Burn in question

There is a portion that thinks that burn in is snake oil theory and others that think that is an absolute must ...

Here is question given to me about this issue

A Luxman analog tuner the T2 includes
About 35 electrolytic capacitors
About 25 transistors some of them fets
About 6-7 IC
About 15 adjustment points

Question is that if burn in is a must then how it was possible to align the tuner at factory with parts that are not burned in ?

Remember that in an analog tuners extreme precision is required to achieve performance...which means that an analog tuner has far more accurate adjustments to be done than a few ma bias or offset more or less ....

What do you think ?
 

Ian Finch

Member
Paid Member
2010-04-11 4:22 am
Coffs Harbour, NSW
Then again, if you are not getting fresh stock electrolytics from your supplier, using old ones, or using amps held in storage a while, the caps probably need re-forming (rather than burning-in) before being powered up. In some applications, they don't get enough time or potential to form the insulation layer properly.

Ask anyone who has used a lot of Rubycon Blackgates caps and is honest enough to admit that some NOS and even new product fitted in some locations, went bad in a matter of days and the SQ was "off".
 
I believe that those who hear and report on the good effects of "burn in" are actually using polarised capacitors that have not been reformed and have a very high leakage.
Their "burn in" is a very slow reforming of the capacitors while in circuit, and what they are hearing is a slow reduction in the leakage currents where correct operation is for zero leakage current.

The easy solution is to reform all your polarised electrolytics just before assembling the equipment.
 
tommy1000 burn in is not a test is a procedure ...as about the test the procedure and the quality of the products of that era the quality of built , testing procedure , and long term stability was the highest available standard from companies like Luxman and Sansui even for cheap products ...

Andrew if i may ? that means that in a tuner production where tolerance or "condition " of the part is critical for a precise alignment that will mean that by some means Luxman was getting "ready to use" parts that have already been through some "procedure" that makes them ready to operate with out burn in ?

well even though reasonable doesn't sound right ...
 
Do the Tuner manufacturers choose an unsuitable capacitor type that would affect the performance of the "production line tuning set-up"?

What would be the point of building a test cell and manning it with expensive labour if they KNEW that an unreformed polarised electrolytic would undo their good work?

To avoid manual or computer-aided set-up the manufacturers have jumped onto the digital bandwagon. They in general do not need any analogue stages to be "tuned in" the design just uses "bits" to give the desired goal/signal.

That saves the manufacturer money once the design is finalised. Produce millions of digital quality product and they all perform the same.
 
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Andrew please don't make this difficult to talk about

Burn in aspect is the same now and then
At the time and when tuners was analog the reasonable conclusion is that you cannot make proper and precise alignment unless your parts have already been burned in ( that is by the aspect that burn in is a must )

The other aspect is that burn in is snake oil theory

My example for analog tuners is given on the aspect that an analog tuner will need far more precision than an amplifier that will survive fine with a bit of bias or offset more due to component tolerance which might occur from parts that haven't burn in .
 
On production facility it is probably possible to predict what will happen in one amplifier before and after burn in For example if bias stabilizes on production to 40ma and after the amplifier is burned in the bias is at 45 ma then the factory might tune accordingly with the prediction that bias will eventually stabilize to a desirable level .

In a analog tuner you cannot do that The tuner has to perform with precision and stay like that from the moment that leaves the factory and for the rest of its life

Imagine a tuner that cannot indicate FM stereo but it will after it operates 15 days

Logic like that makes no sense ...
 
If "burn in" is the incorrect word used instead of excessive leakage current, then leakage current is only significant with electroltyic capacitors. I believe some paper in oils also leak.

If the manufactuers choose the correct type of capacitors, then the set up of the tuner will not be affected by whether the tuner includes some electrolytics in locations that don't affect the "tuning set up".

If low leakage typical of plastic film capacitors are used in critical locations then leakage will not be a problem.
 
On production facility it is probably possible to predict what will happen in one amplifier before and after burn in For example if bias stabilizes on production to 40ma and after the amplifier is burned in the bias is at 45 ma then the factory might tune accordingly with the prediction that bias will eventually stabilize to a desirable level .

In a analog tuner you cannot do that The tuner has to perform with precision and stay like that from the moment that leaves the factory and for the rest of its life

Imagine a tuner that cannot indicate FM stereo but it will after it operates 15 days

Logic like that makes no sense ...
A bigger problem could be drift in the tuned frequency due to temperature changes. That affects the capacitors and that is where you may see the use of NP0 and N150 chosen to compensate for temperature change.
 
RF electronics does not suffer from 'burn-in'. It may suffer from long-term drift, over a period of decades. If a component genuinely needs any 'burn-in' then that is the task of the component manufacturer, not the user. If I buy a 47pF capacitor for a tuned circuit then I can reasonably expect that it will be 47pF (within the stated tolerance range) and will stay at 47pF for a few decades at least. Experience shows that RF capacitors made 60-70 years ago are likely to still be fine today.

Long-term problems come from electrolytics and paper dielectrics.

Audio 'burn-in' is a persistent myth. In most cases the only thing which changes is the tastes of the listener, as he becomes used to a new sound due to a changed component having a slightly different value from the previous one.
 

Welcome

Member
2013-03-11 10:52 am
I work in electronics production, with things far more accurate than audio/consumer stuff, and we never burn in anything. This includes electrolytic capacitors, standard Nichicon fare, and they work and measure identically, either straight from the factory, or after years of non-use, or years of heavy use.
 
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