Why does it take so many hours to brea in arc preamps and amps?
I recently purchased a like new ARC 5 SE pre amp. The unit had less than 200 hours on it. Everything I have read states that ARC preamps take up to 600 hours to fully break in. Why is this so and what improvements can I expect to hear as the unit accrues hours?
Warm up is fine for correct bias to be reached and dc offsets to stabilize.
From new first power up, a few hours are fine for all caps and components to form.
But 600hrs to reach optimum sonic ability is shear voodoo, and as has been said it's just "expectation bias" or as Nelson Pass calls it " burn-in of the listener"
In the final analysis all we can listen to is manipulated power. But it is manipulated power, be certain of that. Is it even possible to listen to precisely the same signal every time, even if we wanted to? Conversely could we possibly hear marginal differences, even if we wanted to?
"I have yet to hear a tube amp that sounds as good after 5 minutes than it does after 1 hour let alone 4 hours."
agree. Air, bloom and soundstage are MIA until later on, after an hour for sure. This is the sort of thing that apparently separates the mid fi troops from the rest of us.
Its not just ARC equipment. I was told by a modifier who replaces mediocre components with high quality ones, that quite often the best ones take longer to break in. Now, if I could not hear it for myself? I would call it marketing BS. But, what ever it is that takes place to burn in a component? No one has yet to find the science to show what actually takes place. In the mean time, the fact remains that something takes place, and is discernible. I have witnessed to it too many times to doubt is a real phenomena. Its possibly something takes place on the molecular level that no one yet knows how to measure for. When there are electrons, voltage, and current moving through resistors, capacitors, switches... wires, etc? Who knows what changes it causes? Our ears will know its a real phenomena if our system has the resolve and transparency to demonstrate it.
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"I have yet to hear a tube amp that sounds as good after 5 minutes than it does after 1 hour let alone 4 hours."
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I think you are confusing 'warm up time' with the process of 'burning in - breaking in.' Warm up time may take for you 5 minutes and is how long it takes for a component to stabilize after turning on. Burn in time different, and is a transformation that takes place that causes a component to reach its design potential. Its like breaking in a new car engine that can take hundreds of miles. Its not to be confused with how long it takes an engine to warm up before running.
If you think about it, all the optimum adjustments are made at the factory after the amps been on for a while, maybe an hr if your lucky. If thing change after 600hrs then those optimum factory adjustments have just gone out the window and need to be redone again.
So it’s either out of adjustment because of aging, and therefore not optimum, or the factory needs to have them on for 600hrs before they are adjusted and sent out to the shops. Either way if things change they would be out of the original optimum adjustment. "
Cheers George ******************************************************* In response to this, "burn in" and "being out of adjustment" are not the same. When a unit reaches burn in doesn't make it out of adjustment and requiring new setup from a technician. The components may be aging but this is a good thing. Everything reaches its optimal state of age and for most electronics it takes a long time to consider them not good. Generally I think under 100 hours is the most you should expect to break in a large variety of components. The amount of "current" can play a role as well.
In fact how a unit sounds after break in is a planned part of prototyping to final design. All electrical parameters are set to reach this "break in sound".
During break in an electrical effect happens, the flow of the electrons across all of the components causes micro surface arcing and tends to smooth and create a shortest route pathway. There is also a small magnetic field that develops around all paths which affects signal flow and interaction between materials.
To give you a visual idea, all this happens over time like water flowing through a pipe that had very fine sand in it. The effect smooths and polishes the edges and surface of the pipe, to electrons at an atomic level it also aids in flow. The flow of electrons can be a violent one, if they "carve" themselves the optimal pathway noise decreases and more of the original signal is heard.
In response to this, "burn in" and "being out of adjustment" are not the same.
If you know better convince Nelson Pass of this below, in case you missed it.
Nelson Pass:
"We burn products in for two reasons -
1. We want to see if anything fails.
2. We want to readjust the amplifier against any drift in performance that comes with a burn-in."
Nelson Pass on "Burn In" "It's pretty clear that any such long term behavior is going to be obscured by the burn-in of the listener. People come to new audio components carrying the experience of the previous equipment, and may experience some dissonance with the new sonic character, even if they like it overall. Over time they often get used to it and grow to like it. There are plenty of cases where they initially like it, but the sound becomes irritating over time. That is called burn-out."
