How good is your hearing ? And how do you know ?

Test was maybe 4 months ago, 13k is it for me now which frankly I am surprised I still am at that level.
With all the live bands up against the massive stacks of the 70,s and 80,s. Playing bass in my band.
And working in heavy machinery manufacturing for last 40 years!

Fortunately no tinnitus yet!

Yes I wear custom ear plugs at work and have done for decades but not at concerts or when I was playing bass and I was always astonished at what spl I could achieve with a Peavey 100watt tube head and 2x15 cab!

Now how does any of that affect my listening enjoyment or ability to detect changes with different components, cables, tweaks etc?

Not at all I believe.

I am happy, I can hear changes, I enjoy my music, like right now.
That is all that matters to me.

Don't worry too much, as mentioned, I can currently only hear up to about 12k, and even to hear that I will have to really concentrate. But I could clearly differentiate between my Gryphon Mephisto power amp and my CH Precision M1 amp. Both being good power amps, but with different sound. So most likely it doesn't have too much to do with frequency, it's just a different sound, and some people will choose amp A, others amp B. 

Finally. Someone has a great transistor amp - Gryphon. How is FM Acoustics compared to Gryphon if you are familiar ?

@inna 
Unfortunately I have no experience with the FM Acoustics. Gryphon is great indeed, nevertheless, I'm now using the CH Precision M1. As stated before, both are very good amps, but my personal preference made me change from Gryphon to CHP. Still using Gryphon amps for the bass towers. 

han_n,
I see. Probably your choice of speakers also influences which one of the two you prefer. Swiss know transistors well, no doubt.