[toddc2]

Me too, with all the tubes being discussed.

I find most tubes need at least 30 seconds to heat up and stabilize. I have noticed some amplifiers sound noticeably better after an hour or two, but there could be many reasons: the tubes hit their stride or the amplifier hits it’s stride or (most likely) I’ve had a couple of beverages by then and my mood had hit its stride…

 

[mordy]

I find most tubes need at least 30 seconds to heat up and stabilize. I have noticed some amplifiers sound noticeably better after an hour or two, but there could be many reasons: the tubes hit their stride or the amplifier hits it’s stride or (most likely) I’ve had a couple of beverages by then and my mood had hit its stride…

An amp and set-up could sound good right away, but IMHO I noticed many times that everything sounds better after a while. And I am convinced that all metal tubes (the black ugly ones) need more time than glass tubes to warm up and sound their best.
And I am not speaking about those (somewhat) rare moments when everything sounds really really good... - just in general.

 

[toddc2]

An amp and set-up could sound good right away, but IMHO I noticed many times that everything sounds better after a while. And I am convinced that all metal tubes (the black ugly ones) need more time than glass tubes to warm up and sound their best.
And I am not speaking about those (somewhat) rare moments when everything sounds really really good... - just in general.

Beverage kidding aside, I have found my tube amps do sound better after an hour or two. I routinely turn my amps on an hour before I use them.

 

[gibosi]

5 minutes max for the tubes I have.

There were a number of folks in the Glenn forum who reported that their headphones were damaged by the loud popping sounds of 5998's as they warmed up. The consensus advice of those folks was to let 5998's warm up for about 30 minutes before connecting headphones to protect ears and headphone drivers.

 

[mordy]

There were a number of folks in the Glenn forum who reported that their headphones were damaged by the loud popping sounds of 5998's as they warmed up. The consensus advice of those folks was to let 5998's warm up for about 30 minutes before connecting headphones to protect ears and headphone drivers.

As an extra precaution with any tube change or new tube, I always use an inexpensive pair of headphones the first few minutes. You never know when something untoward will happen with an old tube...
After blowing an expensive headphone driver this routine doesn't seem so burdensome.

 

[leftside]

There were a number of folks in the Glenn forum who reported that their headphones were damaged by the loud popping sounds of 5998's as they warmed up. The consensus advice of those folks was to let 5998's warm up for about 30 minutes before connecting headphones to protect ears and headphone drivers.

30 mins is about all the time I get to listen some evenings. I have 6 5998's in my amp. Hopefully they don't all blow at once

I just let the meters get to their required values, wait a couple more minutes and then plugin the headphones. IF tubes are going to go, I usually find it's during the first few mins. I did once have a bad tube, and all the meters were going crazy at startup. I shut down the amp pretty quickly when that happened.

 

[CaptainFantastic]

I keep a list with all of my tubes with the various details like source, purchase date, condition, and also how it behaves in my amp. Recently a couple of 5998s seemed very slightly noisy and a 6SN7 was even more so. My spreadsheet indicated they should be perfectly quiet. Strange, I thought. Then I realized... my very nice tube socket savers (from the best source - not their fault, probably just bad specimens) were the culprit. Removed them and the tubes are perfect again. So there's that regarding tube noise too... funny how they only affected a few tubes, the majority were still perfectly quiet.

 

[Flisker]

I keep a list with all of my tubes with the various details like source, purchase date, condition, and also how it behaves in my amp. Recently a couple of 5998s seemed very slightly noisy and a 6SN7 was even more so. My spreadsheet indicated they should be perfectly quiet. Strange, I thought. Then I realized... my very nice tube socket savers (from the best source - not their fault, probably just bad specimens) were the culprit. Removed them and the tubes are perfect again. So there's that regarding tube noise too... funny how they only affected a few tubes, the majority were still perfectly quiet.

That is interesting info, I got 3rd tube amp today so I can test the tubes in all 3 and see if they behave the same or not.

 

[mordy]

That is interesting info, I got 3rd tube amp today so I can test the tubes in all 3 and see if they behave the same or not.

It should be possible to tighten the pin receptacles and perhaps clean the socket savers. The main problem I had in the past was that they held the tubes too tight and I had to struggle to get the tubes out of the socket savers.

 

[Odin412]

As an extra precaution with any tube change or new tube, I always use an inexpensive pair of headphones the first few minutes. You never know when something untoward will happen with an old tube...
After blowing an expensive headphone driver this routine doesn't seem so burdensome.

That's very good advice. I learned the hard way that some tubes crackle a bit at first, which translates to very loud scratching sounds in the headphone. I created a special TRS plug with two 300 ohm resistors to allow me to run new tubes for a while without a headphone connected.

 

[mordy]

That's very good advice. I learned the hard way that some tubes crackle a bit at first, which translates to very loud scratching sounds in the headphone. I created a special TRS plug with two 300 ohm resistors to allow me to run new tubes for a while without a headphone connected.

Do you think it helps to run tubes without the load of headphones for a while? I know somebody who has a setup where he lets new tubes sit with the heaters on for three days before he starts to use them.

 

[Flisker]

So I'm just testing Euphoria for a first time and I noticed that cathode on one of the driver tubes seems to glow significantly more than the other.

Is it just because one tube might have filament pushed more to the edge up there, so it seems like it's glowing more ? Or is it possible issue with the tube ? I noticed this on some other different tubes in past but didn't pay much attention to it.

 

[mordy]

So I'm just testing Euphoria for a first time and I noticed that cathode on one of the driver tubes seems to glow significantly more than the other.

Is it just because one tube might have filament pushed more to the edge up there, so it seems like it's glowing more ? Or is it possible issue with the tube ? I noticed this on some other different tubes in past but didn't pay much attention to it.

It means nothing - you are right in that the assembly is a little different or in a different position in the tube.
Nothing to worry about at all...
Very often tubes made on the same assembly line, even the same day, differ a little. It is almost a rule that they heat up to slightly different temperatures as well. A tolerance of 10% was considered perfectly acceptable in the tube era.
Just think about it - a voltage difference in driving a 6.3V tube between 5.67V to 6.93V is just fine.
Hope I don't offend anybody with these statements, but they were verified by a friend of mine who is an audio-visual engineer and worked as such in the tube era some 60 years ago.

 

[Flisker]

It means nothing - you are right in that the assembly is a little different or in a different position in the tube.
Nothing to worry about at all...

Perfect, thank you! Tubes have probably 300 hours on them and play perfectly fine, I was just curious.

 

[mordy]

Perfect, thank you! Tubes have probably 300 hours on them and play perfectly fine, I was just curious.

Sometimes one tube glows brightly and the glow in the other one is barely discernable...