Falling out of love with tubes

Boy, the Eico was kind of a budget amp even when it was new- ceramic caps for coupling caps, cheap parts throughout... that would be a good amp to fall out of love with, and I would not abandon tubes on its account!

Tube technology has improved since the ST-70 (which was designed in the late 1950s); there are better filter caps, coupling caps, resistors, controls and there are better circuits. Even if your amp was refurbished it could easily be outclassed, even by other refurbished vintage amps like the Dynaco ST-70 or the Harmon Kardon Citation 2. But there are modern amps as you have learned that bring a lot to the table- its a big world.

Running out of the headphone jack of your computer is not the best way to get good sound out of it. IMO/IME you are better off with a DAC that runs off of the USB port and the appropriate software to make that happen (for example JRiver if you are running a music server). You very well could make good use of a good tube line stage since you are also running tape.

Thank you all for your input!  Here’s what I’ve gathered:   modern tube preamps will not sacrifice my newfound detail (including Conrad Johnson’s PV-10al), a tube preamp will give me back those rich odd-order harmonics I have a taste for, and use a DAC.

Even Paul McGowen thinks preamps are necessary:
https://www.youtube.com/watch?v=Dh27E7YKN9s

And, I if I were you, I'd consider one of the Atma preamps.
B

“...a tube preamp will give me back those rich odd-order harmonics I have a taste for...”
I think you meant even order harmonics and the CJ PV10AL delivers plenty of them, maybe a tad too much depending on your taste. Real juicy midrange if that's what are after but a bit rounded off on top.

Last night I tried a Cary CAD-5500 premamp between my Audio Refinement separates (Pre5 preamp and Multi5 amp) in an attempt to get some tube harmonics introduced in the signal chain. Didn’t last an hour as it dulled my dynamics and musicality.

Rest of system details on my system page.