Amp break in?

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MadAsAHatter

MadAsAHatter

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This has come up in the IIC+ thread and I thought it may need it's own discussion.
I've heard of speaker break in and tube burn in, but never once in my 30 years of playing have I heard someone say anything about amp break in. I know as components age and break down it can change the sound of an amp, tough that takes place over decades. The closest I've heard to amp break in is people say "give the amp time it may grow on you". Though I don't think that has the same implication as a break in period.

From the IIC+ thread, several people are talking like amp break in would be common knowledge. I've also seen many threads about not liking an amp out the box, but never once seen anyone mention in them to give the amp time to break in it'll sound better then. I'm not trying to say it is not a thing, just that I haven't heard of it. I also have no frame of reference because 99% of amps I have were bought preowned. So if there was a break in period I wouldn't have experienced it.

So what's up with amp break in?
How long does it generally take? Are there certain components that need more time to break in than others or is it specific components (like filter caps) that need a break in period? Does the break in change the sound, the feel, or both? Is there anything that can be done to speed the process?
 
Interesting, i'm not sure I have an opinion either way about this
 
i questioned all this in that thread, as somehow it was my first time hearing about what seems to be common knowledge for everyone else as well :dunno: if its 50 hours playing time like i saw mentioned, i only have a few amps that are actually broken in be it they are new or have new caps and whatever, and if i actually do have that amount of time on them, i did not notice the big change much like i never notice the big change in speakers many say to hear as well. maybe my ears just suck and i dont know shit about fuck, which is a strong possibility.
 
is this amp break in always a good thing?? it always seems assumed that speakers sound better over time, which i kind of question as whats better for one isnt always good for another.. what if the amp mellows out, loses tightness and punchy and starts feeling dumpy?
 
This is what Alan from Carol-Ann had to say about it:

First and foremost, I'm an Engineer and don't do mojo BS. The fact this Industry has become a marketing nightmare of BS and lies not only misleads people, but attempts to fill knowledge blanks with marketing instead of fact. Add to that a billion unqualified people on the internet all with an opinion. If I can't measure it or analyze it, it ain't happening. Emotive response based on gut feeling is completely unreliable when attempting to address something like this subject. Often what sounds 'better' is simply a result of you playing in a way you perceive as 'better' so something external to you must have changed, right ?
So for this discussion, while its impossible to completely remove ones own tonal preference, the end result should be thought of as reliable unit operating within its design parameters.

However........
Yes, I can certainly vouch for the fact that amps do break in. They start off a long way from their intended operating points. Its a rather exponential process. No newly built amps sound incredible on first fire up, I've built a few thousand so can say this with a lot of confidence. Almost every component 'breaks in' to some degree or other. For some components, its not so much a break in, more a settling at a particular operating point or range. Tubes certainly do initially burn off contaminants on the cathode coating and on other structures, even contaminants in the gas itself (every fired a brand new power tube and heard some crackling that goes away after several minutes or an hour or two) . It also takes a little while before their bias will remain stable. Preamp tubes as well as power tubes. Electrolytic capacitors form an oxide layer on the plates over time. There's a period of about 30 mins to 2 hours where you can see the ripple levels change on a scope as they start to operate more efficiently. Their ESR also decreases in the same time period. The electrical and magnetic properties of transformers change too, but that's more long term. This process continues, eventually flat lines and then starts to reverse as some component starts to reach the end of its working life, usually power tubes are the first to degrade.

The break in testing is as much to insure against premature failure as it is to 'make the amp sound and feel right'. However, there is a marked change between hours 0 and 1 and hours 1 and 5, the noticeability of the change gets less and less after longer periods of time. Noise levels do also generally decrease, but not always, they can in fact increase in some cases.
I wont even start to tweak or change anything once I've got an amp up and running properly, until its been hot run for a couple of hours. Its pointless as any change you make is countered by all the other parts settling in to their operating environment.

