[Fitz]

Quote:

Originally Posted by GotNoRice Wow, what does it sound like when a Power Tube Arcs? Were you pushing the unit or did it just happen randomly during normal usage? Is this something that could cause damage to a connected headphone or an amp/speakers? Is this something of a common problem?

A sharp crack/pop that sounds a lot like when a lightbulb blows, in my case.

 

[Jbucla2005]

The only incident I had with a tube overheating was when trying to bias the power tubes myself with this attachment that went in between the tube and amp and to a volt meter. One of my tubes started to overheat and it blew a capacitor or resistor or something. No major damage was done, and the amp was repaired. But I will never try to bias a vintage amp alone again! I have left my Luxman on for years, for days at a time, and my MG Head on for many months without any problems.

 

[lini]

cosmo: Oh, I'm aware of tv sets being reported as a comparatively fire hazardous device (even though I've never personally heard of such a case) - but if one looks further into that, it's often enough also reported that most of the cases seem to be happening in stand-by mode with the standy-by circuitry being the culprit. So the tube assembly per se apparently isn't much of a problem.

Greetings from Hannover!

Manfred / lini

 

[trevorlane]

Quote:

Originally Posted by mulveling /img/forum/go_quote.gif I don't think there's exactly been a formal study on this subject. It can't hurt to be safe and turn the amp off before you leave the house - which is what I do. However, with all the headphiles and audiophiles using tubes, the reports I've seen of tube amps or tubes (from respectable manufacturers) failing voilently are very, very few and far between. They're pretty reliable on the whole. I have a friend who leaves his on for long periods during time which he often leaves the house - no mishaps so far. Still, perhaps it's safest to stick with well established amplifier models with a longer track record of reliability...time to upgrade to a Singlepower

I know this a few years late, and I'm sure mulveling now no longer considers SP to be realiable, but there is some irony in this.

Anyway, the tubes on my 337 occasionally make crackle noises. I didn't have a problem with this when I use Mark V guitar amp because it was normal for the amp, but what about on my 337?

 

[cegras]

ENIAC - Wikipedia, the free encyclopedia

Quote:

Some electronics experts predicted that tube failures would occur so frequently that the machine would never be useful. This prediction turned out to be partially correct: several tubes burned out almost every day, leaving it nonfunctional about half the time. Special high-reliability tubes were not available until 1948. Most of these failures, however, occurred during the warm-up and cool-down periods, when the tube heaters and cathodes were under the most thermal stress. By the simple (if expensive) expedient of never turning the machine off, the engineers reduced ENIAC's tube failures to the more acceptable rate of one tube every two days. According to a 1989 interview with Eckert the continuously failing tubes story was therefore mostly a myth: "We had a tube fail about every two days and we could locate the problem within 15 minutes."[10] In 1954, the longest continuous period of operation without a failure was 116 hours (close to five days).

 

[Junliang]

This thread is scaring the heck out of me.. >.<
Even the little dot II case.
Shouldn't II+ be II with all its hardware issues fix, like the fan power not enough ?
Because my entire rig, lappy, dac, speakers, headphones, amp, are on my study table, where there are tons of precious things around it.

The thought of anything coming close to it scares me >.<

*I want LD mk vi+ or viii+, tube amps...*

 

[Uncle Erik]

A home amp ain't ENIAC.

For one, ENIAC didn't use a lot of power output tubes, the way audio amps do. Power output tubes can get auite hot - leaving them on for days is not a smart idea. Further, there's no benefit from leaving them on other than running up your power bill and burning out your tubes, resistors and capacitors early. Changing a tube is easy. How many of you have changed a capacitor? It's not that hard, but not something anyone looks forward to.

As for the whole "it sounds better" nonsense, the sound changes because the components slightly go out of spec with heat. Instead of being at 100k, a resistor might go to 110k. The rest of the innards do the same. If you want to call somethig goin out of spec "better," feel free. However, understand that the longer the parts stay hot the sooner they will fail. How many of you want to open your amp and replace parts? How much would it cost to send an amp in for repair? You'd probably be out $50-$60 from shipping and another $200 at least for labor, then replacement parts, and you won't have your amp back for weeks or months.