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haha gitardrumblethump said:I've never heard that from my tube guru, but some gitard might say something like that.![]()
i get the whole shutting down and powering up with the standby switch and all, just didnt know if i had to play the tubes for a certain number of hours before i really push them.Blueszilla said:I have some experience with large power amplifier tubes, such as the intermediate and final pa sections of large transmitters. These tubes (mfd by ITT) required several hours of burn-in and monitoring of filament currents. The 'break-in' period, as explained to me, was mainly for filament stabilzation. Filament output will vary initially, then reach an equilibrium after time. In push-pull output stages, it is important that each tube be "matched", in terms of output,with it's partner for proper waveform shape, and balanced transmission to the antenna.
That said, I don't know that amplifier tube manufacturers recommend a burn in period and if it is just a single tube stage there is no matching to do. OTOH, it certainly wouldn't hurt to leave it on filament only (standby) awhile. It used to be that you waited a bit after turning the amp on in standby to let the filaments warm up, come to operating temperature, then apply the bias. Might make your tubes last longer. Also waiting a bit with the amp in standby lets it come down in temp a little before shutting the power off. I have an amp with a single tube pre and it doesn't have a standby switch, so bias is applied with the preamp volume control. I turn this down to zero before turning the amp off.
The filaments in a tube are somewhat like whats in a light bulb, though physically stronger. The longer they're used the more brittle they become. A slow warm up and warm down will get the most life out of them.
rumblethump said:I must respectfully disagree about the standby being used in the turn off and turn on of an amp. Here again, my tube guru
(Gary Donovan) who has custom built several tube amps for Robert Cray has told me that the standby only needs to be used for breaks (so you don't have to wait for the tubes to heatup, turning tubes on and off causes more wear) and that using the standby switch on startup or turning off does not have any effect on tube life or performance. Having the amp biased properly, and having a matched set of output tubes has the most effect on tube life and performance.

jabberwock777 said:Unless you're getting your tubes from a company which specifies that it matches and burns your tubes, they're not burned in.
Whether they require them or not is a different matter,
but the factories in China, Russia, Yugoslavia, and the Czech Republic do NOT do this. They simply make tubes up to a given company's specs and standards, which may or may not be high, and sell them.
Aspen Pittman's American factory matches and burns their GE reproductions, but only because Groove Tubes matches and burns all their tubes anyway for consistancy.
The best way to find out is ask the company involved where they get their tubes, and what they do with them before assembling the product.
popinfresh said:So.. say I play a 1-2 hour set.
I switch the amp on in standy and after waiting a little bit, start playing the gig.
Halfway through, we have a break for 15-20 minutes. Do I leave the amp on with the volume down, or in standby?
We start playing again, then I turn it straigh off, and afterwards flick the standby switch so it's ready for the next time I play.
Right?
Stanby wont cool down the tubes, it will just keep them at temperaturecheezewiz said:Lord Valves tube FAQ states you SHOULD NOT use standby on breaks. It causes the tubes to heat up/cool down each time you use it. He said its better to leave it on (obviously after the intial warmup), and then cool down using standbye at the end of the night.
this is all i wanted to hear.Blueszilla said:As to the original question, if the manufacturer doesn't provide specific instructions about a 'break in' period, then I would have to assume none is needed.