Solid states more accurate than tubes?

jaferd -- Accuracy in a system can be a double-edged sword.   If fate decrees it that your favorite music has been recorded terribly, sometimes it helps if your system is slightly more forgiving, i.e., more euphonic & less accurate.

isn’t there only one true fidelity

No. We all hear differently. We all remember differently.
Different aspects of reproduced sound are preferred.

I have some tube amps.  I've been recently swapping out interconnects.  The difference is apparent.  Of course, how apparent depends on the amp and the speakers.  

I took these over to a buddy's place who had also heard the differences at my place.  We played on his nice SS system.  We pretty much could not tell the difference.  

Why?  Only guesses, but we all (others too) heard distinct differences on some of my tube amps.  

I assume by true fidelity you mean high fidelity? High fidelity in audio means reproduction of sound without distortion and color that remains true to the original. In order to achieve that you need very accurate measuring equipment. The biggest obstacle now is speakers and room. 

SS is always more accurate.