It haves bypass 100nF bypass caps.
Even when i build the original Valvecaster one without Sam’s mods, i got the same results, noise on gain pot.
the gain pot is new, alpha B100K.
Bout the power supply I’ve changed that to LDO one with LM317 and LM337 high current one, the high frequency noise is gone, now the 50hz hum is present, and yes, the gain noise is still here.
I think normal PCB would be better for GND issues, flying wires never did good to audio.
I don’t think floating wires are a huge problem as long as you don’t run high power wires next to signal wires. Mine is built like this and i have almost no noise at all.
For the people that said they wanted to use sockets, i think this is the safest way to mount tubes in a panel, while still being visible/accesible.
I can remember replacing the gain pot with a 50k because mine wasn’t really stable at 100k. Low voltage tube circuits can be a bit hard to get to work right.
I think the 50hz is being picked up from somewhere. It can be a device connected to the safery valve, a device in the same socket that draws a lot of current (i have had noise issues when testing stuff when my soldering iron was still on), a ground loop, poor shielding.
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Please do tell me, how did you connect the gain pot?
mine → pot pins 1-2 chained and pin 3 of the tube connected to them, pot pin 3 to GND.
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Yes that is the correct way to connect it. It’s like that in schematic and also how i connected it.
It’s not really a gain control in the usual way, more like a cold clipper stage. It changes the symmetry of the distortion by shifting the operating point of the tube. It makes the current through the tube very, very low. To be honest, i don’t really like it. I always have it set very low.
I’m really confused about the noise that the pot makes though. 
Maybe someone else has any ideas?
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Hi Sam, ok I’ve ordered PCB and panel, maybe I’m doing something wrong.
Hope everything will be silky-smooth and no noise will appear on the gain pot.
Have a great weekend.
Isak.
Eventually I ordered PCB and panel, hope all will go smooth.
I thank you for your help 
Have agreat weekend.
Isak.
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Has the pcb arrived? If so how did it go ^^
Hi not yet, im still waiting
aww, hope it arrives soon and all goes well
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Thanks man, me too, ill update here when I’ll get it and hope I’ll time to build it instantly.
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4-5-9 are the heater filament. Not sure but I would expect it to burn out without the tube being sealed.
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Hey, curious if you ever tested these sockets out and if they were any good?
Hello.
I have completed my Safety Valve build, but unfortunately I’m not getting any audio when the module is engaged. With it turned off, the audio passes through. The LED for the module lights up - but the LED for the valve does not (it did briefly when I first turned the PSU on, but never again).
A video showing this in action: https://cdn.discordapp.com/attachments/946056629785342024/946438938665549854/VID_20220224_155819837.mp4
I am not entirely sure how to begin debugging this, so any input/help would be appreciated! I have not soldered in the tube yet. It is in there pretty tight.
Scratch that. Tried another valve and it works. Must be a dead valve. Glad I found that out with this module and not my guitar amp!!
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Glad you got a module to work out, and it happens to be the only one I haven’t been able to get working. I guess it is possible all of my vintage tubes are bad.
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Worth a try! I’ve had these valves kicking about in my flat for years, as backups for my guitar amps… but this seemed like a better use for them ha.
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A quick question: has anyone tried an ECC82 (12AU7) instead of ECC83 (12AX7) and are there any significant differences? My local dealer sells the ECC82 for 8 EUR and the ECC83 is 19 EUR 
I saw in the specs and from pictures that the ECC83 has a much more dense grid winding which lowers the crackdown and has higher inner resistance (results in a steeper current curvature at the same anode current, if I understood correctly).
Anyways… that’s just theory, so maybe you have some real-world experiences.
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If I remember correctly the 12au7 doesn’t have as much gain as the 12ax7 . but lowering the bias [ voltage on the heater filament ] will give you more gain which ever tube is used at least in tube amps , not exactly sure how that applies to this low voltage stuff .
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I prefer the 12au7 (ecc82).
It has less gain but a lot of the distortion comes from the op amp stage as well.
A lot of the 12ax7’s i tried it with sound kind of like a gated fuzz which i personally don’t really like. Also, my 12ax7’s are telefunken, philips and matsushita which are way to nice for a starved circuit
Generally, performance of the 12au7 is better at low voltage and was even used in car radios.
The lower internal resistance helps in starved operation because the current is already very low.
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I think you are right but got filament and cathode mixed up.
Lowering the cathode resistance creates a hotter bias and the total voltage swing, and thus theoretical gain gets higher
Increasing the cathode resistance lowers the swing and makes the signal clip harder on one side asymmetrical clipping gives a lot of even harmonics which are considered to sound pleasant.
Cold clipper stages in guitar amplifiers make use of this using a very large cathode resistor
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