How do you know when tubes in the phono section of the integrated amp go bad..

Hi -

Those would be 12AX7 tubes.  At the worst, treat it like any other input tube which would be at least 5000 hours.  

No expert here.

Rich 

Yeah. I meant, of course, how to notice a failure if I can't see or hear it without removing them and putting them in the line preamp slot that uses the same tubes. I just don't want to repeat this procedure every other week or so.

Last year I put NOS Brimar military in there so they should be good for a very long time. I didn't like these Brimars, by the way, they had a recessed midrange, nothing like Mullards. High frequencies were good, though.

@inna - 

From the Stereophile review ... 

Inside, all signal paths are kept as short, straight, and direct as possible in relation to the front and back panels, with power tubes and output transformers to the rear, and a centrally located switch in front of the power transformer to choose between ultralinear and triode operation. To the left are four 12AX7 tubes (two for the line stage, two for the moving-magnet/high-output moving-coil phono stage), and on the right are three 12AU7 driver tubes.

So I guess my question would be, if you are not using the phono, are those tubes engaged and does it matter whether they are good or not.  

Rich 

I think, they are somehow engaged, but I don't really remember what Kevin said except that they should be there. He didn't say it didn't matter whether they were good or not.

Checking every week is a bit OCD. 😉 I wouldn’t worry about it. Low power signal tubes last decades. I’ve been using tubes for over 40 years and never had an electronic failure in a small tube.

Maybe he wants the tube there to keep the voltage constant, so as long as the filament lights up it should be fine.

imhififan, right, he did say something about voltage constancy, but I don't understand these things so I can't remember his exact phrase.

Thank you, this is going to be my working solution - if the filament lights up I am good.

In fact, I might put the turntable back in place in couple of years, so I will know even better. But I would have to replace those Brimars with Mullards or maybe RCA or Raytheon blackplates.

You might like the Gold Lyons. Preamp tubes last a long time. You could swap the locations every year. But I think you might notice the difference if a tube went bad.

For these and your other tubes, many can last 10,000 hours, I suggest you get thee a simple tube tester, routinely test them all twice a year, be ready when problems occur to know what’s what.

https://www.ebay.com/itm/226541240161?mkevt=1&mkcid=1&mkrid=711-53200-19255-0&campid=5338381866&toolid=10001&customid=0f75f6f6-eecb-11ef-bfc7-313037316431

Tubes for me began with a huge console I inherited from my Uncle way back in 1973.

Fisher President II made in 1958

Control Center; AM Tuner; FM Tuner; FM Multiplexer added. In the two drawers: Viking 2 Track Stereo Tape Deck (in-line and staggered heads); Garrard Record Changer: Mono converted to Stereo (by Fisher staff who came to my uncle’s apt, Avery Fisher was a friend of my uncle who reviewed Opera for NYT occasionally); Pair of EL37 Mono Amps.

In days of old, twice a year, I would put each component’s tubes in a separate paper bag and go to the local electrical supply store, wait in a short line, use the big professional tube tester,

a big line building behind me: typically find a short or a weak tube, maybe buy one or two.

Come home with pain in my legs and feet, until one day my wife picked me up at the train and took me to a house, told me go to the door, the guy there has something for me. It was my birthday present. My very own Accurate Model 151 tube tester, oh happy day!

Later I got 2 bigger more advanced testers, the little tester always agreed with the big ones which I eventually gave to friends.

I just routinely tested all my preamp and amp’s tubes, all is well.

Oh yeah, my speakers are the President II’s 4 way Electro-Voice drivers/crossovers/level controls, relocated/restored in new Rosewood Enclosures.

Originally, the console was on 8" bronze legs and the 15" woofers fired downward, I made the enclosure taller to fire them forward.

On 3 Wheels allows Alternate Toe-In for One or Two Listeners

This is an easy one.  When a tube goes bad it will talk to you.  That is it will get noisy.  I would describe the sound as a feint spitting sound.  It is annoying, but when it happens, which will happen most likely years from now, you will know it and will have time to buy replacement tubes.  Not a big deal.  It will not hurt anything.

Great Fisher console. Now, that's real vintage.

To get a good tube tester ?..Not a bad idea, maybe.

Yeah, that's one of the advantages of tubes - they usually talk to you, make you aware that something is wrong.

I thought about getting a tube tester, but it’s confusing which one to get for this tube newbie who has never used a tester.

Use the KISS principle.  Your ears will do just fine.