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Post by LVF on Jun 11, 2022 16:58:58 GMT -5
I've had some time to think about this mystery after I first noticed it. The mystery: Power tubes still lit up even when amp is unplugged. Just now looking at them, they are still lit up now for about 2 hours. Ok, as I said, I've had some time to think about this and for you tech types, you probably have a good answer for this. The pic shows the tubes lit even though the power plug, in the upper right, is clearly not plugged in. Now, this is a Sweetwater edition Twin Reverb just to be clear. Only had it for a little over a year. My, preliminary, guess would be a electrical component that is supposed to dissipate the electrons from the tubes when shut off. Something in that regard anyway. Or, The caps in the power section are just holding on to the electrons and this is normal. This is the first time I've noticed this. I just think there is some component error that is causing this. What do you think?  |
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pdf64
Wholenote
Posts: 557
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Post by pdf64 on Jun 11, 2022 19:24:53 GMT -5
It may be a reflection. The part that apparently seems to be emitting light is the getter. It’s neither heated or has any means of dissipating power. But it is very shiny  |
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Post by LVF on Jun 12, 2022 9:24:40 GMT -5
First of all, thank you for your answer.
The picture was taken with my Nikon D5300, no flash. The area photographed was in the dark, no lighting. All four tubes were lit in the same area. Whatever lighting that was available was blocked from getting through. I used a mirror to 'work around' the tubes to ensure it wasn't a reflection from a light source. Same condition. Even so, it is still possible that it could be a reflection and I'm unable to block it. With that, I've taken the chassis out
and somewhere along the line, there is no more light.
I will power it up with the chassis out and see if I get the same effect...
Powering up just the chassis with nothing plugged into it, reverb and speakers disconnected, normal power down occurrence. No light from tubes when powered off.
I've been waiting to post this as I work through this issue but, I need stop here while I attend other things. Be back for more of this a little later...
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Post by LVF on Jun 12, 2022 15:37:42 GMT -5
Back again and I have since reassembled the TRRI with still no explanation of this issue. So, this will have to remain a mystery as I can not repeat it. I will just have to say that in some way, it was a reflection of light as was suggested because the simplest answer is usually the correct answer.
This did open an opportunity to look at another minor issue I'm having with the tremolo input and the pedal. Sometimes the tremolo will not turn on when the button is pushed. It has to do with the jack connection I'm sure. The pedal works fine when plugged into the Silvertone. I can a get it to work on the TRRI if I fiddle with the connection until the amp barks [loudly!] and then, it works fine. I'm thinking the female jack on the amp has a connection problem. I'll look at this more closely some other time.
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DrKev
Wholenote
It's just a guitar, it's not rocket science.
Posts: 418
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Post by DrKev on Jun 12, 2022 15:50:45 GMT -5
If the amp is unplugged there is no way the tubes can be lit. The heaters on 6L6s require about almost 6 watts per tube, that means 24 watts of power for the quartet. If you are not plugged in, there is no way that can happen at all. None, zero, zilch, zip, nada.
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Post by jazzguy on Jun 27, 2022 21:57:39 GMT -5
Turn the lights off and look.
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Post by willie on Jul 19, 2022 11:43:35 GMT -5
Feeling heat on a tube/valve envelope is far more indicative of filament being lit...vision can be deceptive.
w
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Post by Peegoo 🏁 on Jul 27, 2022 12:20:43 GMT -5
Have we gotten confirmation this was a reflection of room light?
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Post by LVF on Jul 29, 2022 9:10:42 GMT -5
I can neither confirm or deny this issue....
Actually, I have come to the conclusion that it was reflection from another light source of which I could not identify. However, having moved the amp to another location, the alleged mystery lighting disappeared. I leave it to you, to draw your own conclusions...[creepy music plays].
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Post by Mike the marksman on Aug 3, 2022 13:52:05 GMT -5
And the heaters are not connected to any capacitors that can store voltage. They're connected directly to the 6.3VAC winding on the power transformer. No AC? No glow.
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