Discolouration of Anodization is an Indicator of ??

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rimclean

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Hi all,

My first post here, so I'll say hello to all in the Bryston circle - Hi!

I've been looking out for a couple of second hand 2B-LPs to add to my system, and have noticed that some of them show signs of the anodization discolouring on the heat sinks whereas others do not.  I'm curious if this is a sign of anything other than the passage of time. Is it an indicator of them being driven hard over the years, and having dissipated more heat than ones that have no discolouration?  Maybe it's due to them spending their time in direct sunlight in someone's living room vs in the darkness of a studio?  Maybe a combo of the two?  Maybe some other reason? 

If anyone has any ideas I'm interested in hearing them.    Apologies if this has been discussed already - I'm too new to use the search function. 

-rm


Jozsef

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Re: Discolouration of Anodization is an Indicator of ??
« Reply #1 on: 14 Apr 2020, 07:35 am »
I have some experience with these and still have a couple of them. It's due to heat (not excess heat, BTW,) time and less than ideal anodizing. Since Bryston doesn't anodize the parts themselves, there were batches in the past that would not retain the desired look as the years went by due to some variation in the process. "Driving these hard" is not at all like doing the same with a car since there are no moving parts and the units are designed to handle whatever heat is produced at continuous full power operation.

If you put it on a radiator, hot air register, or something silly like that, the thermal cutout will simply shut the amp off before damage can occur. The purple tinged heatsinks are only a cosmetic issue and can be replaced if you so desire. (Not right now, of course.)

rimclean

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Re: Discolouration of Anodization is an Indicator of ??
« Reply #2 on: 14 Apr 2020, 10:38 pm »
Are you suggesting that there is no difference between an amplifier that has been driven close to its thermal limit for the duration of its life and one that has had light use?  My understanding is that heat is not good for electronic components.  Obviously a good design will dissipate the heat generated during normal operation, but I don't think that means one should expect the components in both amplifiers (heavy use and light use) to be in the same condition after many years of service.

So if only some of the amplifiers have the manufacturing flaw related to the anodization process, and others don't then it's really not a good indicator of anything.  I'm guessing some that have this flaw have not been run hot, and would not have changed colour, and others that don't have this flaw could have been run hot yet still look as black as the day they left the factory. 


gdayton

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Re: Discolouration of Anodization is an Indicator of ??
« Reply #3 on: 15 Apr 2020, 12:07 am »
It's not heat related at least not exclusively. Here's a great little article for reference
https://www.anoplate.com/news-and-events/why-does-anodize-fade/

Jozsef

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Re: Discolouration of Anodization is an Indicator of ??
« Reply #4 on: 15 Apr 2020, 12:17 am »
Of course there will be more aging of certain parts used at higher temperatures and longer periods but I've yet to hear of a "worn out" Bryston amplifier. My close friend, a gifted audio engineer who is not connected with the company, has told me that Bryston is truly as fanatical about selecting the best components available as they say they are. By over speccing heat sensitive parts, they are much more durable, as you would expect if they are going to treat it as their own for 20 years.

I routinely would drive to their factory (until now, obviously) with old equipment belonging to friends and customers for recapping and these would be restored to at least new performance for a very modest price because they don't see repairs as an appropriate profit source. When I've bought used 2Bs, 1Bs and .5Bs, I never even turned them on because nothing is like new after three decades but the repairs when needed were always trivial.

Lastly, in my experience, it is highly unusual for anything to be used very hard in the real world, although I'd say cars are abused routinely in various ways. Of course someone could buy a 2B LP for use where high sound levels for many hours per day are required but they probably won't.

rimclean

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Re: Discolouration of Anodization is an Indicator of ??
« Reply #5 on: 17 Apr 2020, 12:49 am »
What I'm getting from all this is that I should stop worrying and buy some amplifiers.  I'm okay with that.

FullRangeMan

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Re: Discolouration of Anodization is an Indicator of ??
« Reply #6 on: 17 Apr 2020, 12:54 am »
What can inform you the amp age is the serial number.