Hello All,
Here is one I have never come across. A haunted tube!
I have been going through some Type 26 tubes looking for a quiet pair. I plugged in one tonight that made the strangest noises. I mean spooky.
There were two basic noises:
1- a whale song like sound that was reverb soaked. Almost sounds like someone yelling "hello" from very far down a long a train tunnel.
2- (even more disturbing) a laughing sound. Almost like a dolphin-- that laughing noise Flipper made.
This would happen every two minutes or so. Each time the noise was followed by a soft low-level thump.
The bummer about this was that, otherwise, it was a nice quiet, hiss free, hum free tube! One of the best I've come across!
This 26 came with another as a pair. The other one lets out a steady soft thumping noise about once every two seconds.
What could cause this? Any ideas?
It has been humid and rainy here. Could the tube bases, which I believe is bakelite, absorbed some moisture?
Or are ghosts real?
Here is one I have never come across. A haunted tube!
I have been going through some Type 26 tubes looking for a quiet pair. I plugged in one tonight that made the strangest noises. I mean spooky.
There were two basic noises:
1- a whale song like sound that was reverb soaked. Almost sounds like someone yelling "hello" from very far down a long a train tunnel.
2- (even more disturbing) a laughing sound. Almost like a dolphin-- that laughing noise Flipper made.
This would happen every two minutes or so. Each time the noise was followed by a soft low-level thump.
The bummer about this was that, otherwise, it was a nice quiet, hiss free, hum free tube! One of the best I've come across!
This 26 came with another as a pair. The other one lets out a steady soft thumping noise about once every two seconds.
What could cause this? Any ideas?
It has been humid and rainy here. Could the tube bases, which I believe is bakelite, absorbed some moisture?
Or are ghosts real?
Thanks for your response.
Could be. But it only happens with that one tube. Other 26 tubes behave as expected.
Yep, may be the tube is just slightly faulty or out of spec in some way which causes the circuit to oscillate
Yes. Spiritphone. Voices from beyond. A friend is writing a book about a Spiritphone.
Thomas Edison’s Spirit Phone | Weird NJ
Thomas Edison’s Spirit Phone | Weird NJ
Odd noises are usually oscillation, heat expansion/contraction or inter-electrode shorting. That's the most likely three I can thing of.
Andy.
Andy.
If the oscillation is at regular intervals, it may be triggered by an external RF pulse. I once experienced this while breadboarding a 6V6G amplifier. The trigger was a cell phone on the workbench. It was exchanging the keep alive packets to the tower. This only happened with some older 6V6G tubes, not on the modern style ones. I increased the grid stopper resistor value.
Some #26 tube is more sensitive to radiated hum and RF, than others.
Some years ago I measured my -a few dozen- #26 tubes to choose the most "better" pairs, so IMHO even 20-30dB is imaginable.
In the same preamp the 50Hz hum difference (between the worst and best) was 30db!
Try to shielding (temporary) the tubes with aluminium foil. If it effective, any metal shielding device is usable.
Some DIYers use metal pencil holders:
Amazon.com: MaxGear Pen Holder Mesh Pencil Holder Metal Pencil Holders Pen Organizer Black for Desk Office Pencil Holders, 3 Pack: Home Improvement
Some years ago I measured my -a few dozen- #26 tubes to choose the most "better" pairs, so IMHO even 20-30dB is imaginable.
In the same preamp the 50Hz hum difference (between the worst and best) was 30db!
Try to shielding (temporary) the tubes with aluminium foil. If it effective, any metal shielding device is usable.
Some DIYers use metal pencil holders:
Amazon.com: MaxGear Pen Holder Mesh Pencil Holder Metal Pencil Holders Pen Organizer Black for Desk Office Pencil Holders, 3 Pack: Home Improvement
Doctor, It hurts when I lift 60 pounds with my left arm.
Then lift 60 pounds with your right arm.
I have 6 tubes, and one sounds bad.
Replace the bad sounding tube.
Knowing why a tube has a problem is one form of enjoyment.
Listening to a good tube amplifier is another form of enjoyment.
Just Sayin'
Then lift 60 pounds with your right arm.
