i don’t know much about soldering but can i see the back of your board? I sometimes have a weird thing where if i touch some components like the jack connectors i get funky results, (i know i probably shouldn’t do this but it was one time!) probably some weird grounding issue as you said…i don’t know…you said you re-flowed but i find it weird that it doesn’t work, i can compare it to mine visually as mine works with no faults that i know of but that’s as far as my “expertise” will reach lol
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Should make no difference, these are for our purposes basically identical.
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Hey is that tube shiny metal on the inside of the top or is it like a white haze? If so the vacuum is broken and the tube will not work
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Hmm it’s like white haze so it’s broken tube. Thank you from bottom of heart that my resoldering mysery is finally over 
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Yeah blown tube was my first thought, although I would probably expect the heater to burn out ( is there any continuity between 4-5-9 ( may act oddly resistance wise IN Circuit )
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Yes that happens also but you can see in the 3rd picture that the tube has lost it’s vacuum. You can tell by the white color. It’s supposed to be shiny metal color.
It can happen when a pin gets knocked, or when you twist the tube when pulling it out of the socket. Age is not very often the cause.
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Yeah the tube is toast. Really need to socket this one. I didn’t, accidentally left it on over night and the tube was white the next morning. Could have just pulled and replaced if I would have socketed it but got in a rush. Then trashed the traces getting it out.
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Thank you everyone for tips and support!
Yeah there is continuity. Can I ask what possibly could happened?
Guess I got to be more careful next time. It was my first try with tubes. So basically I was just idiot with solder iron Could it happened by excessive heat while I was soldering it down?
That gonna be nightmare. Have to find man with desoldering gun because I’ve got only desoldering iron and first tries didn’t bring much success even with flux. Maybe I just reorder the pcb and will wait for sockets
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Dear guys hello.
I’ve built this thing in any possible way except Sam’s pcb version.
No matter what, I always have noises when I turn the gain pot up and down, and when I turn it all the way up I get this pop like he reached its max point (just a bit from 3/4 position up) and from this position up its sound very strong drive .
I guess cause of the stripboard version and air wiring, I get all sort of noises EM interference etc.
Did any of you maybe came a cross everything I was referring too?
BTW, I’m using 12AU7 not 12AX7
Cheers,
Isak.
Yes i guess uneven heat can also be the cause.
I’ve never soldered a tube before, i always use sockets 
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It should work fine with 12au7, i use it as well.
What kind of noises are you referring to?
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Thank you for your reply.
I have this high frequency at 1.6khz and low frequency at 50hrz that can totally say its GND issue, you can see the peaks level in the RME’s totalizer.
and I’ve uploaded a short vid clip the noises i hear in all of my builds, even when i built the original one 8 or 9 years ago, the same issue.
https://streamable.com/g11p3q
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Glad to hear you got it sorted, hopefully a new tube will put an end to it
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BTW do you get self osc with your 12au7?
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Welcome to the forum
For me there’s only 3 electrolytics cap in this circuit
and I can see 7 on your build (video)
what schem do you used ?
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when nothing is plugged into the input it self oscillates
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Ok i watched the video, the noise of the gain pot is pretty weird. Is it a new pot or is there any chance it is dirty?
The 12au7 is pretty low gain, i think there’s little chance of it oscillating in this circuit.
(Except that as sam mentioned above, if there’s nothing in the input, the output gets fed back into the input making it oscillate)
It does look like there’s no power supply bypass capacitor on the opamp. Try adding a 100nf or so capacitor between the power pins if you haven’t already.
You can try a 10pf capacitor between plate and grid of the tube (pin 1 and 2 and pin 6 and 7). It’s a popular trick in tube amplifiers but i think it shouldn’t be necessary.
I don’t now what power supply you are using but tube heaters use a lot of current (150ma at 12v) and can make your power supply noisy if it’s running near its limit. Make sure one end of the tube heaters is grounded, at only one point, preferably not the same point as your audio ground.
Also, what sam said above makes a lot of sense. I built mine a little different so it doesn’t oscillate with nothing plugged in so i didn’t think of that
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Thanks Dub
I use the regular scheme, the 4 big ones are 100uF filter caps in parallel with one another, the reason for that is the switching power supply I’m using it have ripples.
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Hi Sam,
I’m sure cause of the strong amp, I’ve built similar things with opamps that self osc’s.