Blackstar ht-dual tube swap

[Gatter91]

The tinkering bug has struck again!

I've owned a blackstar ht-dual pedal for around 18 months now and absolutely love it. A short while ago I found an NOS mullard on the cheap and replaced the original tube with that, which did make a marked improvement.

What I wanna know is could I use another type of tube, such as a 12AT7 or 5751 to clean it up or give a different type of gain? Is there anything that would inherently make this impossible or if I would end up with a hot melted blackstarry blob on my garage floor?

[andrew__t]

Hello, I asked a vaguely similar question over on the offset guitars forum this week too. I've had my ht-dual for about 3 years and it's my main overdrive but it's starting to sound a bit thin, so I'd like to swap out the valve if possible. One of my criticisms of the pedal is that there are not separate tone controls for each channel and I find channel 2 is not as distinct as channel 1 and doesn't cut through that well when playing with the rest of my band.

[fretman_2]

Coming off the top of my memory...the 5751 can be used as a sub for a 12AX7. I put some of those in my Peavey Classic 30 at one point and liked them. The 12AT7 has less gain (mu) than the 12AX7 so will change the character of your pedal. The 12AX7 has a mu of 100 and the 12AT7 60.

Originally Posted by Gatter91

The tinkering bug has struck again!

I've owned a blackstar ht-dual pedal for around 18 months now and absolutely love it. A short while ago I found an NOS mullard on the cheap and replaced the original tube with that, which did make a marked improvement.

What I wanna know is could I use another type of tube, such as a 12AT7 or 5751 to clean it up or give a different type of gain? Is there anything that would inherently make this impossible or if I would end up with a hot melted blackstarry blob on my garage floor?

[Mojotron]

I used 1960's era Mullard 12AT7 tubes to clean up Tube Drive pedals - worked pretty well, but not as well as just switching to an Ei 12AX7 (Gold/Elite/qualified) instead of a 1960's Mullard 12AX7. It tough to find really great tubes these days, but the new GT/Mullards are pretty good.

This thread may actually be better served in the other forum.

[Gatter91]

Andrew that was exactly my thoughts too, I can only really get one channel to sound good at the expense of the other, it's really irritating! Other than that I love it.

Thanks, I'll have a look at an Ei. Preamp tubes aren't drastically expensive anyway so I'm up for swapping a few around. If nothing else it's always good to have some spares! And I just put it in this section as I have the crappy iPhone app for tdpri and it was the closest I could find :)

[Gatter91]

Bit of a bump, I replaced the tube with an Ei, it sounds quite dark. Haven't tried it out at volume yet but I'm in two minds... Channel 1 seems smoother but channel 2 just seems a bit flabby! Almost a nasty metal tone, not what I'm after! Reckon it might be just a dodgy tube? I hear their QC is a bit hit and miss. I've just ordered a gold pin JJ from KarlTone on eBay, I'll see how that goes.

[alscort93]

You might want to post this in one of the amp forums instead of the guitar building forum, I got the same app, pretty easy to find the other forums on here. The Shock Brothers DIY amp section could probably help you more.