Yes of course these are factors in any piece of gear, but where do most manufacturers draw the line? Nelson Pass is an exceptional designer of both consumer and professional gear, but this isn't explaining what burn in is?
He is also doing this because he knows that on occasion a small percentage of parts "drift" from their values quickly and are by their standard out of spec, not necessarily anyone elses spec.
I have built and repaired many pieces of gear and always take readings of the values of for example capacitors and resistors, they can be so close to spec for dozens or even hundreds in a row and then all of the sudden so far from spec. This is why all good manufacturers burn in their products and do a final analysis of specs. They know from experience the parts failure, drift and burn in time rate that is expected.
Quoting Nelson Pass doesn't make your description any more accurate than you previously stated, that is his procedure for meticulous production standards which are seldomly done by any in the field because final costs of products get pretty high.
Nelson has set the bar pretty high for himself and can't be caught with his pants down so going to those lengths of "burn in" is beyond what is burn in. It really making sure his product has satisfied his standards to not get back a piece of gear for component failure within the warranty period or even much longer. This is so far above most others ethically alone that it is a personal over financial gain that few choose to go to.
Think about what "burn in" really is again in the real world in everyday use products.
I think the notion, differences and understanding of "burn in" are pretty misunderstood form reading many descriptions.
If everyone realised that "burn in" has so many factors involved that it should be broken into sub categories of "break in" rather than "burn in", perhaps getting a better idea of what is expected from it might be easier to answer?
I know when I buy a new piece of gear or replace a capacitor I call it "break in". A new piece of gear that has been used for some time is "broken in" but also well "burned in".
A new piece of gear that has been broken in and burned in for some time and needs say a few new capacitors because of failure is still burned in but needs to be re-burned in again because the new capacitors will take about anywhere from 10-100 hours to break in and reach their final burned in sound. The gear as a whole is still burned in just the capacitors will keep changing sound until they get to a certain point. Break in generally refers to getting a part or gear to certain point of aged reliability through a controlled break in of parts. Not all parts can go to 100 percent full on from new and have to be slowly broke in or premature damage could result from over heating or sudden stress. Metallic parts are heat treatable so too fast of or hard of break in can actually change the way a part ages or takes to being able to predictably get past the final "burned in" point.
There is a point where different electrical parts take longer than others to get to their "optimal state" from new. And then from that point they are degrading slowly and steadily. The sound may change for better or for worse. It is a combination of experience and parts that dictate this.
One good example of this is Cables. A cable only has the variables of the wire and dielectric. A little more straight forward from a "burn in" point of view.
Most speaker, power, interconnect, etc... are not "broken in" because they have a near zero failure rate, have no electrical parts and ultra high consistency in sound out of the box. They are just used to transfer electricity or the source signal. So here we can refer to where I believe many confuse the two, "break in" and "burn in". They similar but different as the burn in is only really changing the surface and magnetic field of the wire and dielectric. So because these attributes change the the conductor so does the sound for the reasons I stated in the original post I made.
So hopefully this makes as much sense to you as it does to me? ;)
In response to this, "burn in" and "being out of adjustment" are not the same.
If you know better convince Nelson Pass of this below, in case you missed it.
Nelson Pass:
"We burn products in for two reasons -
1. We want to see if anything fails.
2. We want to readjust the amplifier against any drift in performance that comes with a burn-in."
Nelson Pass on "Burn In" "It’s pretty clear that any such long term behavior is going to be obscured by the burn-in of the listener. People come to new audio components carrying the experience of the previous equipment, and may experience some dissonance with the new sonic character, even if they like it overall. Over time they often get used to it and grow to like it. There are plenty of cases where they initially like it, but the sound becomes irritating over time. That is called burn-out."
Classic case of Appeal to Authority. I.e., just because someone deemed to be an authority offers an opinion on something doesn’t necessarily mean it’s true. One actually doesn’t have to look too far to find a designer of audiophile amplifiers or whatever who has stated he has some sort of issue with break-in/burn-in of amplifiers, cables, capacitors, wiring, fuses, wire/fuse/cable directionality, polarity, or anything else related to audio. In fact, if I may be so bold, amplifier designers might be the most dogmatic of the bunch. No offense to Mr. Pass or anyone else.
