Burn in electronic components


#1

Hi all,

I am curious as there is much debate about this on other forums.
I have a 2 channel tube mic pre. I rolled the op amps, film caps and tubes.
There are some that say to “burn in” with white noise for a good 24-48 or more hours…others say it’s a myth.

I would welcome all qualified responses and experiences.

Thanks


#3

Here is an article I trust:
https://tubedepot.com/the-benefits-of-burn-in-power-tubes

I would recommend burning in to get rid of contaminates that have naturally accumulated during the manufacturing process.

Side Notes:
Burning in is a good way to determine any manufacturer defected tubes before installing them and “selling the amp” like a manufacturer does -along with the added benefit of the amp sounding great “out of the box” and potentially longer since the oxides are evaporated which won’t happen by using the normal heater voltages. Although more stable after burned in, they can also adjust the circuit gain or “calibrate” the tube(s) at factory since every tube gain wont be exactly the same.

In general, you “wouldn’t have to” and you could run them how you normally would any tube amp which would be to allow them to warm up for a few minutes before using the amp for best sound. Burn in hours does of course take equivalent or slightly higher life hours off of the tube since they are on, and slightly higher voltages than normal.


#4

Hi Ryan,

Thanks for your reply. I am not an engineer but did take physics 301 and I understand much of what my subsequent (much) research garnered. I hope this may benefit others…I have used Tube Depot before but got the last 2 GE 6072A from Brent Jesse, a well known tube Guru.

He states that at least 48 hours of burn-in is necessary for a tube, especially if it is NOS, as the gas and resultant deposits need to settle, having to due with emmisivity…even resultant vacuum inside the tube.

I think most laymen confuse “burn in” with “warm up”…

Also, interesting enough, I spoke with David Geren at Cinemag transformers, whose company designs and builds audiophile transformers. I have 1 each channel in the mic pre mod. He (and his audiophile clients) have found that also with transformers there is an easily perceived aural difference after burning in a transformer with white noise signal, especially those with higher turn ratios and impedance.

Brent Jesse states that, unlike transformer burn in with a signal, tubes just need the “heat” to change the chemical structures inside the tube.

I hope this helps. I have found that there are very different two sides to this subject…radically opposed. I prefer to research and then trust my ears to the results. I am doing A/B experiment with sound recordings…If you’re interested in the results, let me know…

Disclaimer: I have questioned the above named for years in pursuit of their products and found them superior, but I am …just a picky end user. I neither am employed by them, nor a representative of them.

Best Regards,

Christian


#5

Thanks Deccakid, very interesting information indeed. I think you are on the right track.


#6

Hi Kaleb,

Thanks for your reply…Yes, after fairly exhaustive research from even more sources I do believe I’m on the right track!!

I have found much more educated info that supports this. Brent Jesse further that 48 hours minimum is necessary but could be up to 100 hours for NOS tubes. 24-48 hours for current made tubes. A lot of info I got, mostly scientific but I do believe they are correct and makes perfect sense.

I do believe that the unit and application is so important. Many people who roll tubes are guitar players…a whole different beast!! I also spoke to a guitar amp Guru who mentioned that in a guitar amp one would hear differences, but in a mic pre they would be MUCH more pronounced.

Also, we talked about pre-amp tubes vs. power tubes…pre-amp tubes do not need biasing, power tubes do…even suggested in power amp tubes that bias must be checked as can float over time. Does that not suggest that things are happening inside the tubes???

The issue is that it is difficult even for top audiophile to scientifically measure these changes, but it is conceded by all with whom I spoke that this phenomena can be perceived aurally.

'Hope this helps all who are of interest.

Christian