published curves for that range.