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How do you know when to replace tubes

I recently purchased the Audio research Anniversary reference
The unit has 2600 hours on the tubes.The manual states replace the power supply tubes after 2000 hours.Do you indeed have to replace the tubes even if the sound is good.Another question is tube rolling enhance the sound .As an aside the Audio Research replaced the Einstein Tube pre amp noticeable improvement to the sound ,mainly the lower mid range and bass.
ramy
atmasphere's avatar
atmasphere
7,068 posts
 
A tube tester is always a good way to tell.

In our gear, it tends to move towards a sleepy sound if the tubes are shot.
mapman's avatar
mapman
15,679 posts
 
I am just a moderate tube user these days, but first thing I check for is any audible noise or hiss. Also if anything sounds unusually different in any way, tubes are one of the first suspects. I keep a few spares around so that I can a/b regression test individual tubes at a minimum and replace if not sure.

Noise is easy to identify but other sonic anaomolies not so much. A good quality tube tester like Atmasphere recommended is probably the only way to be sure. Not as common anymore these days, but depending on where you live, in lieu of owning and using a tube tester yourself, there might be shops nearby that keep a tube tester around and might be able to test them for you.
lostbears's avatar
lostbears
479 posts
 
I would replace the two 6550 in the power supply after 2000 or 2500 hours. It is cheap insurance against the possible damage a blown power tube could do. The 6h30 tubes are not going to do any damage if one fails.

I also have a complete set of backup tubes for all my tube equipment. That way I always have a spare in case of failure.

BTW I own an Audio Research Ref CD7, Ref 110, LS27 and PH8
ramy OP
141 posts
 
I find the comments very useful.I will follow Lostbears recommendation and replace the 6550 in the power supply.
Thanks for all the replies.
knghifi
1,667 posts
 
The only 6H30 tube rolling option I'm aware is 6H30-DR and they are expensive and tough to find plus you need 8.

Caveat Emptor buying 6H30-DR off Ebay located in Russia. I heard many received fakes.

There are rolling options on 6550. Since you only need one, you can try NOS TS, NOS GE ...

I believe your Einstein rolls 6922 so you got lots of options.

My experience is similar to Atmasphere, SQ gets softer as tube ages that will signal time to replace.

According to Kalvin @ARC, all power tubes (KT120 and 6550) regardless of position should be replaced @2000 and 6h30 @4000 hours in my amp so probably same as your pre.

I'm not taking any chances and replace all at the recommended intervals.
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