BK Butler Tube Driver Tubes

Melldo

Member
Messages
416
So, i just bought a TD after seeing That Pedal Shows Valve OD episode. Thought it sounded really good on there but have found a lot of people online complaining about the stock 12ax7 in it. Is it really that bad? I'm in Scotland so it'll be a while until it gets here and I can try it out. Anyone have anything good to say about the stock version? Mine is the one with the bias knob. Does that help?
 

FuzzyAce

Member
Messages
2,595
I have one too. The stock tube is fine, but certainly don't let that stop you from experimenting. I've tried nos and newer 12at7s and that sounds great as well. I've settled on an older rca 12ax7 for the time being. Mine is without the bias knob btw.
 

Zeon45

Senior Member
Messages
1,713
I bought a BK Butler Tube Driver 5 years ago with the intention of swapping out the stock tube. Well, that stock tube is still in there and it sounds glorious.
 

kowalski440

Silver Supporting Member
Messages
1,708
I had a mid-90's 3-knob Tube Driver with a Yugo 12ax7 and it sounded great.
Then I swapped out that tube with a 12au7 and it went from great to incredible.
However, this is one of those experiences where your mileage may vary. Some folks don't like a tube swap, some do. I think it is largely rig dependent.
 

ellis dee

Member
Messages
2,894
i have a vintage champ...

i tried every tube i have with it, and i have quite a few.all old stock tubes.

so a month or so later, i decide to check what tube is in there.
it was a sovtek.

i never even new i had a russian tube. it sounded great so i left it in there.

i switched out the tube in my butler pedal. not sure what is in there now.

but i doubt it ,makes that big a difference.
 

Melldo

Member
Messages
416
Cool, thanks for the info guys. What would be the major change with 12ax7 to 12au7 would you say? Would it be less gainy? Less in the way of treble? Less compression? I don't know a lot about lots of different types of tubes I'm afraid. I wouldn't even know how to swap it out if I didn't like the stock one to be honest.
 

FuzzyAce

Member
Messages
2,595
Cool, thanks for the info guys. What would be the major change with 12ax7 to 12au7 would you say? Would it be less gainy? Less in the way of treble? Less compression? I don't know a lot about lots of different types of tubes I'm afraid. I wouldn't even know how to swap it out if I didn't like the stock one to be honest.
Generally speaking, yes a 12au7 would be less gainy. Notes will clip differently and the feel will change. Changing tubes of the same type will be more subtle, some have softer highs while others may be brighter. It's something you just have to experiment with to see what you like. Changing them out is pretty simple... unplug the unit from the wall first, just unscrew the bottom rubber feet and pull it open. Carefully and softly rock the tube ever so gently back and forth as you pull it away from the socket. You may want to have one hand on the edge of the circuit board to keep the board from moving too much. When you put a new tube in, just make sure the pinout is aligned with the socket. Pretty easy with 12a-7 types, and all these can be used in this pedal as well as a 5751. If you're unsure of tube type substitution then do some research, and if it's not a labeled tube I wouldn't use it. Hope this helps.
 

Black_Label

Silver Supporting Member
Messages
4,784
I've got an 80s BK Butler Blue Tube rack unit and the last time I pulled it out of my rack, I tried swapping about 4 or 5 tubes to see which sounded best. I can't remember which tubes I tried, but it would have been a mix of NOS Mullards and Amperex and TFK 12ax7s and 12au7s. In the end, the stock 12ax7 tube sounded best and I left it in. Smoother, less grainy.
 

Melldo

Member
Messages
416
As a side question, they also talked on TPS about how the Tube Driver has a high output impedance. In people's experience does that make running other pedals after it very difficult?
 

Ansur

Member
Messages
128
That can make it difficult, yes. On the David Gilmour forum there's a lot of useful information on that very subject.

Typically, running a buffer (or buffered pedal) right after the TD helps a lot.
 

Melldo

Member
Messages
416
Generally speaking, yes a 12au7 would be less gainy. Notes will clip differently and the feel will change. Changing tubes of the same type will be more subtle, some have softer highs while others may be brighter. It's something you just have to experiment with to see what you like. Changing them out is pretty simple... unplug the unit from the wall first, just unscrew the bottom rubber feet and pull it open. Carefully and softly rock the tube ever so gently back and forth as you pull it away from the socket. You may want to have one hand on the edge of the circuit board to keep the board from moving too much. When you put a new tube in, just make sure the pinout is aligned with the socket. Pretty easy with 12a-7 types, and all these can be used in this pedal as well as a 5751. If you're unsure of tube type substitution then do some research, and if it's not a labeled tube I wouldn't use it. Hope this helps.

Cool, so even if it was a 12au7 I was putting in it would just be a straight swap do you think? I've found some Yugo 12au7's online.
 

FuzzyAce

Member
Messages
2,595
Cool, so even if it was a 12au7 I was putting in it would just be a straight swap do you think? I've found some Yugo 12au7's online.
Yep straight swap. 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 another level of tweaking right there. I tried a few 12AU7 but ultimately prefer the 12AX7 and 12AT7 variants.
 

Liquid_Mojo

Silver Supporting Member
Messages
1,377
I've been using a Telefunken 12AU7 with the TD and it's perfect for me. Like someone else said, it's rig dependent. I also have a Yugo 12ax7 and it sounds great, but I prefer the 12au7.
 

fenderjapan

World Heavyweight Champion
Silver Supporting Member
Messages
5,872
I have tried many different tubes in my 5 knob... yugo, ruby, jj 12ax7, 12au7, even 12dw7. The different tubes do have small differences, I find certain tubes "feel" different in terms of sustain and how they interact with different parts of your rig and how they sound at different drive levels. I haven't found any surefire formula for what sounds like what but I know what my favorite tube is for it... JJ Gold Pin 12ax7
 

kooper156

Member
Messages
177
Maybe a small number of the original tubes might get bounced around and damaged in shipping. But having said that, I have never heard a BK that sounded bad with the original tube in it. You are probably referring to discussions between EJ clones who get into peeing contests over who has super ears like Eric.
 

GK72

Member
Messages
364
If I'm not mistaken, Mr. Butler added the bias knob option to help assist on adjusting the stock tube to your rig & preference. (?) :dunno
 

FuzzyAce

Member
Messages
2,595
If I'm not mistaken, Mr. Butler added the bias knob option to help assist on adjusting the stock tube to your rig & preference. (?) :dunno
Bias adjustment alone doesn't make up for tube type though. It will affect whatever tube is in there.
 
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Teleman76

Tubes-a-glowin
Silver Supporting Member
Messages
3,102
Cool, thanks for the info guys. What would be the major change with 12ax7 to 12au7 would you say? Would it be less gainy? Less in the way of treble? Less compression? I don't know a lot about lots of different types of tubes I'm afraid. I wouldn't even know how to swap it out if I didn't like the stock one to be honest.
Preamp tube gain chart

12AX7 100

5751 70

12AT7 60

12AY7 45

12AV7 41

12AU7 19

12DW7 / 7247 Dual triode one half had gain of 100, other half is 20
 




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