Hi.
So to sum up we don't have instruments available to day which can measure the difference we can hear with our ear yet we cannot make measurements to explain the difference in what we hear with our ear. There is lacking in a tool and a measurement, please find this tool and measurement to explain what we hear with our ear.
John
As an audiophile/DIYer & an EE, I fully agree that the the objective measurement done with the instrumentatioin available todate can't tell what we HEAR.
So until that day in the remote future when such instrumantion is available to provide data relevant to what we hear, let us
let our ear to have the final say.
Back to the issue of replacing the stock PE caps with PP caps to get better sound that most most audio fans fond of doing. I've got the opposite sonic conclusion with the O/P coupling caps for my one-stage RIAA tube phonostage.
The WIMA metallized film caps I installed to replace the exsiting no-name PE film caps sounded much much worse that the PE film caps! Givng them the benifits of the doubt - the WIMA new PP caps need breaking-in to give good sound, I carried out a crash breaking-in process with a 20Hz-20KHz sweeping signals into the new WIMA PP caps already installed in my amp for 8 hours non-stop
at pretty high voltage (higher than its normal audio voltage range) to achieve the intended quick breaking-in result.
Such crash breaking-in process did improve a bit the sound of the new WIMA PP caps, but they still sound relatively dull, veiled, & lack of transparancy & details than the old PE film caps. The sonic difference was so huge that I can conclude such PE to PP caps swap is a complete failure (w/o need of any DBTs at all).
I had no choice but to swap back to the old no-name PE caps & threw out the new WIMA PP caps. The sound comes right back to fast, clean, transparent & musically like before.
Well, listening is believing.
c-J