It's the massive teflon capacitors that need the break-in time. I have a ARC Ref 10 preamp and I know it can be an agonizing process to wait for the full blume and potential, but as others have said its well worth the wait. I can honestly say, having listened to and owned many other preamps, the ARC Ref 10 is the best I've heard (after 600 - 650 hrs of break-in). It's within a hair of the VAC Statement that costs over twice as much as the Ref 10. Hang in there your patinece will be rewarded. Ray
Exactly! That’s why it’s an illogical argument. An argument cannot be won by simply claiming to be an expert in the field. Besides, amplifier designers disagree on many things. I'm quite sure I can come up with another terrific amp designer who disagree with Pass.
Make two reasonable assumptions. That there is some of legitimacy to the notion of "getting accustomed to the sound" burn in. There is probably an element of the circuit undergoing real physical changes "during/over use" time as well. Thus there is perceived 'burn in.' QED.... EOD......
Who do you think you are insulting members? Like you own the forum, or are vastly superior in intelligence than the rest of the members? Make a positive, beneficial comment or dont at all if you just want bash people.
Actually, an expert in court provides expert opinion or evidence, not proof. See the difference? Besides an expert can be wrong, his testimony doesn’t guarantee success for whomever he is testifying. And experts don’t always agree. That’s why the defense expert witness often disagrees with the plaintiff expert witness. Hel-loo! That’s why the Appeal to Authority is an illogical argument.
No one can deny that Nelson Pass is an expert, and the experiments prove him right.
Or are you a science denier?
Authority is not as good as an on point experiment but a LOT better than an ill informed opinion? If you don't believe that then do your own surgeries and find out.
I have lots of practical and theoretical, working in the Aviation world in avionics, I also am a certified Machinist and fabricator. I have rebuilt and restored many audio units, reel to reel recorders, tape cassette, amps, preamps, etc... Designed my own gear, built many varieties of cables and so forth. But you may have known that if you actually read the post rather than breeze through and develop your usual assumptions and then criticize others. For those of you who cant build their own gear, the lack of real experience tends to make you more prone to believing whatever sounds most convincing or has been kicked around in forums here and there. You can speak with the moderator about your comments, they know about them and so do you. Have some respect and manners speaking to members.
you're telling me that sophisticated measuring equipment wouldnt show a change to demonstrate what you are describing as bloom or whatever audiophile terminology you want to use?
I do believe this is possible, but not common. It needs time domain measurements, patience and LOTS of data.
Audio measurements are too often really simple things. Steady state sine waves, sweeps, square waves. There are a lot of tests which go ignored or under used. I'm not saying I have proof, but I am saying I think a good data scientist/engineer could eventually discover.
For instance, in speakers, dynamic range/compression is rarely tested by magazines, but it's one measurement I find describes a great deal of what I hear. Perhaps some day I'll come up with cap sound measurements and they'll name it after me. :D :D
But proof, no. Experience, somewhat. I'm not really interested in forcing the issue on anyone though. A skeptical open mind is always a good thing.
anybody can read a textbook on cognitive psychology too (well, ok not everybody...)
I agree it would be hard to measure a change - tho one could arrange a blind listening test to show an effect w/o knowing any mechanistic reason for the effect but... if ARC says to do something, why not do it?
for my ARC pre-amp it warms up for about 40 seconds - could be tube protection tho, not SQ
Having two ARC pre in two different systems, one bought new (17es) and one bought used (LS 27) but with only 200 hours on it when I received it, both with factory papers and both showed a recommended 600 hour break-in.
While the LS 17 does not have a hour counter, it is well over two years now so I would venture that is is well over the 600, and as noted by others, the pre started to open up becoming more defined as the hours mounted. The 27 has just started to increase soundstage (everything else remaining constant) and a slightly annoying high end has smoothed out.
I understand some of the theory, superstition and black magic behind this need for 600 hours, but if we accept the same for interconnects, speaker cables and ac power cables why not tube equipment? I regularly start up everything early in the day and do not attempt to listen until much later allowing everything to settle in producing background music as I go about my day. I have never been dissapointed at the end of the day when I really want to listen to some music...just my .02
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