#1
Evening/morning folks (pick one according to your time zone)

Small spot of bother.
My amp is a Marshall AVT50xt, A hybrid amp with a single 12ax7 preamp tube.
just for curiosity's sake, I'd like to change said tube (I have a JJs 12ax7 just waiting
for a new home).

Thing is, I'm definitely not a tube amp guy, never owned one, never changed one
before. That said I know how to change a preamp tube. wiggle in-wiggle out.

The problem is, How the **** do I get to the tube?

also is there some kind of electric shock risk here? and is it worth changing the tube at all in a hybrid? I have heard this amp in particular benefits from a tube change, but could it benefit THAT much? Would I even notice?

Thanks all.

Short version for the 'tards who can't read

1. Marshall AVT50xt
2. Would like to change preamp tube
3. Where is preamp tube?
4. Will I die
5. Will I notice improvement

Thanks.
#2
there should be screws on the top, remove these screws and it should be able to slide out. then you should be able to see the preamp tube. It will slighty change the gain structure(making it smoother or fuzzier), and could get more gain depending on the preamp tube.

And you will not die lol
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Schecter C1FR
MXR M-109 EQ
#3
Changed my tube on my old VS100 a while ago. Took maybe 10 minutes and was super easy.
Epiphone Les Paul Standard Plus
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#4
Yeah I figured that was it. I took the 4 screws out, had a sudden case of the fear, panicked and spent 20 mins trying to screw them back in. I get nervous around electrical equipment.

So there's no high voltages I have to worry about or anything?
#5
just only touch the tube dude, and unplug the amp. you won't be doing anything that warrants extreme caution.
#6
Alright just an update.

did the job there 5 minutes ago. Relatively painless. The hardest part was getting the screws back in. The holes drilled in the cab don't line up with the holes in the Amp chassis AT ALL, so it took about 20 minutes to put 4 screws back in.

I haven't checked it out yet, but i'll keep you posted on whether or not there's any noticable improvement/decline in sound.

Also I'm assuming that metal wire around the tube is just to hold it in place?

Thanks for all ye're help. It's good to get some genuine help on these forums instead of the usual "I know more than you" bullshit that seems to be the Norm.
#8
Definitely won't be going near the guts!

As for sound improvement, Didn't notice much difference. There seems to be a nicer crunch on the gain channel. What i suppose you could call the high gain doesn't seem to be affected much. Then again I was playing through a single coil tele, so it's going to be a little loose anyway.

At least it was an experience, dipping my toes into amp maintenance. If i need to do it again, At least I know How.

Cheers guys!
#9
If you took out a short plate tube and put in another short plate tube you probably won't hear much difference. What you need to try is a long plate.

Hell, get an NOS tube for even sweeter tone (and longevity)
Parker PDF30
Vox VT40+
#10
there wasn't alot of difference because it was a pre-amp tube thats only for the overdrive channel

now if it was a power amp tube, it would have made a HUGE difference. and to be honest, i think an amp that uses poweramp tubes, with a dsp preamp, and a tube rec would probably sound better than most "all tube" amps out there.