CD Player - burn in

Or she?

 

try direction flow of molecules in copper, or watch the tide flow in and the sand will form a direction of flow,
nando.

 

what sounds do these make then?

 

bliss, specially in the sunset,
nando.

 

jokes appart, in all the history of my trade, both building and inventing seperating theory with practice, when either cars or any electronic component it does make a difference as the signal creates a flow it does open up, maybe not to your liking or maybe yes, but it is audiable,, and that's why mainly i believe in home trials specially with cables, in theory pending on the purity of the copper conductor it is measured " avarage 80 hours" practiice is a bit more time consuming,
nando.

 

I suspect we are talking about different groups entirely.
I'm thinking of the many thousands of users who buy good kit and just use it without all this faffing, worrying and tweaking.

Existing in the realms of possibility isn't the issue.
I have two plastic coffee cups on my desk at the the moment that look absolutely identical.
They aren't of course. One will weigh a tiny bit more than the other, have fractionally different dimensions to the other etc.
But for the intended purpose and to the end user - they are as identical as they need to be, and differences sit way down bellow what can be perceived.

Same for electronics in most cases.

 

Well funny I was just talking to a friend about this topic today as he's just bought a Moon CD player (and amp and living voice speakers !!) and he asked me if I thought there was anything in this burn in period.......

I had to be honest, I don't know....I've not played my Moon CD player the 400 hours the instructions manual suggests player will improve over......

Because it's subjective.......I could not answer it.....

What I will say though....is he bought the Livingvoice IBX-R2 and I've just ordered the cheaper Auditoriums.....the Auditoriums with the same electronics in the demo sounded significantly better than his brand new IBX-R2's.....and it's not just acoustic differences here......the well used demo Auditoriums sounded in my view excellent....or I'd not have ordered a pair. Based on that I'd think a new hi-fi does need a run in period.....and I would have thought a few hundred hours sounds a long time...but I'm no engineer !

 

good hi-fi any brand you choose, it is just like wine, it gets better with time,
nando.

 

I agree on the point about worrying about burn-in. Why bother, it's going to happen or not with use and it's not a huge difference after the first few power cycles with my experience. Just leave the gear always on and enjoy music.

I have found one exception. I owned a preamp back in the seventies that sounded quite bad after several days of being switched on. The high frequencies became pronounced to the point of being unlistenable. Turn it off after each listening session and it was fine sounding as balanced as any other preamp.

 

If hifi takes time to burn in why has no one ever bothered to test the assumption by A/B ing two components known to have short warm up times but long run in times against each other, one much used, one unused?

The same reason no one can work magic in double blind cable tests, because there is no difference, and wishing it was magic ain't going to make it happen. ;-)

 

Actually, I've done that comparison several times over the years with different components and identified a difference. As mentioned, in most cases, the differences diminish with time and power cycling. For example, the difference between my CDS on day one and eight are nothing like they were the first few times when they were cycled (and new) back in '95. However, there's still a small improvement in realism around the eighth day of being switched on.

 

Incorrect. Electrolytic Capacitors go through a process called "forming". Their electrical properties change over the first few hours of use, with heat and voltage. The hotter and higher voltage, the quicker the process is.

This can impact the performance of a circuit. I came at this problem from the other direction - I was tasked to investigate an amplifier reference design that had been returned from a customer. Once I removed the broken channel the rest of it worked, except that the distortion characteristic had changed since when it had left my hands a few weeks earlier (the characteristics were saved). I discovered that the change was due to the capacitors - we knew that this customer had run the amplifier hard and hot. Replacing the capacitors in the same output stage returned it to the original performance characteristic exactly.



The blue characteristic is the original performance level with nichicon PL capacitors from a distributor, ie having been sat on a shelf for a year or two. The green characteristic is what it came back from the customer with, with formed nichicon PL capacitors. The red trace is what was observed with brand new Panasonic FCs in place of the PLs.

This exact same change in characteristic was observed across 7 separate output stages that had been subjected to the same treatment. The used capacitors were put onto a new output stage board that had not been in that customer's hands and the distortion characteristic changed - ie the effect went with the capacitors.

