"I leave my amp on for 30 days...."

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Fastforded

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First thanks for all the help... second, this would be a tube question, not really about the amp or manufacturer...

im watching this video with eddie van halen talking about making/designing his 5150 tube amp.
https://www.youtube.com/watch?annotation_id=annotation_971006&feature=iv&src_vid=YVdryLntfD8&v=3lRGB0YwAsU

its a 5150 series amp witht he following tubes:
Preamp Tubes: 7 JJ ECC83 (12AX7)
Power Tubes: 2 JJ 6L6


in the video he says "i leave my amp on 30 days to "crash test my stuff"

simple question... don't all the tubes get worn (and sound bad )after 30 days being on? I have no idea if he changes the tubes, say, every week, but for the sake of argument let us assume he doesn't change the tubes.

that is 24hrs x 7 days x 4 weeks= 672 hours "on"

now, this is his "home studio amp" so i guess his 'tone" isn't that critical as he probably has other "recording" and "gigging" amps..

but all that aside, wouldn't this really "wear out" the tubes?

any thoughts appreciated

Bonus Question:

for anyone who is into amp design, construction, modifying, etc.
In the video, he also says the transformer is the "secret" to this amp, and tone... any thoughts why h values the transformer so much? Why is the trans so important? the way it changes ac to dc changes something about the power going into the tubes and that changes the entire sound?

thanks, any thoughts appreciated.
 
Leaving the amp on would simply have the effect of "burning in" the tubes. Some vendors offer tubes that are burned in, albeit for only 24 hrs. Typically, tubes can last for many thousands of hours, and letting them idle for several hundred hrs might be a bit extreme, but certainly will not wear out the tubes. This would also check for any tubes that might fail early, insuring that the tubes will likely work for a long time.

As for the transformer, EVH is likely referring to the output transformer (OT), which does have a big impact on the tone of an amp. There are upgrade OTs for many types of amps, and the tone can be changed/improved with an OT swap. A transformer does not change AC to DC, that would be a rectifier that changes AC to DC. A transformer changes the level of AC, either higher (step up) or lower (step down) or both. In the power transformer (PT) of an amp, the incoming line voltage (120 VAC) on the primary is changed to several voltages of various levels on the secondary, such as 366 VAC for the high voltage supply, 6.3 VAC for the heater supply, maybe 50 VAC for the bias supply, etc.
 
Leaving an amp in standby disconnects the high voltage from the tubes, therefore no current through the Cathode. "Cathode poisoning" doesn't even occur in an instrument amplifier anyway, this is largely a myth as far as instrument amps are concerned, and could only occur if there is high voltage applied to the tube, meaning current is flowing, so being in standby doesn't hurt the tubes at all, and would not even wear them. In standby, only the heater of the tube is on. The OP referred to EVH leaving the amp "on", no reference to it being in standby, although that could be the case. Using the standby in an amp is beneficial for tubes, and I routinely leave my amps on for hours, sometimes all day, and I use standby when I'm not playing. I also routinely get many, many years of use from my tubes, and this is no coincidence. :wink:

The worst thing that you can do for any electrical components is to turn them on and off several times, as it is the heating and cooling cycles that are detrimental to electronics. Once turned on and warmed up, it is beneficial to leave your amp on, and use the standby, that is what it is for. 8)
 
shimmilou said:
Leaving an amp in standby disconnects the high voltage from the tubes, therefore no current through the Cathode. "Cathode poisoning" doesn't even occur in an instrument amplifier anyway, this is largely a myth as far as instrument amps are concerned, and could only occur if there is high voltage applied to the tube, meaning current is flowing, so being in standby doesn't hurt the tubes at all, and would not even wear them. In standby, only the heater of the tube is on. The OP referred to EVH leaving the amp "on", no reference to it being in standby, although that could be the case. Using the standby in an amp is beneficial for tubes, and I routinely leave my amps on for hours, sometimes all day, and I use standby when I'm not playing. I also routinely get many, many years of use from my tubes, and this is no coincidence. :wink:

