Chaging tubes... Timing question (When?)

[Benkenove]

Hi guys,

Got a doubt... may an amp (in this case a Herbert) need change tubes even when they "light up" ???

I mean, is there any "rule" where I should know when to change them (apart of the ear I know... but as these things go progresive, I really dont know 100% for sure).

I'd like to know it the indicative would be, for example, if some tubes dont light, change... or if it's possible to be bad even when they light up ???

Let me know your thoughts.

Ben.

 

[steve_k]

The $64,000,000 question! Guess Peter can start putting a reset hour-meter on the amps! Re-zero at tube change.

Much depends on how much you play, how hard you drive the amp, and the QC of the tubes themselves. If I was happy with the tone and my amps purpose was to stay at home and give me something to jam/record on, then I would run them to failure. If on the other hand, the amp was on the road every night, I would change them at least two or 3 times a year as insurance.

 

[Peter Diezel]

Thanks, Steve

 

[steve_k]

Thanks, Steve

what about the tube hour-meter? another industry first to go along with channel inserts!

steve

 

[i.ak]

Thanks, Steve

what about the tube hour-meter? another industry first to go along with channel inserts!

steve

Shhh!!...Quiet Steve!!

...Or someone from the notorious manufacturers of those not-so-tubeish tubeamps with those wonderful modern "virtual or digital tubes" might hear your brilliant business idea. This would definitely once again hurt the poor kids' wallets. Hmmm...maybe these hour-meters' rolls should be made from 99% pure gold with 1% of special highly expensive secret spaceage incredient so that the tone would not be ruined.

I want my VH4 to speak to me with demonic voices during the breaks between songs and command me to "feed me with new virgin tubes...immediately". Then there would not be any doubt when the time has come.


And as an answer to the original question here, I would say that Steve stated it pretty much perfectly. If the sound is good and the amp is responsive and operating normally your fine. I have noticed, that quite often the first signs of worn tubes is some sort of lack in dynamics, which is often followed by brumming or hizzing sounds rather soon.

On very general level, I would say that I usually change my power tubes once a year. This is of course dependant on the type of the power tubes (e.g. 6550 Vs. EL84), quality of the individual tubes, amount of playing in relation to volume levels and bias range. Preamp tubes seems to last "forever" and when failing they definitely give you a sign (loss of gain or complete signal, terrible squaling and feedback, "boiling" sounds).

And yes, the tubes may glow and still be absolutely defective. Especially in preamp section, you may investigate by tapping them with pencil (amp + volume on) and by changing/swapping them one by one.

 

[Benkenove]

Hey Thanks for the answers...
That is basically one of my biggest doubts (I'm a totally nerd about tubes and technical issues... I just play man )...

But I needed to know if it was possible to have "bad/broken" tubes and still glowing up... so it's not like notmal light lamps , great to know.

I think it's time for me to change all the tubes in my herbert, althoguh I'll have to wait a little, because retubing this "bitch" is not cheap at all !!! but I know it worth it

I think I'll give a try to the 6550... and see what happens

Thanks again !!!

 

[stefvorcide]

I want my VH4 to speak to me with demonic voices during the breaks between songs and command me to "feed me with new virgin tubes...immediately". Then there would not be any doubt when the time has come.

THAT WOULD BE SO GREAT. the crowd would have a great time too