Tube Preamps Should Have This Feature

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How do I know when my tubes need replacing?

Power tubes like EL34's and KT88's are good for about 2500 hours or more. But may go longer in an amplifier with a conservative design. Small signal tubes with numbers like 12AX7, 12AU7, and 6922, and rectifier tubes like 5AR4 may go 10,000 hours. So you get years and years of enjoyment. Using a tube tester may or may not tell you if you need a replacement. The best approach is to buy a new set of tubes, and install them. If they don't sound a lot better, put in the old ones and suck every bit of life out of them.

I am not opposed to tubes, but would like one that I could just leave on all the time that would not burn through a lot of tubes, and also would not heat my house. Are there tube preamps that you can just leave on all the time and expect to get reasonable tube life?

@zlone Linear Tube Audio preamps are excellent and have loooong tube life due to their David Berning ZOTL design, and the tubes are also cheap to replace.  They’re also excellent headphone amps if you swing that way.  Definitely worth a look and plenty of reviews out there that’ll give you more info.  Hope this helps. 

Thanks to all for responses!

zlone

Yesterday, I listened to some favorite music at a friends warmed up tube system with his new to him tube preamp. Sounded great, different and we both think better than before, AND he got remote volume and remote balance, Oh Happy Day. That will make anything sound better!

Came home, warmed my system up, did a few things, listened to same music on my warmed up system. Heard great music and the differences of our systems.

Tomorrow, friend coming, I’m gonna wait till he’s settled, turn the system on, wait 2-3 minutes, play the same music (he is also familiar with that music played on my warmed up system), it should be interesting.

the point is, OP said ’casual listening for short time". It’s the content! A special feature ... no way.

Saving on groceries to buy more tubes is a great idea. What if the man already does it ? And what if his reasons have nothing to do with expenses ?

Don’t know about other amps, in the case of my VAC it s advised to give it at least ten minutes to stabilize before listening and forty five minutes is ideal. But it is integrated amp, with power tubes too. Still I would think at least ten minutes for a preamp.