I have 6 tubes, and one sounds bad.
Replace the bad sounding tube.
Knowing why a tube has a problem is one form of enjoyment.
Listening to a good tube amplifier is another form of enjoyment.
Just Sayin'
Thanks for all of your advice!
I've heard lots of noisy tubes, but this one was special. So I thought I would share.
The most unusual part is how distinctive the sounds are. An echo-soaked "hello" and that laughing sound were spooky, really, and I'm not superstitious at all! An if it happened only once, that would not have been unusual--heat expansion, random RFI, etc. But the repetition of the distinct noises was more puzzling.
PRR-- I think you are on the right track. I should use this tube to contact Thomas Edison and tell him I found a working device.
pcan-- The noise doesn't sound like cellphone interference. That is very well known to me.
Of course, filtered through whatever oscillation envelope is being created, who knows what it might sound like. I have played with many modular synths.
316a-- I will try lowering the voltage a little. I need to get some chokes for the filament PSU so I can do a pseudo-choke input arrangement and get more voltage flexibility. My mains voltage is high, here, and I am getting too high a voltage.
I can turn down the current via the Rod Coleman filament regs.
EL504-- do you know of a way to discharge tube static?
6A3sUMMER-- I know what you mean. Only problem is that this tube has the lowest hiss and hum of the fourteen Type 26 tubes I have. So if I could make it work, that would be ideal.
I've heard lots of noisy tubes, but this one was special. So I thought I would share.
The most unusual part is how distinctive the sounds are. An echo-soaked "hello" and that laughing sound were spooky, really, and I'm not superstitious at all! An if it happened only once, that would not have been unusual--heat expansion, random RFI, etc. But the repetition of the distinct noises was more puzzling.
PRR-- I think you are on the right track. I should use this tube to contact Thomas Edison and tell him I found a working device.
pcan-- The noise doesn't sound like cellphone interference. That is very well known to me.
Of course, filtered through whatever oscillation envelope is being created, who knows what it might sound like. I have played with many modular synths.
316a-- I will try lowering the voltage a little. I need to get some chokes for the filament PSU so I can do a pseudo-choke input arrangement and get more voltage flexibility. My mains voltage is high, here, and I am getting too high a voltage.
I can turn down the current via the Rod Coleman filament regs.
EL504-- do you know of a way to discharge tube static?
6A3sUMMER-- I know what you mean. Only problem is that this tube has the lowest hiss and hum of the fourteen Type 26 tubes I have. So if I could make it work, that would be ideal.
Perhaps the problem is that good type 26 tubes are starting to become 'Unobtanium'.
Long ago, I gave up designing amplifiers that use tubes that are no longer manufactured.
The exception to that is the type 45 (And actually, the current production "45" tubes are not really a type 45).
I only use real type 45.
Long ago, I gave up designing amplifiers that use tubes that are no longer manufactured.
The exception to that is the type 45 (And actually, the current production "45" tubes are not really a type 45).
I only use real type 45.
If it is static build-up, than i think there is discharging going on allready (at the regular intervals you are hearing). So you could call this a form of interelectrode shorting.
It is caused by stray electrons (the ones who miss the anode). Maybe the alignment inside this tube is not 100 %.
In the late 30's and early 40's, European tube manufacturers put skirts of metallic paint around the bottom part of some of their power tubes (like the EL3, EL5, EL6). The skirt is connected to a pin/contact of the tube. This pin/contact should then be connected to ground or cathode. The purpose of the skirt is twofold. It cools the downpart of the tube a little extra and it neutralizes static build-up on the inside of the glass of the tube capacitively (source: "Grondslagen van de radiobuizentechniek", 2e druk, Philips, 1946, page 48).
Maybe you could give it a try by wrapping some aluminum foil around the tube and connect it to earth.
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Do both tubes have identical internal construction and manufacturer - i.e. plates, filaments, grid?
Humidity would not affect the tube, since the elements are sealed inside a vacuum.
Does the noise eventually go away (this would indicate shifting internal structure during warm up) or does it persist while tube is powered up (oscillation)?
You can try using a constant current source instead of a votage source to heat the filament.