 

Also not true.

The bearings in motors are not at optimum when new, with use they will hit optimum. Granted after that they will start to slowly degrade.

Same goes for cars, many bearing will not be at best until some use.

 

I am A - B ing it all the time, as each new amp does the same thing and then 48 hour soak changes that, by which time the next brand new amp is listened side by side to it, so I know what happens and I mostly know why it happens. It happens so it is a reality I have to live with, you lot can please yourselves, the usual culprits will think I am mad, out my head on fairy dust, imagining it, wanting it to happen (why, my life would be a lot easier if it didn't ). I will tell you what though it seem to me IMO valve amps don't suffer as much with run in and warm-up.

It is *really* pissing me off with the speakers though, I just must find a way to run in the drivers before I sell them, the differences are gross! and it takes over a month of regular use for the bass/mid drivers to run in.

 

Richard,

I don't believe you're mad. What in your estimation is the cause for burn in? Also, do the effects diminish in strength as the component ages with your designs?

regards,

dave

 

Its the dirty window again, something in the circuit requires to warm up / settle in to start the windscreen wipers, but the bigger the window the longer it takes.

And bigger is the size and complexity of the amp, and size and complexity is 90% power supply. Just about all warm up and run in is in the power supply and the bigger and more complex then the longer it takes. The main circuit contribute some to this but relatively little. The caps needing to form are big offenders as has already been said but large toroid transformers are the other main culprit, bridge rectifiers not so much. To the point I have been contemplating trying to run big toroids in prior to amp fitting, I think Naim do something similar.

There is a known tech reason for caps, but toroids - well it must be fairys or gremlins mustn't it

 

I-S so what you are saying is that 'broken caps are broken caps'. How does that counter my claim that caps start going off from day one of being used. Sure they form with use, I stated that much.

But you have no data there to show that old caps that have been used can be made to work better than similarly formed new caps- so how does it counter my statement that things get worse with use?

In fact they aren't even the same brand of cap, so why mention it at all?

With the best will in the world Richard, you are hardly doing a blind test, so what's the point, it only reinforces your subjectivist view, it's never going to do anything to convince me.

 

Now I think it continues to happen for a long time, but a point is reached where it drops below perception. In my little amps then a couple of days, the big multi supply ones over a month and they are still perceptively getting better, then the changes drop off the radar.

Now age, well I regularly look at amps of mine up to 30 yeas old and unless faulty nothing needs doing. The whole cap changing thing is slurping, it is to make money from you - no other purpose. I have yet to find a cap that needs changing unless the amp has been stored. Electrolytics love being used and just left on, they stress when constantly switched on and off, and they dry out and go high impedance if stored and not used.

The exception to this is class A and valve amps, if the amp is hot and the cap is picking up the heat then that shortens life considerably as they dry out. The classic example was the old MF class A's they used to fry their caps regularly. And if a cap decided to explode on you it will make a bloody mess of the inside of the amp and a bloody mess of you if the amp cover is off and you are leaning over it. I have known people *permanently* damaged by that experience.

 

Why the ferk do I have to do a blind test, it is my job, and my job would be a lot easier if it didn't happen !!!!!!!!!!!

By the law of averages over the last 30 odd years one new amp would sound better than one soaked amp, it has *never* happened.

 

I think you're on to something. My NAT 101 tuner uses a SNAPS power supply and my 102 preamp uses a Hicap power supply. I've never noticed a change in sound with either after powering up from cold.

However, my CDS and 250 are different stories. The CDS (and now CDS2) uses a CDPS power supply which is effectively two supplies in one box with both a HC and SC sized transformer. The 250's power supply like the CDPS is considerably more complex (and larger) vs the SNAPS or HC. Both the CDS and 250 exhibit changes in sound consistently after power cycling. The CDS takes about eight days to even out and the 250 requires two days from a cold start.

Interesting theory about the transformers being part of the problem. So much for benign laminates ehhh?;-)