Tweaks to Add A Little Treble Emphasis...

How old is your aesthetix calypso? Maybe it is time to retube. You can't use interconnects or power cords as tone control if the root cause is aged tubes.

What kind of speakers are you using? Also, how is the room furnished and how much soft surface is there? Too much thick carpet, stuffed furniture, and especially heavy drapes and wall hangings can overdamp a room, killing the treble unless you are directly in the sweet spot.

Also, 12AX7s would definitely brighten up the sound compared to 5751s. Also, better power cords won't specifically add treble, but the right ones make everything more clear and dynamic, but the clarity applies to all frequencies.

Do you want to play with your crossover at all? If yes, you can reduce the series tweeter resistor value by .5 or 1.0 ohm. That will result in increasing the output of the tweeter by a bit.

Enjoy,
Bob

I agree with those who have suggested starting with speaker placement and room acoustics. It would be useful to know more about your speakers and room.

wow, what a fantastic collection of suggestions - thanks sincerely, all. to the questions asked of me:

Sidssp: the calypso is only a few years old, however, more importantly, the tubes were just purchased last week - tested new at the time of purchase.

Johnnyb53: speakers are gallo stradas (more on that below).

Bob: reducing the tweeter resistance sounds interesting, but i have no idea how to go about doing something like that.

to make a long story longer, once my son got mobile, i made significant changes to my 2-channel system to make things a bit safer for him. the biggest being replacing my Wilson Audio Cubs with Anthony Gallo Stradas. I find the Stradas to be immensely satisfying, and often marvel at how large they sound given their diminutive size.

if there's one thing i'd like to tweak is a little more 'sizzle' in the treble.

many thanks for all the suggestions so far - you guys have given me a lot of great options to explore!