The worst thing that you can do for any electrical components is to turn them on and off several times, as it is the heating and cooling cycles that are detrimental to electronics. Once turned on and warmed up, it is beneficial to leave your amp on, and use the standby, that is what it is for. 8)


Thanks for the time. Appreciate the info...
 
shimmilou said:
Leaving an amp in standby disconnects the high voltage from the tubes, therefore no current through the Cathode. "Cathode poisoning" doesn't even occur in an instrument amplifier anyway, this is largely a myth as far as instrument amps are concerned, and could only occur if there is high voltage applied to the tube, meaning current is flowing, so being in standby doesn't hurt the tubes at all, and would not even wear them. In standby, only the heater of the tube is on.

Yea...I've heard many views on this! Here's the thread I was referencing:

http://forum.grailtone.com/viewtopic.php?f=4&t=19382&hilit=cathode+poisoning
 
Eddie said he not only left the amp on, but he left the guitar plugged in and the amp fully cranked for "a month." That allowed for the guitar to feedback continuously for that length of time. If the amp doesn't blow, it passes his test. He went on to say he performed that same test with every revision they made for his EVH amps. Not 100% sure I believe that.
 
jnoel64 said:
Eddie said he not only left the amp on, but he left the guitar plugged in and the amp fully cranked for "a month." That allowed for the guitar to feedback continuously for that length of time. If the amp doesn't blow, it passes his test. He went on to say he performed that same test with every revision they made for his EVH amps. Not 100% sure I believe that.

Well the amp does have a standby and maybe he turns down the guitar volume so it doesn't feedback...

And saying he ford leave it fully on I wonder if the tubes are worn and start soundin like crap?

Not really sure what the measurable life of the tube is?

And what wears out faster? Preamp or power tubes? Or all the same?

And I could believe he does that as long as everything's free for him who cares?

Must be nice to test an amp like that...and just not care what happens...
 
He is a little bit......out there. No telling what other kind of goofy stuff he does. :|
 
Well he probably hasn't actually paid for an amp in the last 30yrs.
Personally I wouldn't leave a tube amp on unless I was going to be close-by. I'm that way with about any machine or high-heat electronics.
Call me paranoid.
 
According to Mesa, power tubes wear faster than preamp.
"If you play at moderate levels 10-15 hours a week
Power Tubes will generally last 1 - 1.5 years.
Preamp Tubes will generally last 2 - 3 years."

http://mesa.stores.yahoo.net/whattubtotub.html

And, in the video, Eddie said he left the guitar feeding back for "a month." Yeah, if he doesn't have to pay for it, then why should he care? Even if he DID have to pay for it, why should he care? He can afford it. :wink:
 
jnoel64 said:
According to Mesa, power tubes wear faster than preamp.
"If you play at moderate levels 10-15 hours a week
Power Tubes will generally last 1 - 1.5 years.
Preamp Tubes will generally last 2 - 3 years."

http://mesa.stores.yahoo.net/whattubtotub.html

And, in the video, Eddie said he left the guitar feeding back for "a month." Yeah, if he doesn't have to pay for it, then why should he care? Even if he DID have to pay for it, why should he care? He can afford it. :wink:

I was told 1-1.5 years for power tubes and preamp tubes either work or don't so replace them when they don't work anymore...

It would be cool to see something like a comparison between worn tubes ad good tubes... Or something that indicates the tubes needs to replaced....

I have some new tubes for my amp and I'm trying to figure out how I can judge or gauge any differences when I switch out the old tubes for the new ones... Any suggestions appreciated
 
Listening is the best test. If your sound is less than what it used to be, maybe time for new tubes. There is really no set limit on tube life, they can fail immediately, last 100 hours, last thousands of hours, even last for decades. I am a little leery of recommendations to replace tubes every ________ (insert time period), especially from someone that sells tubes. :wink:
 
shimmilou said:
I am a little leery of recommendations to replace tubes every ________ (insert time period), especially from someone that sells tubes. :wink:

Yep I was thinking the same thing...
 

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