Amplifier burn in time

[audio bill]

Speakers with passive crossovers have electronic components that benefit from break-in besides the drivers' mechanical characteristics. Many speaker manufacturers recommend 100 (or even a few hundred!) hours of break-in until they will sound their best. I don't care to get in an argument about the validity of this, just passing along what I've heard over the years. Please don't shoot the messenger!

[GaryProtein]

How could anybody design a crossover if it took over 100 hours to see if a design change was any good?

[jdandy]

Originally Posted by audio bill

Speakers with passive crossovers have electronic components that benefit from break-in besides the drivers' mechanical characteristics. Many speaker manufacturers recommend 100 (or even a few hundred!) hours of break-in until they will sound their best. I don't care to get in an argument about the validity of this, just passing along what I've heard over the years. Please don't shoot the messenger!

Bill.......Agreed. Crossovers are an extension of the amplifier's output circuits. It is these hard parts, particularly capacitors, that will need break-in time, in my opinion.

This is the beautifully robust crossover inside a PMC EB1i speaker like my pair in the living room system.

[jdandy]

Getting back to the original topic of amplifier break-in, it has been years since I purchased the pair of MC501's that I owned. Thinking back, I don't remember having any lengthy break-in period with them. If memory serves me right, the MC501's sounded smooth and musical from day one. It is interesting to me that my MC601's performed likewise, but the two stereo amps (MC352 and MC452) took their merry time settling into their permanent voices. I don't know why this would be but it certainly was the case for me.

[PHC1]

Originally Posted by jdandy

Getting back to the original topic of amplifier break-in, it has been years since I purchased the pair of MC501's that I owned. Thinking back, I don't remember having any lengthy break-in period with them. If memory serves me right, the MC501's sounded smooth and musical from day one. It is interesting to me that my MC601's performed likewise, but the two stereo amps (MC352 and MC452) took their merry time settling into their permanent voices. I don't know why this would be but it certainly was the case for me.

Going from memory, the biggest changes occurred around the 80-100 hr mark on my pair of 501s years back. The sound started to open up and finally started venturing out beyond the speaker's "womb" to fill the soundstage out nicely. The sound also took on much more organic and musical character instead of sounding mechanical and uninvolving.

[jdandy]

Originally Posted by GaryProtein

How could anybody design a crossover if it took over 100 hours to see if a design change was any good?

Gary.......In a manufacturing environment a 100 hour testing period during a designing process is not a serious constraint. Many manufacturers tweak individual parts in a design, then put them through extensive measurements and listening tests. Prototypes and adjustments to them can take quite some time to arrive at the final parts configuration. This is not uncommon.

I remember reading an interview with Mark Levinson where he discussed how he and his design team voiced their amplifiers. They would literally sit and listen to a pair of mono blocks, decide to change a capacitor value or a resistor value, make the changes on the spot, then audition the change for the next few days. Levinson said in the interview that this process often continued for weeks at a time or longer until he and his team were satisfied with the amplifier's voicing. Then and only then would the amplifier go into production.

I suspect there is a lot more time being invested in circuit designs for high-end audio gear than we realize as consumers. Heck, Bryston burned in my 10B Sub active crossover for 100 hours at the factory before packing and shipping it to me. Obviously they consider break-in to have merit. So it is with me as well.

[aardvarkbark]

Originally Posted by Venere

Thanks for the responses. My experience over the first few days mirrors JDandy's comments. Hard to listen too. Almost too much in your face detail. A bit of an edge to the midtange. Not too happy so far. Hoping that things get better with more hours on the amp over the next few days. We shall see.

Possibly a call to your dealer and email to the manufacturer are in order? They should be able to tell you what to expect for your specific amp. Ayre says 'up to 500 hrs' to achieve full break in on theirs. I do read in many forum posts that almost everyone experiences 'mechanical' and 'synthetic' sonics out of the box, but that then the sound becomes 'richer', 'warmer', 'organic' (still trying to figure out what this means), 'deeper' and 'wider'. Seems like you may be on that path.

Almost every reviewer in the magazines talks about letting test units run a few days before coming back to do their critical listening, too, so there must be validity to it.

What I'm now learning (and should have known) is that an amp, even fully broken in, might not produce the preferred or expected sound if it wasn't auditioned with the speakers in use (system synergy) or at all (a review may be wonderful, but you just can't hear a review).

[Venere]

Originally Posted by aardvarkbark

Possibly a call to your dealer and email to the manufacturer are in order? They should be able to tell you what to expect for your specific amp. Ayre says 'up to 500 hrs' to achieve full break in on theirs. I do read in many forum posts that almost everyone experiences 'mechanical' and 'synthetic' sonics out of the box, but that then the sound becomes 'richer', 'warmer', 'organic' (still trying to figure out what this means), 'deeper' and 'wider'. Seems like you may be on that path. Almost every reviewer in the magazines talks about letting test units run a few days before coming back to do their critical listening, too, so there must be validity to it. What I'm now learning (and should have known) is that an amp, even fully broken in, might not produce the preferred or expected sound if it wasn't auditioned with the speakers in use (system synergy) or at all (a review may be wonderful, but you just can't hear a review).

good advice and exactly what happened. Dealer told me to give it a few days of listening, which I did, and the harsh sound I heard out of the box is gone. All the descriptions you used for the sound are valid for the before and after process. Probably took about 20 listening hours to normalize. If it continues to improve over hundreds of hours I will be quite happy.

[kingm88]

Originally Posted by Venere

What is general opinion on how long it should take for a brand new amplifier to sound its best? Is burn in time even a real consideration or do amps sound their best even when new? Lastly, if you have gone through this experience please describe the sound of new vs burned in amps. I just got new amp and curious if the sound is likely to change or if what i hear now is the final product. Only about 10 hours on it so far. Thanks for the feedback ( pardon the pun) guys.

From my experience it can take a few hundred hours for the amp to settle and sound its best.
I have a ARC DSI200 amp and I have been running it over the last few months. Initially the sound was congested, lack bass and sounded flat. The sound was good but lacked air and the soundstage lacked any real depth.
After a few hundred hours the amp is starting to open up and the soundstage has width and depth with the midrange filling the space.
Arc recommends 600 hrs but that would depend on your amp.
I think that if you have a source that has a variable output you can set it on a lower output so you can turn the volume higher on the amp and that will speed up the process.
But it really does require a lot of patience but you will know when the sound changes.

[Rex Anderson]

I just read Bryston has a burn in procedure to test their amps before they ship. I believe it was 100 hours and some sort of cycle.

Maybe not all amp manufacturers follow that procedure.

I also read somewhere that Kevin Voecks of Revel says loudspeakers don't need burn in time.

Found it!

"Bryston takes great pride in the quality, reliability and durability of their products, backing them up with an industry leading 20-year transferable parts & labour warranty on all analog products and 5-years on digital products. When it comes to their amplifiers, Bryston subjects them to extreme stress testing at their burn-in station. All amplifiers, once assembled spend a minimum of 100 hours being cycled on for 1 hr and off for 1 hr. During the on cycle, they are fed a square wave input signal that runs them to their maximum output. 100 hours on this bench is equivalent to about a year of normal use. It’s like a boot camp for amps that they must pass to get their badge of health."