Break in time that extends to months or maybe even years!!

I concur with @almarg, @hilde45, and @zavato… Control of independent variables is of the utmost importance in the review process, and should be implemented as much as possible to achieve reasonably meaningful findings.

In a perfect world, twin copies of the target component or cable should be used for periodic comparisons of performance throughout the break-in process… One copy being the full break-in target, and the second one as a control with “low mileage”. Now suddenly, I hit myself, because I just realized that I had a perfect opportunity to do that when I examined the Rowland M535 bridged a spell ago… I should have started in stereo mode, and used one of the two units as a low mileage control, instead of breaking-in the pair as a bridged set. Oh well, next time I evaluate a bridgeable amp, I’ll apply this technique for sure.

Would be nice to track voltages, air temperature, and humidity… Next time I am born I’ll make sure I stay fully sighted, so I can read measuring equipment… Oh well *Grins!*

On the other hand, I do control the test environment as much as possible, as follows:

• I maintain system configuration to be invariant during each individual evaluation phase. This means that all components remain the same; cabling remains the same; usage of AC outlets remains the same; no equipment has moved around stands; layout of cabling on the floor remains the same; no furniture has been moved, orientation of window treatments remains the same.

• All ancillary equipment is already well stabilized: In my case, all equipment has been with me between two years (cabling) and 14 years (CD transport)… I was forgetting equipment support benches (60 years).

• Break-in process continues 24/7, except for power-off time during thunderstorms and for discharging capacitors (did this twice). Did any critical listening at least several hours after the last power-up… More typically, days or weeks after.

• I make consistent use of review material… A test CD contains the same sampling of music tracks that I have used for evaluating equipment at home, at shows, and at stores for the last 15 years… In addition, I use several other CDs representative of music genres of interest to me.

• While I listen to entire CDs during critical listening, I do concentrate on particular passages that I have known to expose possible flaws or merits in a review target: harshness from intermodulative artifacts, pillowing/unspecific bass, harmonic exposure changes in broad treble to bass arpeggios, transient clarity vs opaqueness, decay complexity, staging/imaging changes, very low level information, ambient noises, performers’ subvocalizations.

• I document observations in contemporaneous notes also logging dates and break-in hours, which when cleaned up form the basis for diary posts, and in an ancient past, I have integrated into published reviews.

• Use a break-in tracker spreadsheet… This maintains break-in status for each day, hours of operation each day, start time, power down time, total hours count since beginning of project, and completion date projections.

•       At the end of each project phase, for instance use of an integrated as a complete integrated, I make minimal changes to start the next phase, which might be for example feeding the linelevel signal from the linestage of the integrated into my reference monoblocks… I will use for this the same pair of well broken in XLR ICs that I have been using for the last two years from my reference DAC to the monos.

•   I will run this configuration for at least a couple days before any new critical listening, and will use the same tracks and passages that I used on the integrated. I will probably need to go back and forth between full integrated and its linestage subsystem into the monos to derive a reasonable assessment of the difference. Yes I know, the reintroduction of an IC will somewhat smear the results.

• * I would then use the same XLR ICS when I test the output of my reference DAC into the integrated linestage + amplification subsystem.  

As you might imagine, I can’t examine dozens or even a handful of components a year this way: It is a very time-consuming process. Never the less, it is for me a happy labor of love which I enjoy sharing with fellow lovers of music and sound… Others may feel otherwise.

Regards, G.