tube suggestions/ brand new to tubes

Brent Jesse, well respected, just sold his business told me: leave the unit on, no content needed, for 60 hours, tubes break-in done.

After that, listen.

@signaforce , @larryi , @jjss49  

First, I would like everyone for their advice and suggestions. After listening to you all, I realized,  HOW much I don't know!!!!  The best advice from all is to listen for that maybe 100 hours,  to see the flavor that your listening to.

Upon first listening, my SVS SB 3000 was dialed in perfectly, and the sound from the Guarneri's was just right. SVS set at -10db (if that's is saying it correctly) had to really push the sub in the system to get the right BASS. 

As soon as I hooked up the Jackpot, with the same sub setting, it was really terrible, BASS HEAVY,  CRAZY. WOW, was I shocked, and not in a good way. I laughed and said to my wife, What did I do? She said calm down and adjust you SUB. I almost spilled my Buffalo Trace, which really would have been  tragic. Taking the wife's advice, I had to go all the way to -20db for the sub to be dialed in, I was amazed. However, after listening to Audirvana 24/192 Stairway to Heaven, and Metallica, Nothing Else Matters, I was PLEASANTLY surprised. The bass was far more detailed, and deep,and accurate,  the clarity of the Mid Range, voices, instruments was very evident. My impression changed immediately.  

After reading signaforce, larri, and jjss49's post., I am really focused on more detailed and dynamic presentation, as you all said my system is generally considered warm.  I will listen for a few hours this afternoon, if time permits. It seems from what I'm able to discern,  I would prefer that more detailed, dynamic sound,  which from what I can gather would push me toward Telefunken or Maybe Amperex (Bugle boy was suggested). I'm going to start looking later this week for a tube or 2 as a back up, should something happen prematurely to my supplied Tung-sol 5751.( input stage)  If any of you have one that you think would fit my musical tastes, please let me know about purchase. Thanks all so much! Robert TN

I will repeat what others have said.  You need at least 50 hours on the tubes and lots of listening times.  I like to listen during breakin at least periodically for the changes. Tubes are a bit like gardening.  It is a slow process to see or hear change.  

I recommend new tubes.  They are making news tubes specifically for audio and honestly, I think they are better than playing the made 50 years ago NOS game.  IMO, new audio tubes made with modern design tools and equipment are more accurate than a tube made 50 years ago for a radar or basic radio.  Tubes already add in tube flavor and many NOS go too far into tube land.  Now if you need or want that go for it, but I prefer the accuracy of new tubes.  For small signal tubes, I have found Rays Reserve and Gold Lion Gold Pin to be the best in the 12AU7 tubes.  Great clarity and still the holographic sound of tubes.  I find 40 to 50 hours is needed to for break in for my ears on my equipment - might get better beyond that, but if so, it would be small and I am on to different upgrades.  Finally, my tube preamp did not like being paired with the Gaia isolation feet - the sound was flat and without sparkle and I lost soundstage.  

@12many raises an excellent point... fresh tubes (of any make) sound so much better than tired tubes with lower mu (transconductance) resulting from use and natural degradation ... tubes certainly do wear down over time in circuit, and the effect is aging tubes is often less treble detail, air/soundstage and visceral impact

this is especially important when buying old stock tubes that are ’pulls’ from antique equipment... think of it as buying used tires off an old car... in the case of tubes you need a proper tube tester to assess, rather than a visual inspection of tread depth etc etc

Best advice I can give is only use exact specification tubes.    Don’t go on someone’s suggestion,  if in doubt find a resource like a late model  Hickok tube tester owners manual,   

There are charts with exact substitutions , like 12ax7 and ecc83.  One is the US name and the other is European. 

There are close substitution charts too but I would only use exact types.  Tubes that gave the same electrical specs like current draw and voltage.    Lots of date that can help make good, safe replacement tubes without risking damage.