Speakers are an electro-mechanical device, so they certainly break in. Some people use variacs to attempt to speed this process up. Personally I think you are better just giving them the complete signal range by simply playing through them in the way you intend to use them and putting up with about 20 hours of stiffness.

Outside of this, the most major factor to changing tone on a day to day basis are changes in wall voltages, temperature and humidity. All these factors affect the operating points due to resistive, capacitive and inductive changes and the fact that every component has a tolerance band. I developed the autobias system to counter some of the major factors that change the tone of your rig from club to club due to bias shift caused by changing voltages.

Just a word of warning on buying 'burned in' tubes. If by burn in they mean fired up with the filaments heated for 48 hours, that's not really doing anything apart from creating a nice orange glow and giving them an excuse to take an extra $5 from you. To settle in a tube (for me) has to be done in its end operating environment. Granted, a few hours under load by the Supplier on a test rig will certainly help find early failures, but they will still need to 'settle in' in your amp.

So, its all very real and physics can 100% back it up. Now heres the big caveat that separates science from Mojo.....BREAK IN DOESN'T ALWAYS GO IN A POSITIVE OR PLEASING DIRECTION. Think about it, that would be impossible. You certainly can get an amp that sounds great after two hours and by hour five has settled in to a less than ideal place and requires reworking. This is the reason I gig test every amp. Some things I may only notice when its being used in a live setting. However, the general direction of the settling in period usually leads to a more stable place and closer to the actual intended design points. Hope that helps.
 
So the boutique builders tweaking away on the internals endlessly; then finding the sweet spot…. “Bam don’t touch it, he says to himself….“. Fifty hours later, at @rtmember house… this amp sucks.
I always thought break in period was for moving parts like a car, a speaker, a turbine. Maybe a bit of goop has not fully settled in, or a little grease not burned, extra heat baking in the electronic goodness. Interesting for sure.
 
It makes sense that new components in an amp will change with some use and "settle down"; some eventually will start to wear-out and go below their intended operation and need to be replaced.

I would guess most new amps are getting some level of QC, including running the amp for some time to be sure no components fail as mentioned above.

What isn't clear is how much time to go from new to "settled down", and can you hear a noticeable difference? Then how much difference is due to the amp vs the speakers breaking in (e.g., if you get a brand new amp and new cab at the same time)?

If a new amp sounds good when I buy it, I expect it to sound good until parts wear out and need to be replaced, and once replaced to sound good again.
 
It's real.

I had the cathode bypass resistors changed on one of my Twins. Amp was so sterile and harsh afterwards that I took it back to the tech who played with a few values while I sat there and tried it. Nothing changed. Sterile, harsh, like a solid state amp. He finally told me "you just gotta play the amp" and put the original value back in. So I took it to my gig and it was sterile and harsh sounding. Overly bright and overly tight. Can't dial it out. By about midway through the 2nd show it opened up and sounded awesome again. I think it was about 3-5 hours of playtime, somewhere around there, to get it back to normal. I was thankful, because it was unusable otherwise.
 
I believe it is real. It makes sense to me. I believe the edges will soften a bit with some use. Ive had the same experience with new guitars as well. They break in as well.
 
I don’t know if it needs a break in or not. But it does seem strange that hi end amps are adjusted and tuned, then shipped but then need to be broken in.
 
I can only say that anecdotally every new amp I’ve purchased (which hasn’t been a ton as I normally buy used) has sounded “new” - crisp, strong, and tight. Every old amp I’ve owned has sounded “old” to some degree or another- warmer and saggier and less strident.

It’s a damn shame we don’t have a future Time Machine to put this to the test. Then again, you wouldn’t be able to come back and tell everyone your results so it doesn’t matter
 
Breaking in an amp for me was always playing it really loud until is sounded right. It usually takes a few hours.

I even practice this method when I buy used amps. Fuck, I'm still trying to break in my Block Letter 5150. I can never seem to get it loud enough without cops getting involved.
 
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