Whilst I'm unfamiliar with the OPs vintage kit I am going to go against the grain here. I disagree that newer is better. Whilst newer amps have added features such as DACs and Streaming inbuilt - good kit is still good kit, irrespective of its age.
I've heard and owned a lot of amps, including recent and decent ones. However, my rebuilt Leak valve amp from 1961, so now over 60-years old in design, is the amp I've kept and use as my main amp. This can easily hold its own against any modern amp I've heard at sensible money.
OP - if you need additional features, or want a different sound then try some other stuff out. But don't expect huge gains in sound quality if your existing kit is already of a decent quality.
Agree, and I'd argue that much newer equipment is actually inferior. There is unquestionably new technology, and much vintage equipment lacks simple -even dated- conveniences like remote control. Nevertheless, manufacturers are not what they used to be, starting with the personnel, from the engineers/craftsmen, through to the shop and showroom personnel. (Yes, there are rare, even young wizzes still around.) Few independent manufacturers remain, and the compromises made today, especially by the conglomerates, to make margins at all but the highest cost levels are indeed compromising -and hearable, and visible, etc..
I love my 21st-century Rotel A12, with its many connections, wireless features, and especially its elaborate remote control. But, it doesn't sound any better than my still-satisfying, if feature-limited 1985 original Mission Cyrus One. (Ditto for today's Cyrus One.) Rotel has designed/pursued a fairly unique history, compromised on its terms, probably at a significant cost. to protect its integrity and continue to develop its own products.
My Audi allroad turned 20 last year: even Audi doesn't make as good a
driving and feeling car at even a higher price. Today's cars have more features, but also more plastics throughout, inferior leather, inferior carpeting, etc..
It's best to hang on to what still works so nicely, unless, until you really need the features and are
prepared to compromise.