Convert Seymour Duncan Twin Tube to 12ax7s.......................

[Jeffblue]

I heard a youtube video of someone who had converted their Seymour Duncan Twin Tube Classic for use with 12AX7s. I liked what I heard. I am considering the same thing with my Twin Tube Blue. I have already mapped out the connections on the PC board and made the necessary drawing for wiring a noval 9 pin socket to match the appropriate wires to pin lugs. Has anyone else done or considered this?https://youtu.be/LA2Kk7LREvE

[Mincer]

Re: Convert Seymour Duncan Twin Tube to 12ax7s.......................

Actually, the first I've heard of it...what don't you like about the Blue that you'd want to change it?

[Jeffblue]

Re: Convert Seymour Duncan Twin Tube to 12ax7s.......................

I like the Twin Tube Blue, but I prefer to roll tube types whenever I decide when I want to change. All of my other tube pedals utilize 12a*7 tube types and I have a stash of NOS tubes. Having a complicated pencil tube that has to be soldered in to change out seems like more trouble than it's worth. Typically I think everything can be improved if you have the room and inclination.

[Mincer]

Re: Convert Seymour Duncan Twin Tube to 12ax7s.......................

I like the Twin Tube Blue, but I prefer to roll tube types whenever I decide when I want to change. All of my other tube pedals utilize 12a*7 tube types and I have a stash of NOS tubes. Having a complicated pencil tube that has to be soldered in to change out seems like more trouble than it's worth. Typically I think everything can be improved if you have the room and inclination.

That's cool. I am all for experimenting. I was just thinking you had a sound you were going for. I had a regular Twin Tube for years, but I've never used the Blue version. Have you compared them? How are they different?

[Jeffblue]

Re: Convert Seymour Duncan Twin Tube to 12ax7s.......................

That's cool. I am all for experimenting. I was just thinking you had a sound you were going for. I had a regular Twin Tube for years, but I've never used the Blue version. Have you compared them? How are they different?

The Twin Tube Classic, I believe, is the model you owned. The Blue uses tubes that are less gain so the Blue is more subdued. I've heard the Classic only on youtube videos, never played one. To my ears, the pencil tubes just don't sound as good as the 9 pin noval tubes.

[Mincer]

Re: Convert Seymour Duncan Twin Tube to 12ax7s.......................

Yes, the Classic...that was the one. It had a tight bass thing going on, and more gain than I normally use.

[Jeffblue]

Re: Convert Seymour Duncan Twin Tube to 12ax7s.......................

Yes, the Classic...that was the one. It had a tight bass thing going on, and more gain than I normally use.

And that is the issue I have with the Blue is that there is no ability to change the kind and amount of gain structure due to the limitation of the included tubes.

[devastone]

Re: Convert Seymour Duncan Twin Tube to 12ax7s.......................

I would just make sure the heater circuit is the right voltage and can supply enough current for the 12AX7 heaters. If the 12AX7 heater is pulling a lot of current, the circuit might work fine for a while then overheat, I've had this happen on a 6L6 amp that I rewired to be able to use EL34s, didn't even think that the heater current would be different enough to cause a problem.

[Jeffblue]

Re: Convert Seymour Duncan Twin Tube to 12ax7s.......................

I would just make sure the heater circuit is the right voltage and can supply enough current for the 12AX7 heaters. If the 12AX7 heater is pulling a lot of current, the circuit might work fine for a while then overheat, I've had this happen on a 6L6 amp that I rewired to be able to use EL34s, didn't even think that the heater current would be different enough to cause a problem.

Good point, thank you for your interjection. I'll review the power supply amperage and the the tube filament requirements.

[Jeffblue]

Re: Convert Seymour Duncan Twin Tube to 12ax7s.......................

The good news is both the 6111 sub miniature tubes and the 12Ax7 heater current draw are both 300ma.

[jeremy]

Re: Convert Seymour Duncan Twin Tube to 12ax7s.......................

im curious how this works out for ya. i have a ttb and i dont love it. the ttc i find much more useful, although independent tone controls would be nice on both models

[tone4days]

Re: Convert Seymour Duncan Twin Tube to 12ax7s.......................

im curious how this works out for ya. i have a ttb and i dont love it. the ttc i find much more useful, although independent tone controls would be nice on both models

this is how i feel about my TTC which i really like ... the red channel needs the treble backed off to suit my preference but if i dial the tone knobs for the red channel, the green channel is a little lacking clarity for dirty-ish chords ... i've tried to work around it by using the tone knobs on my guitars but its always a compromise and not as easy as stepping on one button

i'll be bummed if my TTC ever gives up the ghost because of the tubes - its gets about 3 hours a week

really makes the Blues Jr come alive
good luck with the mod ... what are you thinking for the physical enclosure needs of 12A*7 s?

[Jeffblue]

Re: Convert Seymour Duncan Twin Tube to 12ax7s.......................

im curious how this works out for ya. i have a ttb and i dont love it. the ttc i find much more useful, although independent tone controls would be nice on both models

I agree, the ttb isn't something that tonefully holds my interest. I know it could be better. I think the basic difference between the Blue and the Classic is the tube type. I think the 12A*7 tube family is the answer and possibly mixing them....say a 5814A (military grade 12AU7 for the clean mode for transparency) and maybe a 12AY7 or 12AX7 for the dirt side.

[Jeffblue]

Re: Convert Seymour Duncan Twin Tube to 12ax7s.......................

this is how i feel about my TTC which i really like ... the red channel needs the treble backed off to suit my preference but if i dial the tone knobs for the red channel, the green channel is a little lacking clarity for dirty-ish chords ... i've tried to work around it by using the tone knobs on my guitars but its always a compromise and not as easy as stepping on one button

i'll be bummed if my TTC ever gives up the ghost because of the tubes - its gets about 3 hours a week

I am not going to try to change anything about the tone circuitry because I don't want to destroy my pedal. If you open up your ttb pedal you'll see that the 6111 tubes are wired in succession and if you were really, really careful and you are fairly good with soldering, you could change them out. You could even change to 6021 tubes to match or get closer to the Classic tones.

really makes the Blues Jr come alive
good luck with the mod ... what are you thinking for the physical enclosure needs of 12A*7 s?

I am not going to try to change anything about the tone circuitry because I don't want to destroy my pedal. If you open up your ttb pedal you'll see that the 6111 tubes are wired in succession and if you were really, really careful and you are fairly good with soldering, you could change them out. You could even change to 6021 tubes to match or get closer to the Classic tones.

I opened up my ttb and physically set a 12AX7 in there to see how it would fit. It will be close and I would need to move the tube socket extremely close to the original tube connections. If there still isn't enough room, I'll add a "Gasket" or rubber seal the width of the front of the pedal to create a gap if you will for room for the tube and socket.