Simple question, probably stupid

Is it necessary to have sound (music or white noise) playing through the speakers when burning in new tubes? I have bought a matched quad of Shuguang KT88 Z Black Treasure tubes to compare with my current Gold Lion KT88 and Tung-Sol KT120 tubes in a Rogue Stereo 90 amp. Reviews of the Shuguang tubes indicate that they need around 200 hours of burn in to reach their true potential but I am not looking forward to having to listen to 200 hours of crap sound.


Why burn in tubes and waste hundreds of hours of tube life?  Regardless of whether you believe burn in improves sound, the amp should be enjoyable and usable right from the start.  If a tube amp doesn’t sound good within five minutes, even with brand new tubes, something is wrong.

     This is a verbatim quote, from a letter Brent Jessee sends, whenever one buys valves from him:

     New tubes need a break-in period before they can fully exhibit their true sonic character when used in audio circuits.

     Preamp tubes especially benefit from a good break-in. This period may vary widely, but NOS vintage tubes usually need at least 48 hours of use, sometimes up to 100 hours.

     New current production tubes need 24-48 hours typically.

     Good break-in can be accomplished by either leaving your tube unit turned on in a no-signal condition for 2 days, or you can just enjoy the tubes for several hours each evening and they will be broken in after several weeks.

     New tubes, especially NOS vintage tubes, may sound a bit edgy at first, but after the break-in period will mellow out and sound wonderful."

Good question, not stupid at all

on, no signal needed, 60 hrs

brent jesse

advises burning new tubes in for 60 hours, before listening, then judge how they sound.


my last order, I had working tubes (unmatched, but wanted a new matched pair of 6sn7’s that did not look absolutely identical to my adjacent 6sl7 (I had blown one I somehow put in the wrong socket position after testing them).

Received the new tubes, compared to existing some magic was gone, burnt in 60 hrs, still didn’t like them, returned.

bought a matched set that cost less, full credit, and refund for the price difference balance due. I paid shipping to return them of course.

Magic returned!

That’s the reason I recommend buying from Brent.



Good question.


I have found the majority of tube burn in happens very quickly… about 10 hours. Then the amount of change is vastly smaller.


I would get the first ten hours on them. Then enjoy listening. However, obviously if they sound too edgy and not enjoyable… burn in until they do.


While you are at it while listening, see if you hear a lot of change. I’d love to hear your observations along the way.

Your question is more an example of too much information on the internet.

"Broken in " tubes are just an enhancement(if at all)to an already good piece of equipment.

Enjoy your new amp and limit audio forum time. 

+1 @larryi Just inset your tubes press play and enjoy the sound steadily improving.

Thank you to all those who read, understood and responded to my simple question and to all those who chose to answer a completely different question ie do tubes need to be burnt in? With regard to that latter issue, as it has been raised, I might as well add my 2 cents worth. If Brent Jesse, a guy who has extensive experience with almost all types and brands of tubes, says they need burn in then in my view they need burn in. If anyone on this site claims they have more experience than Brent Jesse please raise your hand. Also why would all reviewers of the Shuguang tube, who generally responded favourably, make a point that they need an extremely long burn in time? In my experience over many years (too many years ) I have found that some tubes need about 10 hours burn in and others much longer. I have never encountered a tube that needs 200 hours so when I start to use the Black Treasures I guess I will find out.

The point we are trying to make is—burn them in by enjoying them.  They should not sound horrible in the process.  It will also add to your knowledge if you listen to the process instead of just using the tubes as room heaters.  

With new tubes from China, Russia 50 hours is pretty close to runin 

and not anywhere close to NOS tubes which take 2 x to settle in any last much longer the tube standards were far better ,such as 98+ % vacuum 

vs 92-94% today , the metal recipe quality is not there back in the 50-60s grids many times inspected every 100 pcs now many every 3000.

the new Gold lions they bough5 the name ,not even close to the originals.

Tungsol made the Best 6550- today called kt88, even GE  much better 

or Japanese made from the 70s. That’s why I only buy or have custom built 

by RaduTarta  SET or transformer ,choke coupled preamplifier ,for quality throughout no China or Russian Anything. Emission labs makes nice tubes 

as well as Western Electric 300B orTaks from Japan.

I suspect they’ll sound great fresh out of the box…with potential to improve even further from there with time.

Admittedly I’m a bit of a burn-in skeptic anyway. It’s a very convenient way to minimize returns. I won’t mention the brand but was told a firmware update requires 300 hours of burn in.

I listen to tubes I roll as they burn in, and here's what I've noticed in my system: Power tubes and rectifiers 25 to 50 hours, signal tubes 50 or more....all of my signal tubes are mostly 50s and 60s NOS. They all sound good out of the box, but I won't listen critically until about 50 hours

Hello mazian.  It is important not to operate a tube amp using output transformers without a load on the output terminals. (As opposed to solid state amps which don't care about having speakers connected.) The advice of others responding before me is quite useful. So if you decide to play music while putting hours on the tubes (not really necessary, as they won't sound "bad") substitute a suitable resistor for the speakers if you don't wish to hear whatever is playing.  I encourage to play your favorite tunes and enjoy the music.

Tubes don't burn in but your hearing gets accustomed to the music and tricks your brain into believing there have been changes. Interestingly, literally every example that I've read of something "burning in" has resulted in better sound. How could that be?

Mho, there are no stupid questions, really.
Inspired to inane answers, yes. 

I've viewed 'break-in' as something that should be done with ss as well; 'conditioning' to a life of service...

I recall when for vehicles of any sort called for a break-in period of +/- miles before one did 'pedal to the metal', to let all the mechanicals 'seat 'n seal' properly.

How about a 'structured approach'?

10 hr. 'idle'; on with no signal....just warming up.
10 of white or pink noise, low volume.
10 of low volume program, 10 of louder, etc.

That allows for some degree of 'grats', even if not 'immediate'.... ;)

Can't hurt, might do the thing that's suggested without having to 'pause the Cause' for 100... ;)

Enjoy the 'arrival', J

I have always found that tubes do get better with "burn in time". As others have said and as Brent Jesse who is my go to for NOS tubes says you have 2 options: leave the amps on for the desired period of time, no signal needed or just burn them in by using them. I've generally done the latter as I really enjoy hearing how they change. 

I guess I’m lucky. I’ve never had tubes sound bad right out of box. Having said that, some tubes get better in a few hour.  It’s not hearing bias or my ears adjusting.  I usually by an extra set when buying tubes,( just in case ) and have A/B them after a few hours and they do sound better.

All the best.