Electrovibe Lamp Life

[Bricksnbeatles]

Anyone know what the expected lifetime of the lamp in an Electrovibe is? Bulbs like that aren’t usually rated with the expectation of being repeatedly modulated, so I’d imagine it’s not an especially considerable number of hours.

I’m guessing it’s not exactly a bad idea to mount a power-kill switch to the enclosure for when it’s not in use to prolong the lamp life.

 

[Big Monk]

Anyone know what the expected lifetime of the lamp in an Electrovibe is? Bulbs like that aren’t usually rated with the expectation of being repeatedly modulated, so I’d imagine it’s not an especially considerable number of hours.

I’m guessing it’s not exactly a bad idea to mount a power-kill switch to the enclosure for when it’s not in use to prolong the lamp life.

I'm gonna have to start writing all these tweaks down!

 

[Feral Feline]

4PDT — wired as per your usual 3PDT bypass, the 4th pole wired to take the bulb in/out with bypass.

 

[Bricksnbeatles]

4PDT — wired as per your usual 3PDT bypass, the 4th pole wired to take the bulb in/out with bypass.

That would be the perfect idea, if I wasn’t going to use a 4PDT already to have a “channel switch” jack so it can optionally be used with a JC-120 to disengage the onboard chorus/vibrato when kicking in the vibe, or so (via an internal jumper) you can have it so on certain amps (that use latching channel footswitches) the vibe also automatically switch channels so you can have either vibe cleans and dry dirt, or dry cleans and vibrato leads. Now I might make two electrovibes just to do it either way though.

 

[Gordo]

I'd think the constant on/off would be harder on the filaments than just letting it be. I've had a Voodoo Labs Vibe pedal for the better part of 20 years and no issues. Like any bulb it will fail eventually due to either burn out or mechanical trauma but that's true of virtually every part in the pedal.

 

[Bricksnbeatles]

I'd think the constant on/off would be harder on the filaments than just letting it be. I've had a Voodoo Labs Vibe pedal for the better part of 20 years and no issues. Like any bulb it will fail eventually due to either burn out or mechanical trauma but that's true of virtually every part in the pedal.

I mean isn’t the lfo effectively like a constant on/off somewhere between a rate of 0.5-10Hz? Even if it’s not truly dropping down to a true off state of 0v potential, it’s still a rapid fluctuation of voltage which is technically a less-than-ideal operating situation as far as the lifetime-rating goes. Maybe the bulb is just more resilient than I would expect, but I would think that removing power when the pedal isn’t being actively used for an extended period of time would lengthen the lifespan

 

[Betty Wont]

The electrolytic capacitors in the circuit have a shorter lifespan than the bulb. This bulb doesn't have the planned obsolescence of a household incandescent bulb.

 

[benny_profane]

Another issue you might run into is an audible pop if you engage/disengage the bulb with a switch. I'd suggest leaving it stock and replace it if necessary.

 

[fig]

If you think about it, when does (er did) an incandescent bulb usually fail? When the power is (er was) applied. I suspect the filament would handle varying current better.

 

[benny_profane]

The electrolytic capacitors in the circuit have a shorter lifespan than the bulb.

Although that is true, the lifetime rating for electrolytic capacitors is based on continual operation at specified ratings (i.e., voltage potential, temperature, etc.). Since pedal circuits typically put far less strain on caps than these ratings, you can expect electrolytic capacitors to last far beyond the stated lifespan.

 

[Gordo]

Betty Wont nailed it with the caps but got me thinking about the LFO. The LFO isn't a hard start/abrupt cutoff but a nice smooth wave. Well it's not smooth but that's just the Vibe magic. Regardless, it's not on/off. Put it this way: If your bulb burns out and I'm still alive, I'll offer to replace it.

 

[Gordo]

I know this will come back to haunt me, but gives me something to look forward to in my eventual retirement...

 

[Stickman393]

Hmm. This gets my technical brain going all question-y.

Thoughts:

I presume that oxidation is one reason a filament fails: after all, ever cracked an incandescent? That thing burns up real quick. Oxygen is the enemy, that's why the glass is pulled into a vacuum...or filled with an inert gas. Break that protective barrier, and poof.

But...that being said...heat would strike me as being the more common mode of failure. A household bulb filament gets HOT. 120VAC running through a 100 watt bulb will pull less than an amp. But another way of saying that ..would be that it generates 341 BTUs per hour.

For reference...1 BTU = the amount of energy required to raise the temperature of a pound of water one degree Fahrenheit.

For our metric homies...I dunno what to say. Aside from that the US is in the company of Liberia and Myanmar in that it uses measurements based off of a king's *clearly* exaggerated foot size. We haven't figured out that the metric system is superior yet because we're terrible at math and stubbornly stick to awful systems because of inertia. And other things. I won't get into it, history is weird.

ANYWAYS...

So...what's a good way to visualize a BTU? Shoot, light a match. The heat energy released from that match is around one BTU.

Ever stick your hand over a lit match? Like, right over it? Woof. One star. Do not recommend.

So...that lightbulb is putting out the rough equivalent of the stored heat energy of around 341 matches over the course of one hour. That's basically a match every 10 seconds. ALL EMITTED FROM AND LOCALIZED IN THAT TINY LITTLE WIRE. Holy sh*t!

So...heat. Heat generally causes materials to expand, and a reduction in heat causes materials to contract. It also speeds the process of oxidation...that combination is deadly. And those things would last for MONTHS!

So what's the deal, Stickman? Why you talking all this talk about heat?

Well...measure the current draw of a vibe pedal. The bulb is not the only device in a vibe pedal drawing current, but it's probably a sizable chunk.

Current times voltage equals wattage, wattage times 3.41 equals BTUs per hour. You now have your pedal's heat load.

I haven't done the math, but I imagine that the difference there is quite large. Sure, it's a smaller bulb, but the filament? I wonder how the the actual surface area dimensions differ...that could be taken into account as well.

So...yeah, It makes sense to me that a small, low draw, low voltage lamp like a vibe lamp would last for quite some time, especially if it was constructed well to begin with.

My .02 c.

 

[fig]

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